Cover Page for Proposal NASA Proposal Number Submitted …owocki/xfr/Owocki-ATP-May10-N... ·...

Cover Page for ProposalSubmitted to the

National Aeronautics andSpace Administration

NASA Proposal Number

TBD on Submit

NASA PROCEDURE FOR HANDLING PROPOSALS

This proposal shall be used and disclosed for evaluation purposes only, and a copy of this Government notice shall be applied to any reproduction orabstract thereof. Any authorized restrictive notices that the submitter places on this proposal shall also be strictly complied with. Disclosure of thisproposal for any reason outside the Government evaluation purposes shall be made only to the extent authorized by the Government.

SECTION I - Proposal Information

Principal Investigator

Stanley OwockiE-mail Address

[email protected] Number

302-831-8357Street Address (1)

104 The GrnStreet Address (2)

217 Sharp LabCity

NewarkState / Province

DEPostal Code

19716-2593Country Code

USProposal Title : Dynamical Models for High-Energy Emission from Massive Stars

Proposed Start Date Proposed End Date Total Budget

540,713.00Year 1 Budget




0.00SECTION II - Application Information

NASA Program Announcement Number

NNH10ZDA001N-ATPNASA Program Announcement Title

Astrophysics TheoryFor Consideration By NASA Organization (the soliciting organization, or the organization to which an unsolicited proposal is submitted)

NASA , Headquarters , Science Mission Directorate , AstrophysicsDate Submitted Submission Method

Electronic Submission OnlyGrants.gov Application Identifier Applicant Proposal Identifier

Type of Application

NewPredecessor Award Number Other Federal Agencies to Which Proposal Has Been Submitted

International Participation

YesType of International Participation

OtherSECTION III - Submitting Organization Information

DUNS Number

059007500CAGE Code

015X1Employer Identification Number (EIN or TIN)

516000297Organization Type

8HOrganization Name (Standard/Legal Name)

University Of DelawareCompany Division

Organization DBA Name Division Number

Street Address (1)

220 HULLIHEN HALLStreet Address (2)

City

NEWARKState / Province

DEPostal Code

197160099Country Code

USASECTION IV - Proposal Point of Contact Information

Name

Stanley OwockiEmail Address

[email protected] Number

302-831-8357SECTION V - Certification and Authorization

Certification of Compliance with Applicable Executive Orders and U.S. CodeBy submitting the proposal identified in the Cover Sheet/Proposal Summary in response to this Research Announcement, the Authorizing Official of the proposing organization (or the individualproposer if there is no proposing organization) as identified below:

• certifies that the statements made in this proposal are true and complete to the best of his/her knowledge;

• agrees to accept the obligations to comply with NASA award terms and conditions if an award is made as a result of this proposal; and

• confirms compliance with all provisions, rules, and stipulations set forth in the two Certifications and one Assurance contained in this NRA (namely, (i) the Assurance of Compliance withthe NASA Regulations Pursuant to Nondiscrimination in Federally Assisted Programs, and (ii) Certifications, Disclosures, and Assurances Regarding Lobbying and Debarment andSuspension.

Willful provision of false information in this proposal and/or its supporting documents, or in reports required under an ensuing award, is a criminal offense (U.S. Code, Title 18, Section 1001).

Authorized Organizational Representative (AOR) Name AOR E-mail Address Phone Number

AOR Signature (Must have AOR's original signature. Do not sign "for" AOR.) Date

FORM NRESS-300 Version 3.0 Apr 09

PI Name : Stanley Owocki

Organization Name : University Of Delaware


TBD on SubmitProposal Title : Dynamical Models for High-Energy Emission from Massive Stars

SECTION VI - Team Members

Team Member Role

PITeam Member Name

Stanley OwockiContact Phone

302-831-8357E-mail Address

[email protected]

Organization/Business Relationship

University Of DelawareCage Code

015X1DUNS#

059007500


NoU.S. Government Agency Total Funds Requested

0.00

Team Member Role

Co-ITeam Member Name

Jamie HolderContact Phone


[email protected]


University Of DelawareCage Code

015X1DUNS#

059007500



0.00

Team Member Role

Co-I/Institutional PITeam Member Name

David CohenContact Phone


[email protected]


Swarthmore CollegeCage Code

00ST5DUNS#

073755381



0.00

Team Member Role

CollaboratorTeam Member Name

Michael CorcoranContact Phone


[email protected]


Universities Space Research AssociationCage Code

1F731DUNS#

056912900



0.00

Team Member Role


Atsuo OkazakiContact Phone

11-841-1161 x 2264E-mail Address

[email protected]


NASA Goddard Swift Science CenterCage Code

ZZZ49DUNS#

999999949


YesU.S. Government Agency Total Funds Requested

0.00

Team Member Role


Gustavo RomeroContact Phone

54-221-4254909 x115

E-mail Address

[email protected]


CONSEJO NACIONAL DE INVESTIGACIONES CIENTIFICAS YTECNICAS

Cage Code

SBU13DUNS#

971330527


YesU.S. Government Agency Total Funds Requested

0.00






SECTION VII - Project Summary

Massive stars are prominent sources of X-rays and gamma-rays detected by both targeted and survey observations from orbitingtelescopes like Chandra, XMM/Newton, RXTE, and Fermi. Such high-energy emissions represent key probes of the dynamics ofmassive-star mass loss, and their penetration through many magnitudes of visible interstellar extinction makes them effective beaconsof massive stars in distant reaches of the Galaxy, and in young, active star-forming regions. The project proposed here will develop acomprehensive theoretical framework for interpreting both surveys and targeted observations of high-energy emission from massivestars. It will build on our team's extensive experience in both theoretical models and observational analyses for three key types ofemission mechanisms in the stellar wind outflows of these stars, namely: 1) Embedded Wind Shocks (EWS) arising from internalinstabilities in the wind driving; 2) shocks in Colliding Wind Binary (CWB) systems; and 3) High-Mass X-ray Binaries (HMXB)systems with interaction between massive-star wind with a compact companion (neutron star or black hole). Taking advantage ofcommonalities in the treatment of radiative driving, hydrodynamics, shock heating and cooling, and radiation transport, we willdevelop radiation hydrodynamical models for the key observational signatures like energy distribution, emission line spectrum, andvariability, with an emphasis on how these can be used in affiliated analyses of both surveys like the recent Chandra mapping of theCarina association, and targeted observations of galactic X-ray and gamma-ray sources associated with each of the above specificmodel types. The promises of new clumping-insensitive diagnostics of mass loss rates, and the connection to mass transfer andbinarity, all have broad relevance for understanding the origin, evolution, and fate of massive stars, in concert with elements of NASA'sStrategic Subgoal 3D. Building on our team's expertise, the project emphasizes training of a new generation of students andpost-doctoral researchers to model and analyze observations by current and future NASA X-ray and gamma-ray observatories.






SECTION VIII - Other Project Information

Proprietary Information

Is proprietary/privileged information included in this application?

Yes

International Collaboration

Does this project involve activities outside the U.S. or partnership with International Collaborators?

Yes

Principal Investigator

NoCo-Investigator

NoCollaborator

YesEquipment

NoFacilities

No

Explanation :

Atsuo Okazaki from Japan and Gustavo Romero of Argentina will participate as collaborators. Neither will receive any funding from theproject.

NASA Civil Servant Project Personnel

Are NASA civil servant personnel participating as team members on this project (include funded and unfunded)?

No

Fiscal Year Fiscal Year Fiscal Year Fiscal Year Fiscal Year

Number of FTEs Number of FTEs Number of FTEs Number of FTEs Number of FTEs







Environmental Impact

Does this project have an actual or potential impact on the environment?

NoHas an exemption been authorized or an environmental assessment (EA) or anenvironmental impact statement (EIS) been performed?

No

Environmental Impact Explanation:

Exemption/EA/EIS Explanation:







Historical Site/Object Impact

Does this project have the potential to affect historic, archeological, or traditional cultural sites (such as Native American burial or ceremonial grounds) or historic objects(such as an historic aircraft or spacecraft)?

No

Explanation:






SECTION IX - Program Specific Data

Question 1 : Short Title:

Answer: Dynamical Models for High-Energy Emission from Massive Stars

Question 2 : Type of institution:

Answer: Educational Organization

Question 3 : Will any funding be provided to a federal government organization including NASA Centers, JPL, other Federal agencies,government laboratories, or Federally Funded Research and Development Centers (FFRDCs)?

Answer: No

Question 4 : Is this Federal government organization a different organization from the proposing (PI) organization?

Answer: N/A

Question 5 : Does this proposal include the use of NASA-provided high end computing?

Answer: No

Question 6 : Research Category:

Answer: 1) Theory/computer modeling

Question 7 : Team Members Missing From Cover Page:

Answer:

none

Question 8 : This proposal contains information and/or data that are subject to U.S. export control laws and regulations including ExportAdministration Regulations (EAR) and International Traffic in Arms Regulations (ITAR).

Answer: No

Question 9 : I have identified the export-controlled material in this proposal.

Answer: N/A

Question 10 : I acknowledge that the inclusion of such material in this proposal may complicate the government's ability to evaluate theproposal.

Answer: N/A

Question 11 : Topic Category:

Answers :

Stellar Astrophysics


Collapsed Objects and X-ray Astrophysics






SECTION X - Budget

Cumulative Budget

Budget Cost Category

Funds Requested ($)

Year 1 ($) Year 2 ($) Year 3 ($) Year 4 ($) Total Project ($)

A. Direct Labor - Key Personnel 19,603.00 20,338.00 21,102.00 0.00 61,043.00

B. Direct Labor - Other Personnel 80,340.00 83,354.00 86,477.00 0.00 250,171.00

Total Number Other Personnel 3 3 3 0 9

Total Direct Labor Costs (A+B) 99,943.00 103,692.00 107,579.00 0.00 311,214.00

C. Direct Costs - Equipment 5,000.00 0.00 0.00 0.00 5,000.00

D. Direct Costs - Travel 8,500.00 8,820.00 9,149.00 0.00 26,469.00

Domestic Travel 5,500.00 5,707.00 5,920.00 0.00 17,127.00

Foreign Travel 3,000.00 3,113.00 3,229.00 0.00 9,342.00

E. Direct Costs - Participant/Trainee Support Costs 0.00 0.00 0.00 0.00 0.00

Tuition/Fees/Health Insurance 0.00 0.00 0.00 0.00 0.00

Stipends 0.00 0.00 0.00 0.00 0.00

Travel 0.00 0.00 0.00 0.00 0.00

Subsistence 0.00 0.00 0.00 0.00 0.00

Other 0.00 0.00 0.00 0.00 0.00

Number of Participants/Trainees 0

F. Other Direct Costs 4,000.00 4,150.00 4,306.00 0.00 12,456.00

Materials and Supplies 2,000.00 2,075.00 2,153.00 0.00 6,228.00

Publication Costs 2,000.00 2,075.00 2,153.00 0.00 6,228.00

Consultant Services 0.00 0.00 0.00 0.00 0.00

ADP/Computer Services 0.00 0.00 0.00 0.00 0.00

Subawards/Consortium/Contractual Costs 0.00 0.00 0.00 0.00 0.00

Equipment or Facility Rental/User Fees 0.00 0.00 0.00 0.00 0.00

Alterations and Renovations 0.00 0.00 0.00 0.00 0.00

Other 0.00 0.00 0.00 0.00 0.00

G. Total Direct Costs (A+B+C+D+E+F) 117,443.00 116,662.00 121,034.00 0.00 355,139.00

H. Indirect Costs 59,595.00 61,831.00 64,148.00 0.00 185,574.00

I. Total Direct and Indirect Costs (G+H) 177,038.00 178,493.00 185,182.00 0.00 540,713.00

J. Fee 0.00 0.00 0.00 0.00 0.00

K. Total Cost (I+J) 177,038.00 178,493.00 185,182.00 0.00 540,713.00

Total Cumulative Budget 540,713.00






SECTION X - Budget

Start Date :01 / 01 / 2011

End Date :12 / 31 / 2011

Budget Type :Project

Budget Period :1

A. Direct Labor - Key Personnel

Name Project RoleBase

Salary ($)

Cal. Months Acad.

Months

Summ.

