NAIC-AUSAC Meeting April 19 & 20, 2010

Chris Salter (NAIC – Arecibo)

GALFA & GALFACTSGALFA & GALFACTS

GALFA-HI and GALFACTS (Courtesy: Steven Gibson)

NAIC-AUSAC Meeting April 19 & 20, 2010

GALFA Sub-ConsortiaGALFA Sub-Consortia

• H I Line (GALFA-H I)

• Continuum (GALFA-CON = GALFACTS)

• Radio Recombination Lines (GALFA-RRL)

• Each GALFA sub-consortium has its own membership and internal organization.

• All GALFA data will be made public through the National Virtual Observatory.

NAIC-AUSAC Meeting April 19 & 20, 2010

RRL Galactic-Plane SurveyRRL Galactic-Plane Survey

• Galactic Structure

• Chemical Abundances

• Warm Diffuse ISM

• HII Regions

• Survey for |b| < 5o

• Integration time of 300-600s

• Commensal with PALFA & ZoA projects

• Share a “Mock spectrometer” database with ZoA (Δv≈4 kms-1)

• Record H163α−H174α, plus He & C α-lines and H β-lines

• Co-add transitions to increase signal-to-noise

• “Leap-Frog” Pointing to provide ON/OFFs

(Terzian & Lewis)

NAIC-AUSAC Meeting April 19 & 20, 2010

GALFACTS (GALFA Continuum Transit Survey)GALFACTS (GALFA Continuum Transit Survey) • Full-Stokes, all-Arecibo-sky, continuum

survey.

• Employs meridian NODding scans with subsequent “multi-beam” basket-weaving to optimize zero-levels.

• Bandwidth = 300 MHz → Faraday tomography, Ip(x, y, RM).

• Use “winking cal” for best possible calibration.

• Use of an original multi-beam CLEAN.

• To date, two extensive regions observed; (a) 1h<RA<7h; 20°<δ<38° in Nov-Dev 2009, and, (b) 4h<RA<10h; −1°<δ<17°)i in Dec 2009 and Jan 2010.

Stokes I Dirty Image

Multi-beam Clean Image (HPBW=3.5')

NVSS Comparison(HPBW=0.7')

NAIC-AUSAC Meeting April 19 & 20, 2010

Mapping Technique: ZA Nodding (+ AZ Wagging)Mapping Technique: ZA Nodding (+ AZ Wagging)

ALFA beams

Tracks after several passes

These are “woven” together to optimize zerolevels.

• P.I.: Russ Taylor

• Web Page: www.ucalgary.ca/ras/GALFACTS

• 14400 channels over 300-MHz bandwidth with “Mock spectrometer”

• Brightness sensitivity: rms~100 μJy/bm

• Meridian scanning speed ~1.5° per sec

• CIMA “Smart Basket-weaving” used

NAIC-AUSAC Meeting April 19 & 20, 2010

GALFACTS (continued)GALFACTS (continued)• Catalog of Poln. Percentage, Position

Angle & RM for 50,000 sources → Galactic Magnetic Field Studies.

• Thermal-nonthermal separation of low-b Galactic continuum emission.

• Provide thermal brightnesses for use by GALFA-RRL.

• Studies of discrete Galactic radio sources (e.g. SNRs & HII regions).

• Studies of high-b Galactic Loops.

• Foreground removal for EoR and Planck full-Stokes CMB studies.

• GALFA-HI TOG2 commensal project.

• First GALFACTS look at the Galactic Center quadrant via commensal observations with I-GALFA.

Beam 5 missing from Stokes-I.Beams 5 & 6 missing from Q & U.

Stokes I

Stokes Q

Stokes U

WHY GALFA-HI?WHY GALFA-HI?With single-dish brightness temperature sensitivity and high spectral and angular resolution, it covers new parameter space:

NAIC-AUSAC Meeting April 19 & 20, 2010

GALFA-HI Pointing Record as of 2008 March 14

GALSPECT has 8192 channels over 7.14 MHz → 0.18 km/s/channel, and ± 750 km/s total coverage

GALFA-H I Observations

GALFA-HI Pointing Record as of 2009 February 26

GALFA-HI Pointing Record as of 2010 April 4

NAIC-AUSAC Meeting April 19 & 20, 2010

I-GALFAI-GALFA – The Inner Galaxy ALFA low-– The Inner Galaxy ALFA low-bb HI Survey HI Survey

• I-GALFA covers 35°≤ l ≤85°, |b| ≤10°.

• Observations were completed in September 2009.

• HPBW=3.35', Trms

= 0.25 K, Δv

chan = 0.18 km/s, |v

lsr| < 750 km/s.

• (Triple) Commensal with ZOA & GALFACTS2.

•Prominent is the HI/continuum supershell GS 041+01+27, probably lying in the Sagittarius spiral arm.

(top) I-GALFA HI image – vlsr

= +27 km/s; (bottom) GALFACTS2 L-band continuum image

Disc-Halo Interface

NAIC-AUSAC Meeting April 19 & 20, 2010

• TOGS/TOGS2 is commensal with GALFACTS, ALFALFA & AGES, mapping the whole Arecibo sky in HI at no overhead in observing time.