Months

Requested

Salary ($)

Fringe

Benefits ($)

Funds

Requested

($)

Owocki , Stanley PI 0.00 1 14,817.00 4,786.00 19,603.00

Total Key Personnel Costs 19,603.00

B. Direct Labor - Other Personnel

Number of

PersonnelProject Role Cal. Months Acad. Months Summ. Months

Requested

Salary ($)

Fringe Benefits

($)

Funds

Requested ($)

1 Post Doctoral Associates 12 40,000.00 12,920.00 52,920.001 Graduate Students 12 23,000.00 920.00 23,920.001 Undergraduate Students 3 3,500.00 0.00 3,500.00

3 Total Number Other Personnel Total Other Personnel Costs 80,340.00

Total Direct Labor Costs (Salary, Wages, Fringe Benefits) (A+B) 99,943.00






SECTION X - Budget

Start Date :01 / 01 / 2011

End Date :12 / 31 / 2011


Budget Period :1

C. Direct Costs - Equipment

Item No. Equipment Item Description Funds Requested ($)

1 computer workstation 5,000.00

Total Equipment Costs 5,000.00

D. Direct Costs - Travel

Funds Requested ($)

1. Domestic Travel (Including Canada, Mexico, and U.S. Possessions) 5,500.00

2. Foreign Travel 3,000.00

Total Travel Costs 8,500.00

E. Direct Costs - Participant/Trainee Support Costs

Funds Requested ($)

1. Tuition/Fees/Health Insurance 0.00

2. Stipends 0.00

3. Travel 0.00

4. Subsistence 0.00

Number of Participants/Trainees: Total Participant/Trainee Support Costs 0.00






SECTION X - Budget

Start Date :01 / 01 / 2011

End Date :12 / 31 / 2011


Budget Period :1

F. Other Direct Costs

Funds Requested ($)

1. Materials and Supplies 2,000.00

2. Publication Costs 2,000.00

3. Consultant Services 0.00

4. ADP/Computer Services 0.00

5. Subawards/Consortium/Contractual Costs 0.00

6. Equipment or Facility Rental/User Fees 0.00

7. Alterations and Renovations 0.00

Total Other Direct Costs 4,000.00

G. Total Direct Costs

Funds Requested ($)

Total Direct Costs (A+B+C+D+E+F) 117,443.00

H. Indirect Costs

Indirect Cost Rate (%) Indirect Cost Base ($) Funds Requested ($)

MTDC 53.00 117,443.00 59,595.00

Cognizant Federal Agency: Office of Naval Research, Linda B. Shipp,

703-696-8559Total Indirect Costs

59,595.00

I. Direct and Indirect Costs

Funds Requested ($)

Total Direct and Indirect Costs (G+H) 177,038.00

J. Fee

Funds Requested ($)

Fee 0.00

K. Total Cost

Funds Requested ($)

Total Cost with Fee (I+J) 177,038.00






SECTION X - Budget

Start Date :01 / 01 / 2012

End Date :12 / 31 / 2012


Budget Period :2



Salary ($)

Cal. Months Acad.

Months

Summ.

Months

Requested

Salary ($)

Fringe

Benefits ($)

Funds

Requested

($)




Number of


Requested

Salary ($)

Fringe Benefits

($)

Funds

Requested ($)









SECTION X - Budget

Start Date :01 / 01 / 2012

End Date :12 / 31 / 2012


Budget Period :2



Total Equipment Costs 0.00


Funds Requested ($)





Funds Requested ($)


2. Stipends 0.00

3. Travel 0.00

4. Subsistence 0.00







SECTION X - Budget

Start Date :01 / 01 / 2012

End Date :12 / 31 / 2012


Budget Period :2


Funds Requested ($)










Funds Requested ($)


H. Indirect Costs


MTDC 53.00 116,662.00 61,831.00



61,831.00


Funds Requested ($)


J. Fee

Funds Requested ($)

Fee 0.00

K. Total Cost

Funds Requested ($)







SECTION X - Budget

Start Date :01 / 01 / 2013

End Date :12 / 31 / 2013


Budget Period :3



Salary ($)

Cal. Months Acad.

Months

Summ.

Months

Requested

Salary ($)

Fringe

Benefits ($)

Funds

Requested

($)




Number of


Requested

Salary ($)

Fringe Benefits

($)

Funds

Requested ($)









SECTION X - Budget

Start Date :01 / 01 / 2013

End Date :12 / 31 / 2013


Budget Period :3





Funds Requested ($)





Funds Requested ($)


2. Stipends 0.00

3. Travel 0.00

4. Subsistence 0.00







SECTION X - Budget

Start Date :01 / 01 / 2013

End Date :12 / 31 / 2013


Budget Period :3


Funds Requested ($)










Funds Requested ($)


H. Indirect Costs


MTDC 53.00 121,034.00 64,148.00



64,148.00


Funds Requested ($)


J. Fee

Funds Requested ($)

Fee 0.00

K. Total Cost

Funds Requested ($)







SECTION X - Budget

Start Date : End Date : Budget Type :Project

Budget Period :4



Salary ($)

Cal. Months Acad.

Months

Summ.

Months

Requested

Salary ($)

Fringe

Benefits ($)

Funds

Requested

($)

Owocki , Stanley PI 0.00 0.00 0.00 0.00

Total Key Personnel Costs 0.00


Number of


Requested

Salary ($)

Fringe Benefits

($)

Funds

Requested ($)

0 Total Number Other Personnel Total Other Personnel Costs 0.00

Total Direct Labor Costs (Salary, Wages, Fringe Benefits) (A+B) 0.00






SECTION X - Budget


Budget Period :4





Funds Requested ($)

1. Domestic Travel (Including Canada, Mexico, and U.S. Possessions) 0.00

2. Foreign Travel 0.00

Total Travel Costs 0.00


Funds Requested ($)


2. Stipends 0.00

3. Travel 0.00

4. Subsistence 0.00







SECTION X - Budget


Budget Period :4


Funds Requested ($)

1. Materials and Supplies 0.00

2. Publication Costs 0.00






Total Other Direct Costs 0.00


Funds Requested ($)

Total Direct Costs (A+B+C+D+E+F) 0.00

H. Indirect Costs


0.00 0.00 0.00

0.00 0.00 0.00

0.00 0.00 0.00

0.00 0.00 0.00

0.00 0.00 0.00

0.00 0.00 0.00

0.00 0.00 0.00

0.00 0.00 0.00

0.00 0.00 0.00

0.00 0.00 0.00

Cognizant Federal Agency: Total Indirect Costs 0.00


Funds Requested ($)

Total Direct and Indirect Costs (G+H) 0.00

J. Fee

Funds Requested ($)

Fee 0.00

K. Total Cost

Funds Requested ($)

Total Cost with Fee (I+J) 0.00


Contents

1 Introduction 1

2 Background on Relevant Work by Investigators 1

2.1 Embedded Wind Shocks (EWS) in single OB stars . . . . . . . . . . . . . . . . . . . 12.2 Colliding Wind Binary (CWB) systems . . . . . . . . . . . . . . . . . . . . . . . . . 32.3 X-rays and γ-rays from High-Mass X-ray Binaries (HMXB) . . . . . . . . . . . . . . 5

3 Proposed Research 7

3.1 Radiation-Hydrodynamical Simulation of X-ray Emission and Absorption . . . . . . 73.2 Effect of Clumping & Radiative Forces on CWB Shocks . . . . . . . . . . . . . . . . 83.3 Dynamical Models of X-rays and γ-rays from HMXB . . . . . . . . . . . . . . . . . . 93.4 Simulation Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

4 Personnel & Work Plan 10

4.1 Qualifications and Expected Contributions of Investigators . . . . . . . . . . . . . . 104.2 Work Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

5 Broad Relevance of Proposed Project 12

5.1 Massive Stars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125.2 Impact on current and future NASA missions . . . . . . . . . . . . . . . . . . . . . . 125.3 Education and Training Impact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

1 Introduction

Massive stars are the powerhouses of the Milky Way. Even before exploding as violent supernovaethat seed the galaxy with heavy elements and help trigger new generations of star formation, theirhigh luminosity lights up and ionizes the nearby interstellar medium, and drives strong, high-speedstellar wind mass outflows. Massive stars are also prominent stellar sources of X-rays, as detected inboth targeted and survey observations by orbiting X-ray telescopes (e.g. Chandra, XMM/Newton,RXTE); and they are linked to a growing subset of galactic gamma-ray sources detected by bothground-based Cerenkov telescopes (e.g. HESS, Veritas, Magic) and orbiting gamma-ray missions(e.g. Swift, AGILE, Fermi). Collectively such massive-star systems provide important laboratoriesfor the fundamental process generating high-energy radiation. The overarching goal of the projectproposed here is to develop a sound theoretical framework for interpreting observations of suchhigh-energy emission from massive stars.

The PI and research team have broad and extensive experience in both theoretical modelingand observational analyses of three principal types of massive star high-energy emission, namely:1) Embedded Wind Shocks (EWS) arising from intrinsic instabilities in the radiatively driven wind(see §2.1); 2) Colliding Wind Binary (CWB) shocks in systems of two massive stars (e.g. O+O orO+WR; §2.2). 3) High-Mass X-Ray Binary (HMXB) systems of OB star + compact companion(cc, i.e. either a neutron star or black hole; §2.3). While there are important distinctions for eachtype, they all share a commonality that the X-ray and γ-ray emission is linked to the massive star’sradiatively driven wind. The project proposed here would exploit and build on our group’s broadexpertise and infrastructure of theoretical codes for radiation hydrodynamics of massive-star winds,and analysis tools for massive-star X-rays and γ-rays. Taking full advantage of the commonalitiesin treatment of radiative driving, hydrodynamics, shock acceleration and heating, and radiationtransport, it will develop radiation hydrodynamical models for the key observational signatureslike energy distribution, emission spectrum and variability, and apply these to interpreting bothsurveys (e.g. the recent Chandra mapping of Carina) and targeted observations of galactic X-rayand γ-ray sources associated with each of the above specific model types.

As detailed in §3, key issues for each type are: 1) Effect of clumping and porosity on the X-rayand γ-ray emission and absorption central to inference of wind mass loss rates; 2) Role of radiativeforces in altering the wind-wind collision and resulting X-ray emission. 3) Role of absorption ofX-rays and γ-rays in determining the observed light curve and spectral variations with orbitalphase. The promises of new clumping-insensitive diagnostics of mass loss rates, and the connectionto accretion mass transfer and binarity, all have broad relevance for understanding the origin,evolution, and fate of massive stars (§5.1).

As a background to the specific research proposals described in §3, the following section (§2)further describes the three targeted emission source types, with particular emphasis on our team’sexperience in modeling these. Later sections describe our personnel and work plan (§4), and thebroader relevance of the project to NASA’s goals, for science impact (§5.1-5.2), for current andfuture NASA missions (§5.2), and for education and training (§5.4).

2 Background on Relevant Work by Investigators

2.1 Embedded Wind Shocks (EWS) in single OB stars

The driving of massive-star winds by line-scattering of the star’s continuum radiation is subject tothe strong, intrinsic “Line-Deshadowing Instability” (Lucy 1970; Owocki & Rybicki 1984, 1985).This intrinsic instability is likely a root cause of the inferred extensive clumping and X-ray emissionof such winds. Dating back more than two decades, PI Owocki and his collaborators have led efforts

1

ρ/ρ 0

r(R*)

Height (R*)

log(

ρ)(g/cm3)

time(hr)

time(hr)

v(km/s)

v(km/s)

log(

ρ)(g/cm3)

Figure 1: Left: Results of 1D Smooth-Source-Function (SSF) simulation of the line-deshadowinginstability. The line plots show the spatial variation of velocity (upper) and density (lower) at afixed, arbitrary time snapshot. The corresponding grey scales show both the time (vertical axis)and height (horizontal axis) evolution. The dashed curve shows the corresponding smooth, steadyCAK model. Right: For 2DH+1DR SSF simulation, grayscale representation for the deviationsrendered as a time sequence of 2-D wedges of the simulation model azimuthal range ∆φ = 12o

stacked clockwise from the vertical in intervals of 4000 sec from the CAK initial condition.

to develop numerical radiation-hydrodynamics simulations of the resulting nonlinear evolution ofwind structure (Owocki, Castor & Rybicki 1988). A central challenge has been that the instabilityis strongest at scales near and below the Sobolev length (Owocki & Rybicki 1984), over whichwind ions are accelerated by their own thermal speed. This is typically of order a percent thestellar radius implying that simulations can’t use the local, Sobolev-based treatment of line-drivingthat is the basis for the standard CAK (Castor, Abbott & Klein 1975) model for steady-statewinds. A key breakthrough was the development (Owocki 1991; Owocki & Puls 1996) of theescape-probability-based “Smooth Source Function”(SSF) method that allows estimation of boththe direct and diffuse component of the line-force from a fixed set of profile-weighted columndepth integrals across the spatial grid. As illustrated in the left panels of figure 1, results of 1-D SSF simulations (Owocki 1991; Owocki & Puls 1999) show the instability does indeed lead tohighly nonmonotonic velocity outflow that compresses the wind into extensive clumps, boundedby embedded wind shocks (EWS) with velocity amplitudes (500-800 km/s), broadly consistentwith observed X-ray softness (∼ 0.5 keV) and luminosity scaling Lx ≈ 10−7Lbol (Owocki & Cohen1999). Modern observation of OB supergiants with the X-ray spectrographs on both Chandra andXMM/Newton do show wind-broadened X-ray emission lines that seem generally consistent withthis EWS picture (Owocki & Cohen 2001; Kramer, Cohen & Owocki 2003; Leutenegger et al. 2007).

The extensive clumped structure has important implications for determination of the wind massloss rate, which is central both to understanding the evolution and ultimate fate of massive stars,and to accounting for their feedback effects for the interstellar medium and stellar populationsin clusters. Mass loss rates rates typically inferred from recombination emission diagnostics (e.g.,Balmer emission near the star, and/or radio emission from outer wind) that scale with density-square, and so overestimate the mass loss rate in a clumped wind, by a factor set by the inversesquare-root of the clump volume filling factor, 1/

√fv. Radially extended 1-D SSF simulations by

2

Runacres & Owocki (2002, 2005) give fv ≈ 1/10, implying a potential factor 3 reduction in inferredmass loss rate; but both the inner-wind onset and outer-wind dissipation of this clumping dependon details, like the level of any base perturbation, or the outer region energy balance. These 1-Dsimulations also do not model the lateral scale and 3-D nature of actual clumps.

Since bound-free (b-f) absorption of X-rays scales linearly with density, it can provide a massloss diagnostic that is insensitive to wind clumping. Specifically, the shape and asymmetry ofX-ray emission line profiles resolved in OB supergiants by grating spectra from Chandra andXMM/Newton depend sensitively on the b-f absorption of X-rays emitted from the receding windof the back hemisphere. Our fitting (Kramer et al. 2003; Cohen et al. 2010) of the observed profileshape and asymmetry in several OB supergiants yields roughly the factor 3 reduction in mass lossimplied by instability simulations. However, if individual clumps become optically thick, the effec-tive masking of some material will reduce even the b-f absorption, thus making the wind “porous”.This can by itself reduce the profile asymmetry and so moderate or eliminate the inferred reductionin mass loss rate (Oskinova et al. 2004, 2007). Our analysis (Owocki and Cohen 2006) shows thatfor porosity to be important, the clump-to-clump mean-free-path or “porosity length”, set by thescale of clumps divided by their volume filling factor, must be comparable to the stellar radius.Given that the length scale of instabilities is only of order a percent of the stellar radius, this seemsunlikely. But further work is needed to constrain this porosity effect through direct application inexisting 1-D and future multi-D simulations of instability-generated structure.

Development of multi-D simulations of wind structure has so far been hindered by the need toprovide a suitably fast treatment of the inherently non-local radiation transport from line scattering(Owocki 1992; Owocki & Puls 1996, 1999). There have been limited attempts to use a simple 3-raytreatment to account for lateral forces and radiative transport along two oblique rays (Owocki 1999;Dessart & Owocki 2005a), while other efforts have mimicked multi-D structure by assigning time-randomized 1D simulations to fixed conical patches of with an assumed lateral angular scale (Dessart& Owocki 2002a,b), or used a “2DH+1DR” approach that accounts for full 2-D hydrodynamicalevolution, but limits the radiation transport to 1D along radial rays (Dessart & Owocki 2005b; seeright panel of fig. 1). Even these limited multi-D approximations have mainly been used to analyzevariability high S/N optical wind emission lines, with so far limited direct application to X-rays.

To build on the above semi-empirical results, there is a need now to carry out direct X-ray anal-yses using simulation models, for example to constrain porosity effects through direct application inexisting 1-D and future multi-D simulations of instability-generated structure. The structure andmass-loss rates of normal, single O star winds are inputs for our understanding of more extremeX-ray and gamma ray sources discussed in the next two subsections.

2.2 Colliding Wind Binary (CWB) systems

Massive stars often occur in binary systems, thus placing their winds in proximity for collisionalong a broad interaction front. The direct collision can result in shock velocities characterized bythe full wind flow speed (several 1000 km/s), thus leading again to X-ray emission that is muchharder (1-10 keV) than found from EWS. Early simulations of such Colliding Wind Binary (CWB)systems assumed a simple 2-D asymmetry that effectively fixes the orbital motion (e.g. Stevens,Blondin, & Pollock 1992). But advances in computing power have recently made possible the initialexploration of fully 3-D models that include orbital effects (Lemaster et al. 2007; Pittard 2009).

Members of our proposed team have been an active part of developing such 3-D simulationsand applying them to modeling of observational datasets of CWB systems. Under PI Owocki’ssupervision, UDel Ph.D. student Chris Russell has used 3-D Smoothed Particle Hydrodynamicssimulations to model the RXTE lightcurve of η Carinae in terms of wind absorption of a point-

3

spowocki

Cross-Out

log

ρ (g

cm

-3)

-10

-10

100

-55

x-y

Orb

ita

l P

lan

e

100

-55

t = -1d t = 202dt = 48d t = 1011d

x x x x

x-z

Ax

is P

lan

e

Figure 2: Snapshots of 3-D SPH simulation of wind-wind collision in η Car at times that, from leftto right, are -1, +48, +202, and +1,011 days from periastron. The color scale shows the density (ona logarithmic scale with cgs units) in the x-y orbital plane (top) and in the x-z perpendicular planecontaining the orbital and major axes (bottom). The X marks at the head of the wind-interactionfront makes the position of the assumed X-ray source. See Okazaki et al. (2008) for further details.

source of X-rays located at the head of the wind interaction front (Okazaki et al. 2008; see fig. 2.1);the good fit to the X-ray minimum that occurs near periastron of the highly eccentric (ǫ ≈ 0.9,5.5-year binary orbit) provides a tight constraint on the observer perspective, as well as other windand orbital parameters. Ph.D. research by another student in Owocki’s group, Tom Madura, aimsto use these and other 3-D simulations to model HST STIS slit spectra of η Carinae obtained atvarious orbital phases (Madura et al. 2009).

A key issue regards the potential role of radiative forces in modifying the hydrodynamicalcollision, including both the “radiative inhibition” (Stevens & Pollock 1994), by which radiationfrom each star weakens the initiation of the wind from its companion, and “radiative braking”, bywhich the radiation from the weaker-wind star slows or stops the incoming stronger wind from itscompanion (Gayley, Owocki, & Cranmer 1997). Analyses of the former effect have so far assumeda simple illumination model, but our subsequent studies (Owocki 2007) suggest that reflectionfrom the stellar photosphere can effectively cancel the radial component of the near-surface forcefrom impinging radiation. The latter effect was first suggested by Owocki & Gayley (1995) in thecontext of the short-period (4.2 day) WR+O binary system V444 Cygni, wherein it was shownthat such braking could prevent shock collapse from the strong WR wind onto the surface of theO-star, while also weakening the shock velocity and thus X-ray emission. Such radiative brakingeffects are most pronounced in close binary systems with highly asymmetric wind momenta, butour recent work (Tuthill et al. 2008) shows that they can even have significant influence on the windinteraction in wide, eccentric binaries, especially near periastron. The recent premature recoveryof the X-ray minimum seen in the latest orbital cycle monitoring of η Carinae by RXTE (Corcoranet al. 2010) suggests that such more effects, and not just simple wind absorption, may be neededto explain the sharp, extended X-ray minimum. Analogous issues hold for other CWB systems,

4

spowocki

Cross-Out

Figure 3: Left: Mass accretion vs. orbital phase in 3D SPH simulation of LS5039 (blue curve),compared to Bondi-Hoyle rate (red curve) computed from local variation of orbital and wind speedwithin the elliptical orbit. Right: γ-ray emissiom from LS5039, both for energies 0.1 − 10 GeVobserved by Fermi, and for energies > 1 TeV as observed by HESS. The red curve in the HESSplot is the best-fit sinusoid, produced during the initial data analysis. The blue curves are thepredicted phase variations from our simple Bondi-Hoyle accretion model, including the effects ofγ-γ absorption on the TeV gamma rays oberved by HESS.

e.g. WR 140. Next-generation hydrodynamics modeling is required for understanding propertiesof these extreme sources of massive-star high-energy emission, and radiation transport modeling isrequired to develop diagnostics of the high-energy processes.

2.3 X-rays and γ-rays from High-Mass X-ray Binaries (HMXB)

A yet more extreme setting for high-energy emission comes from the so-called High-Mass X-rayBinaries (HMXB), consisting of a massive OB star with a close compact companion (OB + cc),which can either be a neutron star or black hole. There are dozens of such systems, but an importantsubset (ca. half-dozen) also emit γ-rays, detected by Fermi at energies of 0.1-100 GeV, and/or byground-based Cerenkov telescopes (HESS, Veritas, Magic) at even higher energies, 100 GeV - 30TeV (see Holder (2009) for a recent review). Despite the modest number of detections so far,these binaries are of broad interest as stellar-scale laboratories for relativitic jets (connecting toAGNs) and particle acceleration (connecting to cosmic rays), since they are the only sources whereacceleration occurs with a range of different, but regularly repeating, environmental conditions. Incontrast to the Roche-lobe overflow believed to dominate for lower-mass systems, in HMXB thehigh-energy emission is generally thought to result from interaction of a dense stellar wind outflow(or in the case of the rapidly rotating Be stars, a circumstellar decretion disk; see below) with thecompact companion. But there are two quite distinct interaction mechanisms for producing thishigh-energy emission.

In analogy with the colliding wind models discussed above, the class of Pulsar-Wind-Shock(PWS) models envision again a strong shock collision of the massive-star wind outflow, but nowwith a relativistic pulsar pair-wind accelerated from a strongly magnetized neutron star (Dubus2008). Rather than producing primarily just the thermal X-rays from shock-heated plasma, Fermi

5

Wind

γ

BH

Z

Ψ

a

φ

θ

Figure 4: Left: Ilustration of accretion-jet interaction with a clumping stellar wind, wherein theresulting fluctuation in γ-ray emission can be characterized in terms of the porosity-length of windclumps. Right: Fluctuations in X-ray lightcurve with orbital phase in HD153919, which again canbe characterized by the porosity of the clumpy wind through which the X-ray emission propagates.

acceleration across the shock leads to highly relativistic populations of electrons and ions. The high-energy X-rays and gamma-rays can then be produced either through inverse Compton scattering ofstellar UV/optical radiation by the energetic electrons, or by collision of energetic ions with stellarwind protons, producing pions that quickly decay to gamma-rays.

An alterative MicroQuasar (MQ) scenario invokes Bondi-Hoyle Accretion of the massive-starwind onto a black hole or a non-magnetized (or only weakly magnetized) neutron star (Bosch-Ramon and Khangulyan 2009). The energy gained by accretion into the steep gravitational po-tential then powers energetic emission, either from an accretion cap, or from a jet of relativisticelectrons or ions, which again produce radiation via inverse Compton scattering by the electrons, orion-proton collisions to produce short-lived pions. While the relative merits of each paradigm havebeen extensively debated (e.g., Dubus 2006; Basch-Ramon et al. 2008), our team has undertakento examine both, e.g. through 3D smoothed particle hydrodynamics (SPH) simulations, tailoredfor the Be + cc binary LS I +61 303 ( et al. 2007). Although proponents of the PWS scenario havegenerally envisioned the pulsar pair-wind as interacting with a spherically symmetric stellar wind,the primary in LS I +61 303 is a Be star, in which the rapid stellar rotation leads to a fast, but quitelow-density polar wind, with the principle mass loss occuring instead via viscous diffusion througha dense equatorial “decretion disk”. This proves to be problematic for the PWS model, whereas theinteraction of the slow decretion disk with the compact object actually augments accretion onto thecc; indeed the phase variation found for the accretion rate in our simulations actually help explainthe observed concentration of TeV emission toward apastron.