• Used to study, (a) Galactic structure, (b) correlation of HVC HI and dust contents, (c) HI clouds surrounding M33 attributed to M33–M31 tidal interactions, (d) HI content of Local Group dwarf galaxies, and (e) HI content of globular clusters.

GALFA-TOGS/TOGS2 Wide-Area HI SurveyGALFA-TOGS/TOGS2 Wide-Area HI Survey

TOGS = “Turn On GALFA Spectrometer!” HI for -5 ≤ vlsr

≤ 0 km/ s

(Image includes I-GALFA data)

NAIC-AUSAC Meeting April 19 & 20, 2010

The Three Little Pigs (and a Friend)The Three Little Pigs (and a Friend)(PI: Josh Goldston Peek)

• Tiny clouds found at b ≈ 85°; Δθ ≈ 1'.

• VLA follow-up shows condensed cores , optically-thick, with TB ≈ 10K.

• Arecibo measures Magnetic Field strength ~14 μG → 200 – 800 times the magnetic pressure of the WIM.

• Upper limits on OH emission from Arecibo.

NAIC-AUSAC Meeting April 19 & 20, 2010

Pigs by the Drove!Pigs by the Drove!Ayesha Begum & Snezana Stanimirovic

• About 100 compact, cold clouds, isolated from Galactic emission found in a limited area of the TOGS/TOGS2 survey.

• Median angular size ~5', Tb ~ 0.7 K, FWHM ~ 4.2 km/s, and N

HI ~ 5 × 1018 cm-2.

• Clouds deviate from Galactic rotation by 10 – 40 km/s, and evidence for multiphase medium and velocity gradients.

• If D ≤ 100 pc, then thermal pressure is order of magnitude > ISM. and size ≤ 30,000 AU suggesting short lifetimes. Could be 'spray' of transient, small, HI clouds resulting from ISM turbulence effects.• If D = 1 – 3 kpc, then they would represent 'pockets' of cold HI immersed in warm/hot halo gas. Explaining their survival is then a challenge.

HI Outflows from RS-CVn variables (eclipsing binaries with magnetically active chromospheres).

-100 to -70 km/s -40 to -25 km/s

NAIC-AUSAC Meeting April 19 & 20, 2010

GALFA Summary• 3 Sub-Consortia; GALFA-H I, -CON (& -RRL)

• Small GALFA-H I projects completed

• TOGS1&2 in progress; data analysis on-going

• I-GALFA completed; GALFACTS ~20% complete

• PALFA acquiring RRL/ZOA data

• All final GALFA datasets will be available via NVO

• GALFA website: www.naic.edu/alfa/galfa

NAIC-AUSAC Meeting April 19 & 20, 2010

Muchas Muchas GraciasGracias

NAIC-AUSAC Meeting April 19 & 20, 2010

GALFACTS (GALFA Continuum Transit Survey)GALFACTS (GALFA Continuum Transit Survey) • GALFACTS is a full-Stokes, all-Arecibo-sky, continuum survey.

• It uses the Mock spectrometer, and an original multi-beam CLEAN.

• The GALFACTS survey began November 2008, and is about 12% complete.

• Studies of a) Galactic magnetic field via both point-source and foreground polarization, b) thermal/nonthermal separation of Galactic foreground, & c) SNRs, HII regions and the Galactic loops.

• Bandwidth = 300 MHz → Faraday tomography, Ip(x, y, RM).

NAIC-AUSAC Meeting April 19 & 20, 2010

GALFA - H I Projects

56% Mar 1716% Mar 1778% Mar 17

start ASAP

start May 3

Marrying NVSS and GALFA-HI will provide >1000 positions with reliable temperatures. This freezing cold cloud lies only 20 pc from the Sun—within the local bubble!

NAIC-AUSAC Meeting April 19 & 20, 2010

CGPSVGPS

SGPS

I-GALFA Plane H I Survey

10 x IGPS sensitivity, 4 x velocity resolution

I-GALFA Survey: 2008-9

NAIC-AUSAC Meeting April 19 & 20, 2010

GALFA H I Projects

a2186/2144/2390

a2048/2059a2010/2059a2130/2124

a2056/2051a2060

a2055

a2034

a1943

a2004

a2174/2294

a2221

ALFALFA/TOGS1 AGES/TOGS1 GALFACTS/TOGS2

I-GALFA/ZOA/ GALFACTS2 DISK-

HALOMBW/ZOA

PERSEUS

TAURUS

HALOCLOUDS

WINGS

a2220

a2222a2187

a2050

a2011 a2011a2172

a2172

a2147a2032

TIP MAGSTREAM GEM

OB1

TRUE FIL

SHELL

HIGH-LAT CLOUDS

HIGH-LATTURBULENCE

WATER FALL

OUTER HALO

PRECURSOR

COLDCLOUD

(Trms ~ 0.25 K)

(Trms ~ 0.15 K) (Trms ~ 0.04 K) (Trms ~ 0.35 K)