During P.I. Owocki’s recent sabbatical fellowship in Japan, further work with co-I Okazakihas lead now to application of a Bondi-Hoyle accretion model to another TeV gamma-ray source,LS5039, which consists of a massive O6.5V star with a cc in a quite close, 3.9-day-period, mildlyelliptical (ǫ ≈ 0.25) orbit. By implementing Owocki’s methods for radiative driving into Okazkaki’sSPH simulation code, it is now possible, for the first time, to examine how the accretion rate isaffected by the radial variation of wind speed. Quite remarkably, the results, illustrated here in theleft panel of figure 3, show that the fully 3D dynamical simulation for the orbital phase variation

6

spowocki

Comment on Text

Okazaki et al. 2007)

of this accretion rate follows very closely the simple Bondi-Hoyle-Lyttleton (BHL) rate for thelocal radius and wind flow speed (Okazaki, Romero and Owocki 2008). This important new resultssuggests that models of the emission mechanism and global transport might be compartmentalizedfrom the full hydro simulation. The right panel of figure 3 shows results from a relatively simplemodel in which the intrinsic emission of X-rays and γ-rays is taken to track this accretion rate,but which accounts properly for the absorption of very-high-energy (VHE, i.e. TeV) radiationby γ-γ pair production from interaction with the stellar radiation. Note that the intrinsic BHLemission tracks quite well the phase variation observed by Fermi for the 0.1 − 10 GeV flux that isbelow the threshold for pair-production through interaction with stellar radiation; but the modelalso naturally reproduces quite well the orbital phase variation oberved by the HESS Cerenkovtelescope for the > 1 TeV radiation that is strongly affected by such γ-γ absorption!1

An additional focus of our prior research has been on the effect of the clumped structure ofstellar winds on the stochastic variability X-ray and γ-ray from HMXB. A recent analysis (Owockiet al. 2009) shows how the “porosity” formalism developed to study effect of wind clumps on X-rayscan also be used to characterize the statistical fluctuations in gamma-rays that would arise fromjet propagation through a highly clumped wind. Wind porosity can likewise help explain stochasticX-ray variations seen in HMXB systems like HD153919, as illustrated in the right panel of figure 4.

3 Proposed Research

Building on this background, we now propose a coordinated theoretical effort to develop and extenddynamical models for each of the three classes of wind-based high-energy emission from massivestars, as detailed in the following three subsections.

3.1 Radiation-Hydrodynamical Simulation of X-ray Emission and Absorption

We propose to apply and extend radiation hydrodynamical simulations of wind structure and shocksarising from the intrinsic instability of line-driving, to model the X-ray emission and absorption,with a goal to predict and interpret X-ray observational characteristics like energy distribution,emission line profiles, variability, and scaling of overall emission luminosity. These obervationalsignatures depend strongly on the key properites of the wind clump structure:

• Structure Scale: What sets the spectrum of spatial scales of wind structure? How is itinfluenced by base perturbations from atmospheric pulsation or turbulence, by stellar rotation,or by lateral coupling of diffuse radiation? In particular, under what circumstances can thescale be large enough to lead to a substantial porosity in b-f absorption of X-rays?

• Clumping Factor: What sets the magnitude and spatial distribution of the wind clumpingfactor? How is the onset affected by base perturbations, or by the details of treatment ofscattering line-drag? How does this affect Balmer emission used to infer mass loss? Likewise,what controls the outer dissipation of wind structure, and what are the implications for radiomass loss rates?

• Velocity Dispersion: What sets the magnitude and spatial variation of the wind velocitydispersion that leads to both compressed clumps and X-ray emitting shocks? What sets thephase relation between velocity and density fluctuations, and how does this influence theX-ray brightness and hardness?

1A paper detailing these very promising new results is currently in preparation, and will be uploaded for reviewers

to access at URL: http://www.bartol.udel.edu/ owocki/xfr/LS5039-BHAccretion.pdf.

7

spowocki

Cross-Out

Our initial efforts will focus on direct application of existing 1-D and pseudo-multi-D SSF simu-lations, with relatively modest extensions, e.g. to include base perturbations, and better resolutionof radiative cooling of shock-heated gas. Using methods developed in our empirical models, we willnow solve X-ray radiation transport of emission and absorption directly within snapshots of thesedynamical simulations, and use this to derive observational signatures like emission line spectrumand line profile shapes.

But dramatic advances in parallel computing capacity now make feasible multi-D treatments ofnonlocal radiation transport within a time-dependent hydrodynamical simulation. Taking advan-tage of this, we plan over the full term of the project to develop 2-D and eventually 3-D versions ofthese SSF simulations that take accurate account of the lateral line transport of scattered radiationalong along suitably fine set of rays. The goal is to study of how the associated lateral componentsdiffuse line-force couples wind structure. Unlike our previous 2DH+1DR approach that ignoressuch diffuse lateral transport and so tends to develop lateral variations down to the grid scale, thiscoupling could lead to a minimum lateral size, perhaps comparable to the ca. 1 degree scale inferredby our empirical fits to optical emission line variations (Dessart & Owocki 2002a, 2005a).

As noted in §2.1, the results have broad implications for X-ray emission and transport, includingthe role of porosity in reducing b-f absorption. The properties of wind structure can also have astrong influence on the X-ray emission from CWB shocks, and γ − ray emission in HMXB, asdiscusseed next.

3.2 Effect of Clumping & Radiative Forces on CWB Shocks

Building on our existing work on 3-D hydrodynamical simulations of CWB, our further simulationswill incorporate a generalized CAK/Sobolev treatment of radiative driving from each of the twocompanion stars, allowing proper account of the each wind’s radiative acceleration against gravity,as well as of the mutual influence of the radiation of the companion star on the other star’s wind,including both the radiative inhibition (Stevens and Pollack 1994) and radiative braking (Gayley,Owocki, & Cranmer 1997) effects. Specific questions are:

• Shock Reduction and Collapse: How does incorporation of wind acceleration alter the formand strength of the shock interaction front. What are the conditions for shock collapse in caseswhere the ram balance brings the stronger wind past the point of maximum momentum fluxfor the weaker wind? In an eccentric binary how does such collapse start and end as the starsapproach and recede on each side of periastron? Could this provide an explanation for theextended, and now variable, X-ray minimum observed from η Carinae by RXTE (Corcoranet al. 2010).

• Clumping and Porosity: How does the clumped nature of the winds effect CWB shocks? Howdoes this depend on the porosity length? Can shock interpenetration and mixing also leadto shock collapse, especially when coupled to cooling? Is observed X-ray flickering linked toinstrinsic wind clumping, or to thin-shell instabilities at the interface?

• Radiative Braking and Inhibition: How are the shock interaction, and indeed the nature andoperation of shock collapse, affected by braking of the stronger wind by the radiation ofthe weaker-wind star? Can observational signatures of radiative braking in WR+O binariesbe used to constrain the effective opacity of WR winds? Similarly, how are these windinteractions affected by inhibition of the initial acceleration of each wind by the radiation ofits companion? How does each star’s photospheric reflection of the companion’s light alter thesimple, pure-illumination formulation used in the standard analysis of radiative inhibition?

8

spowocki

Cross-Out

Would the expected cancellation of the near-surface normal component of any external force(cf. Owocki 2007) effectively “inhibit” any radiative inhibition? What are the implicationsfor modeling X-ray lightcurves, especially around X-ray minimum?

The basic methods and codes for implementing radiation forces in CWB simulation codes wereinitially developed from our earlier analyses of radiative braking (Owocki & Gayley 1995; Gayley,Owocki & Cranmer 1997). The initial phase our project will thus focus on comparison and synthe-sizing the two approaches, along with generalizations to include reflection. Implementation in ourcombined suite of 3-D codes (both SPH and finite-difference based) should be straightforward.

3.3 Dynamical Models of X-rays and γ-rays from HMXB

Building on the promise of our prior efforts outlined in § 2.3, we now propose to extend ourdynamical simulations of X-ray and γ-ray emission in HMXB, with emphasis on the followingissues:

• Pulsar-wind vs. Microquasar: What are the relative merits and shortcomings of the pulsar-wind-shock (PWS) vs. microquasar (MQ) accretion jet models for γ-ray emission in the 3 keysystems: LS5039, LS I +63 303, and PSR B1259-63.

• Be Decretion Disk vs. Stellar Wind: In the latter two systems, the primary is actually aBe star, with circumstellar material from the decretion disk dominating that from the stellarwind, which itself has a strong latitudinal dependence. This distinction has been often beenoverlooked in models by high-energy specialists, who have generally focused on details ofthe high-energy emission, based on an idealized view of the primary mass loss as being in aconstant speed, spherically symmetric stellar wind. Of the above 3 systems, PSR B1259-63 isthe only one exhibiting clear pulsar signatures, and so seems the strongest candidate for thePWS model; but reliable predictions of the high-energy emission and its variation with phasemust be based on a realistic treatment of the interaction geometry between the pulsar-windand the primary’s non-spherical circumstellar material, which our 3D dynamical simulationswill provide.2

• Wind Acceleration: Even within the context of non-Be case LS5039, for which the mass lossis indeed expected to be from a nearly spherical stellar wind, most previous studies haveassumed a fixed wind outflow speed, ignoring the fact that, for the close separation (semi-major axis only about 3 stellar radii) involved, the cc lies well within the expected accelerationregion for the stellar wind. Building on our recent models that account for wind accelerationin the context of BHL accretion in the MQ model, we now plan to examine its importance fora PSR model of LS5039, to test whether the expected orbital phase variations can naturallymatch the Fermi and HESS lightcurves as well as the MQ results shown in figure 3.

• Photon Cascade and Energy Spectrum: Although our simple Bondi-Hoyle accretion modelwith photon-photon absorption matches quite well the Fermi and HESS light curves forLS5039, it does not explain the inferred energy distribution. The higher cross section at lowerenergies near but above pair-production threshold implies there should be spectral hardeningat the TeV flux minimum, whereas the HESS observations indicate instead a relative soft-ening. Our future efforts will examine whether this spectral softening could be the result of

2A focus on PSR B1259-63 is particularly timely, since the system has a 3.4 year orbit, which with solar positioning

means ground visibility near periastron occurs only every 7 years or so. The next periastron, December 15, 2010, will

be the first since the launch of Fermi, spurring many supporting multiwavelength observing campaigns.

9

photon cascade, wherein energy lost from absorpton of higher-energy (> 1 Tev) photons isre-emitted as softer photons. To match the sharp cutoff at ∼ 10 GeV, which about a factor10 below the energy threshold for γ-ray interaction with stellar UV radiation, we also plan toinvestigate the role of X-rays from accretion region in the attenuation of 10-100 GeV γ-rays.

• Wind Clumping and Porosity: Finally, building on our previous analysis of how wind porositycan lead to stochastic variations in γ-ray emission, we now plan to apply the specific clump-ing and porosity characteristics derived from wind-instability simulations decribed in §§2.1and 3.1. We plan also to use observed X-ray lightcurves from HMXB to infer the porosityproperties of the primary star’s wind.

An overall theme here is that since the discovery of VHE γ-ray emission from HMXB, much ofthe emphasis of theoretical models has been on the details of the high-energy emission, assuminga fixed paradigm, most commonly PSW, without much attention to the nature of mass loss fromthe primary. By contrast, the broad range of expertise of our investigator team allows for morecomprehensive approach that balances treatments of high-energy emission and transport processwith realistic 3D hydrodynamical models of non-spherical, often highly clumped, mass loss frommassive-star primary.

3.4 Simulation Codes

Building on our prior research, the various studies in this project make broad use of numericalhydrodynamics simulations, with both Smooth Particle Hydrodynamics (SPH) codes and finite-difference, grid-based codes. The SPH code is based on a version first introduced by Benz (1990),and developed further by Bates et al. (1995). Subsequent extensions by collaborator Okazakiinclude implementation on massively parallel supercomputers (first in Japan, but working withOwocki’s graduate student C. Russel, more recently also those at NASA GSFC). This make itfeasible to carry out fully 3D simulations for cases that are difficult to model with grid-based codes,e.g. colliding winds in highly elliptical binaries like eta Carinae. On the other hand, the smoothingand artificial viscosity of SPH codes makes them ill-suited for studying small-scale structure. Assuch, our simulations of the line-deshadowing instability use instead high-order finite-differencecodes like VH-1 (developed by J. Blondin), which uses the PPM method with a Godunov solverto resolve shocks. In addition, MHD codes like Zeus or Athena3, which we originally adopted tostudy magnetically chanelling of hot-star winds (e.g. ud-Doula & Owocki 2002), can also be readilyrun in pure hydro mode. Through operator splitting, all these finite difference codes can be run inone, two, or three dimensions, with cartesian or spherical grids. In practice, 3D operation requiresimplementation on parallel clusters, which is a focus of current implementation by us and others.Overall, there are many publicly available options for codes to carry out basic hydrodynamics, andmuch our detailed effort has been toward implementing extension for including radiative driving.

4 Personnel & Work Plan

4.1 Qualifications and Expected Contributions of Investigators

Although very ambitious, the project here builds quite directly on our prior research, combiningthe varied experience and expertise of the proposed investigators. PI Owocki has worked for morethan 20 years on the physics of radiatively driven mass loss, with extensive experience in all 3 ofthe targeted mechanisms for high-energy emission; the basic methods used and codes developed in

3http://www.astro.princeton.edu/ jstone/athena.html

10

spowocki

Comment on Text

makes

that work will form the basis for the analysis and modeling efforts proposed here. He will lead,guide, and coordinate the overall project.

Co-I Cohen was also a former post-doc in Owocki’s group at UDel, focused on applying Owocki’ssimulation results toward empirical analyses of intrinsic X-rays from single OB stars. Since joiningthe faculty at nearby Swarthmore College, he and Owocki have maintained a very active collabo-ration, highlighted also by his remarkable success in supervising multiple undergraduate researchprojects (see §5.3). Working with future students, Cohen plans to focus efforts on guiding theapplication of instability simulations to interpretation of X-ray emission lines.

Co-I Holder works on the Veritas Cerenkov telescope for TeV gamma-ray sources, and also hasa broad background in observations by orbiting gamma-ray telescopes. In summer 2009, he andOwocki co-supervised research by UDel junior undergraduate Dan Hertenstein supported througha summer fellowship from NASA’s Delaware Space Grant College consortium. The project com-bined a theoretical effort with Owocki to extend porosity models to include a power-law clumpdistribution, and observational analyses with Holder to examine variability of Veritas sources inX-ray wavebands. Holder’s contribution to the project here will be to coordinate comparisons ofthe theoretical models of HMXB systems with available gamma-ray datasets.

Collaborator Okazaki has extensive experience applying 3D SPH simulations, e.g. to Be de-cretion disk and Be X-ray binaries, and colliding winds. He will continue his work with Owockito carry out dynamical simulations of both the pulsar-wind-shock and mass-accretion models forpowering X-ray and γ-ray emission in HMXB.

Collaborator Romero has worked extensively on high-energy emission mechanisms for bothgalactic and extra-galactic sources. Building upon previous work with Owocki and Okazaki, he willguide the application of specific high-energy emission mechansims to the hydro models, includingthe treatment of photon cascades to reproduce the inferred hardness ratios and energy distibutions.

Collaborator Corcoran has broad experience with X-ray datasets, and has already worked PIOwocki and his group on topics in this proposal. He is currently NASA-center advisor on theGSRP fellowship funding UDel Ph.D. student, Chris Russell, whose thesis also includes analysisCWB X-rays. Together with Cohen and Holder, he will provide an observational perspective toensure that the theoretical results are well-positioned to augment interpretation of both targetedand survey observation of massive stars, with particular emphasis on analysis of the recent largeChandra survey of the Carina region (PI L. Townsley).

4.2 Work Plan

Within the caveat that the most fruitful research often comes about from following interesting newavenues arising from intermediate results, we offer the following general outline of our time planfor carrying out our proposed project:

• Year 1: Begin initial implementations in all 3 areas. For EWS, apply existing SSF simulationsto analyze porosity effects on X-ray emission lines; led by co-I Cohen, working with PI andnewly recruited undergrad and/or grad students. For CWB, incorporate radiative drivingand implement reflection effect modifications; led by post-doctoral researcher. For HMXB,carry out SPH sims of effect of non-spherical mass loss on γ-ray models, and of role photoncascades in energy spectrum of LS5039. Led by Okazaki, with input from Romano on cascade,and Holder on data modeling, with likely involvement also of students and/or post-doc.

• Year 2: Extend above and add emphasis on longer-term challenges. For EWS, develop 2-D SSF incorporating lateral diffuse force; led by PI Owocki, working with post-doc andpossibly new grad student. For CWB, compute 3-D models and derive X-ray light curves,

11

with emphasis on radiative force effects in softening or quenching emission around periastron.For HMXB, testing of relative merits of PWS vs. MQ models for 3 target systems.

• Year 3: Full operation of 3 topics, but with added emphasis on forging theory advancesinto suite of diagnostic signatures for application in separate analysis efforts for targeted andsurvey observations; theory efforts as above, with heavy input from observational collaboratorsCohen, Holder, and Corcoran.

5 Broad Relevance of Proposed Project

5.1 Massive Stars

Massive stars are powerhouses of the galaxy, with broad influence on the mass and energy budgetof the interstellar medium, especially in young, star forming regions. In the context of the currentproposal, some particular items of broad relevance include:

• Mass Loss: This is a key to both the evolution of the star’s themselves, and the surroundingcircumstellar and interstellar medium. As such, there is vital need for accurate determinationsof mass loss rate that minimize or account for wind clumping, as provided by the b-f X-rayabsorption and associated simulation models proposed here. Our fundamental simulationsof massive-star wind driving moreover serve as a prototype for key dynamical processes inother luminous systems, such as winds from luminous accretion disks around both stellar orsupermassive central objects.

• Binarity: Massive stars occur commonly, even predominantly, in binary (or still higher mul-tiple) systems, and this has important implications for understanding their formation andevolution. CWB of type O+O and O+WR provide snapshots of an evolutionary stage beforethe more massive star explodes as supernova, leaving behind a compact companion seen inhigh-mass mass-transfer systems. In some key examples, e.g. η Carinae, the primary evidencefor presence of a high-mass secondary (which is still not clearly detected directly) is in factthrough the clock-like, periodic variation in X-ray emission. Our study of CWB X-rays ispart of a broader effort to understand the incidence, properties, and consequences of binarityin massive stars, while the focus on radiative forces in such collisions provides a novel varianton their role in stellar and disk wind driving.

• Shocks: Shocks are fundamental and pervasive by-products of interactions in hypersonic astro-physical flows. The 3 specific examples studied here provide a varied laboratory of conditionsand characteristics for determining the X-ray signatures of resulting shock properties. Assuch, the results and analysis methods here share a broad relevance for studies of many othertypes of astrophysical shocks.

• X-rays as Beacons: Moreover, the relative penetration of X-rays through many magnitudes ofvisible interstellar extinction makes them effective beacons of massive stars in distant reachesof the Galaxy, or in young, active star-forming regions. The proper identification of massivestars in X-ray surveys, in particular determining the type of source, depends on predictionsfrom the associated theoretical models in this study.

5.2 Impact on current and future NASA missions

Our project will have a significant aspect in the interpretation of data from nearly all importantNASA missions, highlighted as follows:

12

• Chandra and XMM imaging data. The theoretical developments we propose here haveparticular significance for interpretation of X-ray emission (luminosities and spectra) fromlarge surveys carried out by Chandra and XMM/Newton, especially in important regions ofmassive star formation in the Milky Way and other nearby galaxies (the LMC, SMC andM31 in particular). One prime exampleis the Chandra Very Large Program to survey theCarina Nebula star forming region, home to many of the most massive stars known andprobable home to the next Galactic hypernova. This has resulted in the detection of morethan 14,000 stellar sources, including hundreds of known OB stars. The massive star X-raydata will provide the first census of X-ray emission from unevolved massive OB stars alongwith emission from massive evolved WR stars. Our modeling work may help determine thedistribution of massive colliding wind binaries, which has important implications on the binaryfraction. Theoretical understanding of the importance of radiative braking, and emission fromwind-wind collisions, are crucial to understanding the survey data and to determining howX-rays from massive stars help shape the circumstellar environment both dynamically andradiatively. Collaborator Corcoran is leading the analysis of the X-ray emission from massivestars and Owocki and Cohen are invited collaborators in the data analysis and modeling ofthe survey data. Our modeling is likewise imporantant for other Chandra surveys, such asthat covering the Cygnus OB association (Wright and Drake 2009).

• Dynamics from X-ray Line Profiles. The best diagnostic of the dynamics of the strongflows associated with OB and WR single and binary stars are the profiles of strong, re-solved X-ray emission lines. Such profiles constrain the flow geometry, and (for the He-likelines) provide important information about densities, temperatures, and the local ionizingradiation. A handful of bright, important massive stars have already been observed at highresolution by the gratings on Chandra and XMM/Newton. Upcoming observations with theX-ray calorimeters on ASTRO-H and the International X-ray Observatory (IXO) will greatlyincrease the number of massive stars that can be observed at high spectral resolution. Real-istic, 3-D models of the wind outflows of the kind we can provide are needed in order to teaseout the flow geometry and mass and radiation densities from the line profiles.

• X-ray Variability. Variability is most common in CWBs due to orbital or rotational mo-tion. Variability can be modelled using data from RXTE, ROSAT, ASCA, XMM/Newton,Chandra, Suzaku, Swift and upcoming missions like ASTRO-H and IXO. Understanding thephysical mechanisms producing the variability requires detailed 3-D models including subtleeffects like radiative braking that is a focus of our theory study.

• Spatially-resolved Spectra of Circumstellar Nebulosity. HST/STIS observations ofcircumstellar nebulosity around η Car provide a unique, 3-D view of the variable emissionproduced by the central binary star. There is currently active application of our CWBsimulations of η Car to the Treasury Project data on HST, centered on UDel Ph.D. studentT. Madura’s thesis project to model the slit spectra accounting for the time-variable windinteraction fronts.

• VHE Astrophysics and Cosmic Rays. HMXB with VHE γ-ray are of broad interest asstellar-scale laboratories for relativitic jets (connecting to AGNs) and particle acceleration(connecting to cosmic rays), since they are the only sources where acceleration occurs with arange of different, but regularly repeating, environmental conditions. As such they provide abasis for understanding a broad range of sources observed by orbiting gamma-ray telescopeslike NASA’s Swift, and Fermi satellites, and the European Integral and AGILE missions.

13

5.3 Education and Training Impact

A prominent feature of both past and planned research in our group is the heavy emphasis oneducation and training of both undergraduate and graduate students, as well as post-doctoral re-searchers. Owocki is currently supervising 3 Ph.D. students (Tom Madura, Chris Russell, and MaryOksala), all of whom have existing fellowship or other support lines, and all of whose theses arethematically related to this proposal. In addition to above-noted co-advising of the summer under-graduate research by Dan Hertenstein on gamma-rays, Owocki, together with UDel Professor MikeShay, recently helped supervise a successful honors thesis by UDel undergraduate student, ChrisBard, in this case to use Shay’s reconnection codes to study simplified representations centrifugallydriven reconnection found by Owocki and collaborators in models of massive-star magnetospheres(ud-Doula, Owocki, and Townsend 2008).

Since joining the faculty at nearby Swarthmore College in fall of 2000, co-I Cohen (who waspreviously a post-doc with Owocki at UDel) has been even more active and successful in mentoringundergraduate students and supervising multiple student research projects. For example, recentgraduates Erin Martell and Emma Wollman contributed key analyses on X-rays from EWS, and arenow continuing graduate studies at U. Chicago and Caltech; Wollman’s project was even a finalistfor prestigious APS Aker award. Overall, Cohen has an impressive list of 9 refereed journal papersco-authored with students over the past 6 years; his Vita gives further details. Two other recentpost-docs in Owocki’s group, R. Townsend and A. ud-Doula, have also moved on to tenure trackfaculty postions (respectively at U. Wisconsin Madison and Penn State Scranton)4. An earlierpost-doc, K. Gayley, is now a professor at University of Iowa.

Continuing this extensive record of undergraduate, graduate, and post-doctoral research trainingis an important component of this proposal. We propose to support one undergrad summer researchproject per year, recruited either from UDel or Swarthmore, to work on development of theoreticalmodels into observational diagnostics. We also propose full-time support for a new graduate studentto begin thesis research in one of the 3 focused model areas. Finally, a major focus is on thetraining of a new post-doctoral researcher in theoretical and simulation modeling of massive-starX-rays and/or γ-rays, and their application for interpreting associated high-energy datasets. Suchongoing training helps fulfill and sustain a central need for qualified young researchers to analyzeand interpret the wealth of existing and future data from a range of NASA missions.

4Townsend is PI on a complementary but fully independent, Wisconsin-based ATP proposal to study massive-star

magnetospheres, with ud-Doula as co-I, and Owocki participating as a collaborator.

14

References

Bate M.R., Bonnell I.A. & Price N.M. 1995, MNRAS 277, 362Benz W. 1990, in Buchler J. R., ed., The Numerical Modelling of Nonlinear Stellar Pulsations,

Kluwer, Dordrecht, p.269.Bosch-Ramon, V., Khangulyan, D., & Aharonian, F. A. 2008, American Institute of Physics Con-

ference Series, 1085, 223Bosch-Ramon, V. and Khangulyan, D. 2009, International Journal of Modern Physics D ’18, 347Castor, J. I., Abbott, D. C., & Klein, R. I. 1975, ApJ, 195, 157Cohen, D. H., Leutenegger, M. A., Wollman, E. E., Zsargo, J., Hillier, D. J., Townsend, R. H. D.,

& Owocki, S. P. 2010, MNRAS, 603, in press.Cranmer, S. R., & Owocki, S. P. 1995, ApJ, 440, 308Dessart, L., & Owocki, S. P. 2002a. A&A, 383, 1113.Dessart, L., & Owocki, S. P. 2002b. A&A, 393, 991.Dessart, L., & Owocki, S. P. 2005a, A&A, 432, 281Dessart, L., & Owocki, S. P. 2005b, A&A, 437, 657Dubus, G. 2006, A&A, 456, 801Dubus, G. 2008, New Astronomy Reviews, 51, 778Gagne, M., Oksala, M. E., Cohen, D. H., Tonnesen, S. K., ud-Doula, A., Owocki, S. P., Townsend,

R. H. D., & MacFarlane, J. J. 2005, ApJ, 628, 986Gayley, K. G., Owocki, S. P., & Cranmer, S. R. 1997, ApJ, 475, 786Gull, T., Nielsen, K., Corcoran, M, Madura, T., Owocki, S., Russel, C., Hillier, D.J., Hamaguchi,

K., Kober, G., Weis, K., Stahl, O., & Okazaki, A.T. 2009, MNRAS, in press.Holder, J. 2009, arXiv:0912.4781Kramer, R. H., Cohen, D. H., & Owocki, S. P. 2003, ApJ, 592, 532Lemaster, M. N., Stone, J. M., & Gardiner, T. A. 2007, ApJ, 662, 582Leutenegger, M. A., Owocki, S. P., Kahn, S. M., & Paerels, F. B. S. 2007, ApJ, 659, 642Lucy, L. B., & Solomon, P. M. 1970, ApJ, 159, 879Madura, T., Gull, T., Owocki, S., Okazaki, A., & Russell, C. 2009, Bulletin of the American

Astronomical Society, 41, 205Mullan, D. J. 1984, ApJ, 283, 303Okazaki, A. T., Romero, G. E., & Owocki, S. P. 2008, Proceedings of the 7th INTEGRAL Work-

shop, arXiv:0811.1958v1Okazaki, A. T., Owocki, S. P., Russell, C. M. P., & Corcoran, M. F. 2008, MNRAS, 388, L39Oskinova, L. M., Feldmeier, A., & Hamann, W.-R. 2004, A&A, 422, 675Oskinova, L. M., Hamann, W.-R., & Feldmeier, A. 2007, A&A, 476, 1331Owocki, S. P., & Rybicki, G. B. 1984, ApJ, 284, 337Owocki, S. P., & Rybicki, G. B. 1985, ApJ, 299, 265Owocki, S. P., Castor, J. I., & Rybicki, G. B. 1988, ApJ, 335, 914Owocki, S. P. 1991, NATO ASIC Proc. 341: Stellar Atmospheres - Beyond Classical Models, 235Owocki, S. P. 1992, Nonisotropic and Variable Outflows from Stars, 22, 273Owocki, S. P., & Gayley, K. G. 1995, ApJL, 454, L145Owocki, S. P., & Puls, J. 1996, ApJ, 462, 894Owocki, S. P. 1999, IAU Colloq. 169: Variable and Non-spherical Stellar Winds in Luminous Hot

Stars, 523, 294Owocki, S. P., & Puls, J. 1999, ApJ, 510, 355Owocki, S. P., & Cohen, D. H. 1999, ApJ, 520, 833Owocki, S. P., & Cohen, D. H. 2001, ApJ, 559, 1108

1

Owocki, S. P., & Cohen, D. H. 2006, ApJ, 648, 565Owocki, S. 2007, Massive Stars in Interactive Binaries, 367, 233Owocki, S. P., Romero, G. E., Townsend, R. H. D., & Araudo, A. T. 2009, ApJ, 696, 690Parkin, E. R., & Pittard, J. M. 2008, MNRAS, 388, 1047Parkin, E. R., Pittard, J. M., Corcoran, M. F., Hamaguchi, K., & Stevens, I. R. 2009, MNRAS,

394, 1758Pittard, J. M., & Dougherty, S. M. 2006, MNRAS, 372, 801Pittard, J. M. 2009, arXiv:0904.0164Pittard, J. M. 2009, arXiv:0905.3315Romero, G. E., Okazaki, A. T., Orellana, M., & Owocki, S. P. 2007, A&A, 474, 15Runacres, M. C., & Owocki, S. P. 2002, A&A, 381, 1015Runacres, M. C., & Owocki, S. P. 2005, A&A, 429, 323Stevens, I. R., Blondin, J. M., & Pollock, A. M. T. 1992, ApJ, 386, 265Stevens, I. R., & Pollock, A. M. T. 1994, MNRAS, 269, 226Stone, J. M., Gardiner, T. A., Teuben, P., Hawley, J. F., & Simon, J. B. 2008, ApJS, 178, 137Tavani, M., et al. 2009, arXiv:0904.2736Tuthill, P. G., Monnier, J. D., Lawrance, N., Danchi, W. C., Owocki, S. P., & Gayley, K. G. 2008,

ApJ, 675, 698ud-Doula, A., & Owocki, S. P. 2002, ApJ, 576, 413Ud-Doula, A., Owocki, S. P., & Townsend, R. H. D. 2008, MNRAS, 385, 97Wright, N. J., & Drake, J. J. 2009, ApJS, 184, 84

2

Biographicial Sketch: P.I. Stanley Peter Owocki, Professor

Bartol Research Institute, Department of Physics & Astronomy,

University of Delaware, Newark, DE 19716

(302)-831-8357; [email protected]; www.bartol.udel.edu/∼owocki/

Ph.D. 1982, Astrophysics, U. of Colorado; B.S 1973, Biophysics, Brown U.

DOB: 1951.12.15; Married, 3 Children

Member AAS; IAU; IAU Working Group on Massive Stars

Employment:

• 9/99-present: Bartol Research Institute, U. Del., Professor

• 9/91-8/99.:Bartol Research Institute, U. Del., Assoc. Prof.

• 10/87-8/91.:Bartol Research Institute, U. Del., Assist. Prof.

• 1/84-9/87: UCSD/CASS, Research Physicist.

• 12/81-1/84: Harvard-Smithsonian CfA, Langley-Abbott Fellow.

• 9/79-11/81: High Altitude Observatory/NCAR, Grad. Res. Asst.

Research Interests:

• dynamics of radiatively driven flows from stars and accretion disks

• massive-star magnetospheres

• computational radiation-hydrodynamics and magnetohydrodyanmics

• structure and dynamics of solar corona and wind

Ph.D. Students:

1. R. Glenn Cooper, 9/89-6/94 (now Support Scientist, Fermilab)

2. Steven Cranmer, 9/92-8/96 (now Res. Sci., Harvard-Smithsonian CfA)

3. Asif ud-Doula, 9/98-9/02 (now Asst. Prof., Penn State Scranton)

4. Tom Madura, 9/03-pres. (expected Ph.D. Aug. 2010)

5. Mary Oksala, 9/04-pres. (expected Ph. D. June 2011)

6. Chris Russel, 9/06-pres. (expected Ph. D. August 2011)

Post-Doc/Research Scientist Supervision:

1. Alex Fullerton, 12/89-4/94 (now JWST Support Scientist, JHU)

2. Ken Gayley, 11/92-8/97 ( now Assoc. Prof., U. Iowa)

3. David Cohen, 9/98-5/00 (now Assoc. Prof., Swarthmore Coll.)

4. Vikram Dwarkadas, 11/00-9/0 (now Res. Sci., U. Chicago)

5. Richard Townsend, 8/03-8/08 (now Asst. Prof., U. Wisc)

6. Asif ud-Doula, 9/05-1/08 (now Asst. Prof., Penn State Scranton)

7. Allard-Jan van Marle, 9/06-8/08 (now Res. Sci., U. Leuven, Belgium)

Book Edited

Instability and Variability in Hot Star Winds, Proceedings of workshop held in August 1993 on

the Isle-aux-Coudre, Quebec, Canada. A. Moffat, S. Owocki, A. Fullerton, and N. St-Louis,

eds., (Kluwer: Dordrecht), 1995; also published as Astrophysics & Space Science, vol. 221.

Enclyclopedia article: Winds from Hot Stars, Encyclopedia of Astronomy and Astrophysics,

Institute of Physics Publishing, Nature Publishing Group, MacMillan.

Relevant Selected Publications over Past 6 Years

1. Owocki, S. P.; Romero, G. E., Townsend, R. H. D., Araudo, A. T. “Gamma-Ray Variability from WindClumping in High-Mass X-Ray Binaries with Jets”,Astrophysical Journal, 696, 609

2. Skinner, S. L., Sokal, K. R., Cohen, D. H., Gagne’, M., Owocki, S. P.,Townsend, R. D., 2008, “High-Resolution Chandra X-Ray Imaging and Spectroscopy of the sigma Orionis Cluster”,Astrophysical Journal,683, 796

3. Okazaki, A. T., Owocki, S. P., Russell, C. M. P., Corcoran, M. F., 2008, “Modelling the RXTE light curve ofη Carinae from a 3D SPH simulation of its binary wind collision”,Monthly Notices of the Royal AstronomicalSociety, 388, L39

4. Tuthill, P. G., Monnier, J. D., Lawrance, N., Danchi, W. C., Owocki, S. P., Gayley, K. G., 2008, “ThePrototype Colliding-Wind Pinwheel WR 104”,Astrophysical Journal, 675, 698

5. Romero, G. E., Okazaki, A. T., Orellana, M., Owocki, S. P., 2007, “Accretion vs. colliding wind models forthe gamma-ray binary LS I +61 303: an assessment”,Astronomy and Astrophysics, 474, 15

6. Madura, T. I., Owocki, S. P., Feldmeier, A., 2007, “A Nozzle Analysis of Slow-Acceleration Solutions inOne-dimensional Models of Rotating Hot-Star Winds”,Astrophysical Journal, 660, 687

7. Leutenegger, M. A., Owocki, S. P., Kahn, S. M., Paerels, F. B. S., 2007, “Evidence for the Importance ofResonance Scattering in X-Ray Emission Line Profiles of the O Star zeta Puppis”, Astrophysical Journal,659, 642

8. Romero, G. E., Owocki, S. P., Araudo, A. T., Townsend, R., 2007, “Gamma-ray emission from jet-clumpinteraction”,Boletin de la Asociacion Argentina de Astronomia La Plata Argentina, 50, 319

9. Orellana, M., Romero, G. E., Okazaki, A. T., Owocki, S. P., 2007, “Theaccretion mass regimes in thegamma-ray binary LS I +61o 303”, Boletin de la Asociacion Argentina de Astronomia La Plata Argentina,50, 311

10. Owocki, S. P., Cohen, D. H., 2006, “The Effect of Porosity on X-Ray Emission-Line Profiles from Hot-StarWinds”, Astrophysical Journal, 648, 565

11. Cohen, D. H., Leutenegger, M. A., Grizzard, K. T., Reed, C. L., Kramer, R. H., Owocki, S. P., 2006, “Windsignatures in the X-ray emission-line profiles of the late-O supergiant zeta Orionis”, Monthly Notices of theRoyal Astronomical Society, 368, 1905

12. Dessart, L., Owocki, S. P., 2005, “2D simulations of the line-driven instability in hot-star winds. II. Approx-imations for the 2D radiation force”,Astronomy and Astrophysics, 437, 657

13. Runacres, M. C., Owocki, S. P., 2005, “A pseudo-planar, periodic-box formalism for modelling the outerevolution of structure in spherically expanding stellar winds”,Astronomy and Astrophysics, 429, 323

14. Owocki, S. P., Gayley, K. G., Shaviv, N. J., 2004, “A Porosity-Length Formalism for Photon-Tiring-limitedMass Loss from Stars above the Eddington Limit”,Astrophysical Journal, 616, 525

15. Antokhin, I. I., Owocki, S. P., Brown, J. C., 2004, “A Steady, Radiative-Shock Method for Computing X-RayEmission from Colliding Stellar Winds in Close, Massive-Star Binaries”,Astrophysical Journal, 611, 434

16. De Becker, M., Rauw, G., Pittard, J. M., Antokhin, I. I., Stevens, I. R., Gosset, E., Owocki, S. P., 2004, “AnXMM-Newton observation of the massive binary HD 159176”,Astronomy and Astrophysics, 416, 221

2

DAVID H. COHEN

EDUCATION

University of Wisconsin-Madison Ph.D. in Astronomy, 1996, “High-Energy Emission from B Stars and Its Relationship to Stellar Winds,” under the direction of Prof. Joseph Cassinelli

Harvard College A.B. in Astronomy and Astrophysics, magna cum laude, 1991, senior honors thesis, “Disentangling Double-Line Spectroscopic Binaries,” under the direction of Dr. David Latham

EMPLOYMENT

Associate Professor Swarthmore College, 2006–present Assistant Professor Swarthmore College, 2000–2006 Research Scientist Bartol Research Institute, University of Delaware and Prism Computational

Sciences 1998–2000 Post-doc, Assistant Scientist Fusion Technology Institute and Astronomy Department,

University of Wisconsin-Madison, 1996–1998

RESEARCH INTERESTS X-ray spectroscopy and numerical modeling of hot plasmas in laboratory and astrophysical

settings Stellar winds high-energy observations, analysis, and modeling X-ray/EUV astronomy spectral analysis, time-variability analysis, hot stars, young stars Laboratory astrophysics modeling, spectroscopy, and experiment design of x-ray photoionized

plasmas; plasmas heated by magnetic reconnection Inertial confinement fusion experiment design and modeling

SELECTED PUBLICATIONS Leutenegger, Cohen, Zsargo, Martell (’09), MacArthur (’11), Owocki, Gagne, & Hillier

“Modeling Broadband X-ray Absorption of Massive Star Winds,” 2010, Ap.J., submitted Cohen, Leutenegger, Wollman (’09), Zsargo, Hillier, Townsend, & Owocki, “A Mass-Loss

Rate Determination for ζ Puppis from the Quantitative Analysis of X-ray Emission Line Profiles,” 2010, MNRAS, in press

Chaplin (’07), Brown, Cohen, Gray, & Cothran, “Spectroscopic Measurements of Temperature and Plasma Impurity Concentration During Magnetic Reconnection at the Swarthmore Spheromak Experiment,” 2009, Physics of Plasmas, 16, 042505

Cohen, Kuhn (’07), Gagne, Jensen, & Miller, “Chandra Spectroscopy of the Hot Star β Crucis and the Discovery of a Pre-Main-Sequence Companion,” 2008, MNRAS, 386, 1855

Leutenegger, Paerels, Kahn, & Cohen, “Measurements and Analysis of Helium-Like Triplet Ratios in the X-ray Spectra of O-Type Stars,” 2006, Ap.J., 650, 1096

Owocki & Cohen, “The Effects of Porosity on X-ray Emission Line Profiles From Hot-Star Winds,” 2006, Ap.J., 648, 565

Cohen, Leutenegger, Grizzard (’06), Reed (’05), Kramer (’03), & Owocki, “Wind Signatures in the X-ray Emission Line Profiles of the Late O Supergiant ζ Orionis,” 2006, MNRAS, 368, 1905

Gagne, Oksala (’04), Cohen, Tonnesen (’03), ud-Doula, Owocki, Townsend, & MacFarlane, “Chandra HETGS Multi-phase Spectroscopy of the Young Magnetic O Star θ1 Ori C,” 2005, Ap.J., 628, 986

Kramer (’03), Cohen, & Owocki, “X-ray Emission Line Profile Modeling of O Stars: Fitting a Spherically-Symmetric Analytic Wind-Shock Model to the Chandra Spectrum of ζ Puppis,” 2003, Ap.J., 592, 532

Cohen, de Messieres (’04), MacFarlane, Miller, Cassinelli, Owocki, & Liedahl, “Chandra Spectroscopy of τ Scorpii: A Narrow Lines Spectrum from a Hot Star,” 2003, Ap.J., 586, 495

Owocki & Cohen, “X-ray Line Profiles from Parameterized Emission Within an Accelerating Stellar Wind,” 2001, Ap. J., 559, 1108

UNDERGRADUATE HONORS THESES ADVISED Michael Rosenberg (’08), “Spectral and Hydrodynamic Modeling of X-ray Photoionization

Experiments.” Graduated with High Honors, currently in the MIT physics PhD program. Vernon Chaplin (’07), “High Time Resolution Spectroscopic Measurements of Electron

Temperature in the SSX Plasma.” Apker award finalist; after graduation with High Honors, a year of work in Vietnam; started PhD physics program at Caltech in 2008.

Nathan Shupe (’05), “Modeling Studies of Photoionization Experiments Driven by Z-pinch X-rays.” Graduated with Honors; three years of employment at Lockheed-Martin; started masters program in aeronautical engineering at Univ. Colorado in 2008.

Genevieve de Messieres (’04), “XMM-Newton X-ray Spectroscopy of the B2 Bright Giant ε Canis Majoris.” Graduated with Honors, now at U. Virginia astronomy PhD program.

Roban Kramer (’03), “Modeling O-Star X-Ray Emission Line Profiles.” Graduated with High Honors, now at Columbia University astronomy PhD program.

Stephanie Tonnesen (’03), “X-Ray Emission Line Profiles from the Magnetically Confined Wind Shock Model.” Graduated with Honors, now at Columbia University astronomy PhD program.

Joanna Brown (’02), “Modelling Density Enhanced Shells in the Circumstellar Envelope of the Carbon-Rich AGB Star IRC+10216.” Graduated with Honors; graduated from astronomy PhD program at Caltech, 2007. Now doing research at Max-Planck Institute, Germany.

LEROY APKER AWARD FINALISTS FOR BEST UNDERGRADUATE RESEARCH IN THE

UNITED STATES Emma Wollman (’09) – currently in Caltech Physics PhD program Vernon Chaplin (’07) – currently in Caltech Physics PhD program

DAVID H. COHEN

PUBLICATIONS WITH UNDERGRADUATES

Refereed Journals

Cohen, Leutenegger, Wollman (’09), Zsargo, Hillier, Townsend, & Owocki, “A Mass-Loss Rate Determination for ζ Puppis from the Quantitative Analysis of X-ray Emission Line Profiles,” MNRAS, submitted

Chaplin (’08), Brown, Cohen, Gray, & Cothran, “Spectroscopic Measurements of Temperature and Plasma Impurity Concentration During Magnetic Reconnection at the Swarthmore Spheromak Experiment,” 2009, Physics of Plasmas, in press

Cohen, Kuhn (’07), Gagne, Jensen, & Miller, “Chandra Spectroscopy of the Hot Star β Crucis and the Discovery of a Pre-Main-Sequence Companion,” 2008, MNRAS, 386, 1855

Cohen, Leutenegger, Grizzard (’06), Reed (’05), Kramer (’03), & Owocki, “Wind Signatures in the X-ray Emission Line Profiles of the Late O Supergiant ζ Orionis,” 2006, MNRAS, 368, 1905

Gagne, Oksala (’04), Cohen, Tonnesen (’03), ud-Doula, Owocki, Townsend, & MacFarlane, “Chandra HETGS Multi-phase Spectroscopy of the Young Magnetic O Star θ1 Ori C,” 2005, Ap.J., 628, 986

Cohen, MacFarlane, Jaanimagi, Landen, Haynes, Conners (’03), Penrose (’04), & Shupe (’05) “Tracer Spectroscopy Diagnostics of Doped Ablators in Inertial Confinement Fusion Experiments on OMEGA,” 2004, Physics of Plasmas, 11, 2702

Kramer (’03), Cohen, & Owocki “X-ray Emission Line Profile Modeling of O stars: Fitting a Spherically-Symmetric Analytic Wind-Shock Model to the Chandra Spectrum of ζ Puppis,” 2003, Ap.J., 592, 532

Cohen, de Messieres (’03), MacFarlane, Miller, Cassinelli, Owocki, & Liedahl, “Chandra Spectroscopy of τ Scorpii: A Narrow Lined Spectrum from a Hot Star,” 2003, Ap.J., 586, 495

Kramer (’03), Tonnesen (’03), Cohen, Owocki, ud-Doula, & MacFarlane, “X-ray Line Profile Diagnostics of Shock Heated Stellar Winds,” 2003, Rev. Sci. Inst., 74, 1966

Numerous conference presentations have been given by Cohen’s undergraduate students,

including the recent poster presentation at the 16th International Conference on Atomic Processes in Plasmas, March 2009, by Erin Martell (’09) and Emma Wollman (’09), which was awarded first prize for the best student – graduate as well as undergraduate – poster at the meeting.

_____________________ Futher information available on the web: including brief summaries and links to electronic copies, at http://astro.swarthmore.edu/~cohen/papers.html. Presentations are available at http://astro.swarthmore.edu/~cohen/presentations.html. The theses written by honors students, along with additional information about the student researchers that have worked with David Cohen over the past nine years, are available at http://astro.swarthmore.edu/~cohen/students.html.

Jamie Holder

Address:

Department of Physics and Astronomy,University of Delaware, Newark DE 19711.Phone:(302)831 2545 FAX:(302)831 1637 email:[email protected]

Education:

University of Leeds, UK Physics with Astrophysics B.Sc.(Hons) 1992

University of Durham, UK Gamma Ray Cherenkov Ph.D. 1997Telescope Image Analysis

Postdoctoral Research Positions:

University of Leeds Gamma-ray Astronomy January 2001 toUK VERITAS Collaboration July 2006

Universite Paris-Sud, LAL Gamma-ray Astronomy January 1999 toFrance CELESTE Collaboration December 2000

University of Tokyo, ICRR Gamma-ray Astronomy June 1997 toJapan CANGAROO Collaboration December 1998

Academic Positions:

University of Delaware Assistant Professor from September 2006USA Experimental Particle Astrophysics

Publications Most Closely Related to the Project:

1. Acciari, V. A., et al. (VERITAS Collaboration) “A Connection Between Star Formation

Activity and Cosmic Rays in the Starburst Galaxy M82”, Nature, 462, 770, (2009)2. Acciari, V. A., et al. (VERITAS Collaboration) “Evidence for Long-Term Gamma-Ray

and X-Ray Variability from the Unidentified TeV Source HESS J0632+057”, Ap. J.,698, L94, (2009)3. Holder, J., et al. (VERITAS Collaboration) “Status of the VERITAS Observatory”, AIPConf. Proc., 1085, 657 (2008)4. Smith, A., Kaaret, P., Holder, J., Falcone, A., Maier, G., Pandel, D. & Stroh, M. “Long-Term

X-Ray Monitoring of the TeV Binary LS I +61 303 With the Rossi X-Ray Timing

Explorer”, Ap. J., 693, 1621, (2009)5. Acciari, V. A., et al. (VERITAS Collaboration) “VERITAS Discovery of > 200 GeVGamma-Ray Emission from the Intermediate-Frequency-Peaked BL Lacertae Object

W Comae”, Ap. J., 684, L73, (2008)

Other Significant Publications:

6. LeBohec, S.; Holder, J., “Optical Intensity Interferometry with Atmospheric Cerenkov

Telescope Arrays”, Ap. J., 649, 399, (2006)7. Acciari, V. A., et al. (VERITAS Collaboration) “VERITAS Observations of the Gamma-

Ray Binary LS I +61 303”, Ap. J., 679, 1427, (2008)8. Acciari, V. A., et al. (VERITAS Collaboration) “Observation of Gamma-Ray Emission

from the Galaxy M87 above 250 GeV with VERITAS”, Ap. J., 679, 397, (2008)9. Holder, J., et al. (VERITAS Collaboration) “The first VERITAS telescope”, Astropart.Phys., 25, 391 (2006)

10. Holder, J., et al. (VERITAS Collaboration), “Detection of TeV Gamma Rays from the

BL Lacertae Object 1ES 1959+650 with the Whipple 10 Meter Telescope”, Ap. J., 583,L9, (2003)

Synergistic Activities:

(i) VERITAS positions: Deputy Collaboration Spokesperson, Co-chair Galactic Astrophysics Sci-ence Working Group, Head of the Level Two Trigger sub-project.(ii) Member of the Fermi Users Group (http://fermi.gsfc.nasa.gov/ssc/resources/fug/)(iii) Organised a 3 day VERITAS Collaboration meeting with 50 attendees at the University ofDelaware in June 2007.(iv) Refereed numerous papers for “The Astrophysical Journal” and “Astroparticle Physics”.(v) Departmental committees: Space Committee, Undergraduate Recruitment, Graduate Admis-sions and Recruitment.

Collaborators:

The VERITAS Collaboration - Senior Personnel:Wystan Benbow (SAO), Stella Bradbury (U. Leeds), Guy Blaylock (U. Mass), Jim Buckley (Wash U.St. Louis), Yosaf Butt (SAO), Karen Byrun(ANL), Larry Ciupik (Adler), Wei Cui (Purdue), Char-lie Duke (Grinell), John Finley (Purdue), Lucy Fortson (Adler), Ken Gibbs (SAO), David Hanna(McGill), Liz Hayes (GSFC), Jamie Holder (U. Delaware), Dierdre Horan (ANL), Mary Kertz-man (Depauw), Henrik Krawczynski (Wash U. St. Louis), Phil Karaat (U. of Iowa), Frank Kren-nrich (Iowa State), Mark Lang (NUI), S. Lebohec (Utah), Pat Moriarty (GMIT), Reshmi Mukher-jee(Barnard), Martin Pohl (Iowa State), John Quinn (UC Dublin), Rene A. Ong (UCLA), KenRagan (McGill), Joachim Rose (U. Leeds), Simon Swordy (Chicago), Vladimir Vassiliev (UCLA),Bob Wagner (ANL), Scott Wakely (U. Chicago), Trevor C. Weekes (SAO), David Williams (UCSC).

Graduate Advisors and Postdoctoral Sponsors

University of Leeds, UK: Rose, H.J., Hillas, A.M.Universite Paris-Sud, LAL, France: Eschtruth, P.University of Tokyo, ICRR, Japan: Kifune, T.University of Durham, UK: Orford, K., Osborne, J.

Thesis Advisor and Postgraduate-Scholar Sponsor

Universtity of Delaware, USA: Dana Boltuch (Graduate student)Universtity of Delaware, USA: Dr. Ester Aliu (Post-doc)Universtity of Delaware, USA: Dr. Matthieu Vivier (Post-doc)

1 Budget Justification

To accomplish the ambitious and multi-faceted research goals outlined in this proposal, this projectwill leverage the broad and extensive research experience of the PI and team of co-I’s and collab-orators toward guidance and training of a group younger members at the undergraduate, Ph.D.student, and post-doctoral level. Salary, computer, and travel expenses for these junior membersforms the bulk of the proposed budget. Specifically, we request:

• Full-time, 3-year support for named post-doctoral researcher Ross Parkin, who is currentlycompleting his Ph.D. from Leeds University on modelling X-ray emission from colliding windbinary systems.

• Full-time, 3-year support a new graduate student researcher, who will initiate Ph.D. thesisresearch in one of the subtopics of the project. This would maintain continuity with PIOwocki’s current group of (3) Ph.D. students, who are fully supported by other projects andfellowships, and expected to complete their theses within the first half of the proposed project.Such visibly successful progress of existing students provides a key advantage in attractingand providing the initial training for new students to work in the high-energy processes centralto this project.

• Summer reseach by an undergraduate student from either UDel or nearby Swarthmore Col-lege, where co-I (and former UDel post-doc) D. Cohen is a faculty member. This will build onthe success both Owocki and Cohen have had in mentoring undergraduate research projects.

• Salary support for a one-month summer visit each year to UDel by former UDel student andpost-doc, and current project co-I, A. ud-Doula, who is now a faculty member at MorrisvilleState College. In light of his heavy teaching demands during the academic year, this will en-able active continuation of magnetic wind modelling begun during student and post-doctoralcollaborations with PI Owocki, with now more direct focus on the X-ray emission propertiescentral to this project.

• One month summer salary support for PI Owocki, in partial compensation for his year-roundefforts to lead, guide, and coordinate the overall project.

• In addition to travel support for the post-doc and/or students to present results at scientificconferences, we also request modest travel support for team members to attend regular teamone- or two-day meetings to discuss and coordinate the various science efforts. Such regularmeetings have been a key to the success of our ongoing collaborations on massive stars andtheir X-ray properties.

• $5K funds (with waived overhead) toward purchase of a workstation for post-doc Parkin,to facilitate local analysis of simulations carried out on various local and remote clustersand supercomputers, including time obtained through separate but affiliated applications atNASA computing centers.

The remaining budget items include nominal allotments for materials and supplies, plus thefederally negotiated UDel rates for overhead and benefits.

spowocki

Cross-Out

spowocki

Cross-Out

CURRENT AND PENDING SUPPORT Dr. Stanley P. Owocki

A. Current Support (1) a. Supporting Agency: NASA NNG05GC36G b. Title: Magnetically-Controlled Circumstellar Environments

of Hot-Stars: A Multi-Wavelength Confrontation between Observations and Models

c. Award Amount: $737,345 d. Period: 01/15/2005 – 01/14/2011 (no cost extension) e. Percent of Effort: no salary support f. Location: University of Delaware, Newark, DE (2) a. Supporting Agency: NASA NNX07AO21H (NASA GSRP Fellowship) b. Title: Determining the Properties of the Eta-Carinae System

via Hydrodynamical Models of Space-Based Observations

c. Award Amount: $90,000 d. Period: 07/16/2007 – 07/15/2010 e. Percent of Effort: no salary support f. Location: University of Delaware, Newark, DE (3) a. Supporting Agency: NASA NNX08AT36H (NASA GSRP Fellowship) b. Title: Using Hydrodynamical Simulations to Probe Colliding

Wind Binaries c. Award Amount: $60,000 d. Period: 07/01/2008 – 06/30/2010 e. Percent of Effort: No Salary f. Location: University of Delaware, Newark, DE

B. Pending Support

(1) a. Supporting Agency: NASA – current proposal b. Title: Dynamical Models for High Energy Emission from

Massive Stars c. Award Amount: $540,713 d. Period: Submitted for 3 Years – 01/01/2011 – 12/31/2013 e. Percent of Effort: 1 summer month

f. Location: University of Delaware, Newark, DE

Current and Pending Support: co-I David Cohen UCurrent Support A New Observatory for Undergraduate Training and Faculty Research at Swarthmore College PI: Eric L. Jensen, Swarthmore College (David Cohen, Co-PI) Agency/Program: National Science Foundation, Program for Research and Education with Small Telescopes (PREST) Performance Period: 8/1/07 – 7/31/10 Total budget: $310,109 Person-months per year: Jensen – Year 1 (0.0); Year 2: (0.5); Year 3: (0.5); Cohen – Year 1 (0.0); Year 2: (0.5); Year 3: (0.5) Experiments and Modeling of Photoionized Plasmas at Z PI: R.C. Mancini, University of Nevada, Reno (David Cohen, Co-PI) Agency/Program: Department of Energy, Stewardship Science Academic Alliances Program Performance Period: 8/20/09 – 8/19/12 Total budget: $650,000 (Swarthmore: $41,473) Person-months per year: Cohen – Year 1 (0.95); Year 2: (0.95); Year 3 (0.95 months) Multiwavelength Study of Early-Type Stars Observed with Chandra HETGS PI: Janos Zsargo, University of Pittsburgh (David Cohen, Co-PI) Agency/Program: Smithsonian Astrophysical Observatory, Chandra Guest Observer Program Performance Period: 1/1/10 – 2/29/12 Total budget: $115,000 (Swarthmore: $15,894) Person-months per year: Cohen - 1.0 X-Rays from Magnetically Confined Hot Plasma in tau Sco PI: Richard Ignace, East Tennessee State University (David Cohen, Co-PI) Agency/Program: National Aeronautics and Space Administration (Suzaku Guest Observer Program) Performance Period: 9/1/10 – 8/31/11 Total budget: $30,530 (Swarthmore: $2,380) Person-months per year: Cohen - 0.0 UPending Support O Star Mass-Loss Rates and Shock Physics from X-ray Line Profiles in Archival XMM RGS Data PI: David Cohen, Swarthmore College Agency/Program: National Aeronautics and Space Administration Performance Period: 1/1/11 – 12/31/12 Total budget: $219,477 Person-months per year: Cohen – Year 1: 2.0 mo, Year 2: 5.5 mo

Dynamical Models for High Energy Emission from Massive Stars (this proposal) PI: Stan Owocki, University of Delaware Agency/Program: National Aeronautics and Space Administration Performance Period: 1/1/11 – 12/31/13 Total budget: $540,713 Person-months per year: Cohen – 0.0 mo.

CURRENT AND PENDING SUPPORT Dr. Jamie Holder

A. Current Support (1) a. Supporting Agency: NASA NNX09AR91G

b. Title: Exploring the GeV-TeV Connection in LS 1 +61 303 with Fermi and VERITAS

c. Award Amount: $70,000 d. Period: 08/14/2009 – 08/15/2010 e. Percent of Effort: 0.5 month summer salary


B. Pending Support

(1) a. Supporting Agency: University of Utah through NSF b. Title: MRI-R2 Consortium: Development of Improved

Instrumentation for the VERITAS Gamma-Ray Observatory

c. Award Amount: $350,906 d. Period: Submitted for 3 Years – 03/15/2010 – 03/14/2013 e. Percent of Effort: no salary

f. Location: University of Delaware, Newark, DE (2) a. Supporting Agency: SAO

b. Title: Development of Improved Instrumentation for the VERITAS Gamma-Ray Observatory


f. Location: University of Delaware, Newark, DE (3) a. Supporting Agency: DOE

b. Title: Studying Cosmic Ray Sources with VERITAS and Developing New Tools for High Energy Gamma-Ray Astronomy

c. Award Amount: $608,711 d. Period: Submitted for 3 Years – -2/01/2010 – 01/31/2013 e. Percent of Effort: 1 summer month


CURRENT AND PENDING SUPPORT Dr. Jamie Holder

(4) a. Supporting Agency: NASA – current proposal

b. Title: Dynamical Models for High Energy Emission from Massive Stars



Cover Page for Proposal NASA Proposal Number Submitted …owocki/xfr/Owocki-ATP-May10-N... ·...

Documents

Transcript of Cover Page for Proposal NASA Proposal Number Submitted …owocki/xfr/Owocki-ATP-May10-N... ·...