1st page of proposal with 2 pictures and institution list 1.
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Transcript of 1st page of proposal with 2 pictures and institution list 1.
1st page of proposal
with 2 pictures and institution list
1
Milagro@SAGENAP
OUTLINE
I. Astrophysics from MilagroBrenda Dingus, University of Wisconsin--Madison
II. The Milagro DetectorGus Sinnis, Los Alamos National Laboratory
III. Results from MilagroDon Coyne, University of California Santa Cruz
IV. Completion of Milagro with OutriggersTony Shoup, University of California Irvine
V. Budget & Funding HistoryJordan Goodman, University of Maryland
BOTTOM LINE Large field of view TeV observatory has unique scientific
abilities that complement VERITAS / GLAST. Milagro has been built to budget and is now taking data. Milagrito & preliminary Milagro data indicate the
scientific goals are within reach. A significant improvement in the sensitivity can be
accomplished by completing the planned construction. Need support for Milagro operations, data analysis, and
last 10% of construction.
2
Astrophysics from MilagroAstrophysics from Milagro 3
Radio Optical X-ray GeV TeV
E2 dN/dEorν Fν
TeV Astrophysics
Lower Energy Bump is
Synchrotron Emission from Relativistic Electrons
Higher Energy Bump is ?
Electron Inverse Compton Scattering
AND/OR Proton Induced Cascades
Peak of Both Bumps is sensitive to Eparticle, B, nphoton, ngas
Peak of Both Bumps exhibits greatest VARIABILITY
Typical Multiwavelength Spectrum
from High Energy -ray source
Astrophysics from MilagroAstrophysics from Milagro 4
Astrophysical Sources
TeV All Sky Map
Astrophysics from MilagroAstrophysics from Milagro 5
Why so Few Observed TeV Sources?
Perhaps Fewer TeV Accelerators, but X-ray emission from supernova remnants and
active galactic nuclei => TeV electrons Sources of ultrahigh energy cosmic rays likely to emit
TeV -rays
TeV -rays are Attenuated (TeV) + (eV)
--> e - + e +
Attenuation can be internal to the source or in transitTransit attenuation depends on model of Galaxy FormationObservation of ~200 GeV -rays implies z<0.3
Better TeV Observatories are Required Improved Flux Sensitivity to Detect Weaker Sources
VERITAS, HESS, MAGIC, CANGAROO
Lower Energy Threshold to Detect Distant SourcesSTACEE, CELESTE, Solar 2
Large Field of View, High Duty Factor to Identify New and Flaring Sources
MILAGRO, Tibet EA, ARGO
Primack et al, 1999
Astrophysics from MilagroAstrophysics from Milagro 6
TeV Observatories
GeV Observatories
EGRET 0.6 sr 30% live time
GLAST 2.4 sr 90% live time
TeV Observatories
Atmospheric 0.003 sr 5-10% live timeCherenkov => ~ dozen sources / yearTelescopes with plotted sensitivity
Milagro 2 sr > 90% live time
Astrophysics from MilagroAstrophysics from Milagro 7
Variability of Active Galactic Nuclei (AGN)
GeV Observations
66-93 AGN detected (Hartman et al, 1999) >70% are variable (Mukherjee et al, 1999) Some variability is correlated with other wavelengths but some is NOT
TeV Observations Mrk 421 & Mrk 501
Detected by Many Observers
Both Variable
Mrk 421 Rapid Flares
Mrk 501 Long High State Other AGN
Only detected once
Only detected by 1 Observer
1ES2344+514
PKS2155-304
1ES1959+650
3C66AWhipple Mrk501 light curve
Quinn et al 1999
X-ray
> 100 MeV
Astrophysics from MilagroAstrophysics from Milagro 8
Gamma Ray Bursts (GRBs)
Rapid Variability, Unknown Direction, ~ 1 / day / 4 sr
=> Large Field of View, High Duty Factor ESSENTIAL
Slew time for PointedTeV Observatories
Astrophysics from MilagroAstrophysics from Milagro 9
date redshift total energyfor isotropic emission
970228 0.695 5 x 10 51 ergs970508 0.835 8 x 10 51 ergs970828 0.958971214 3.412 3 x 10 53 ergs980425 0.0085 7 x 10 47 ergs980613 1.096980703 0.967 1 x 10 53 ergs990123 1.600 3 x 10 54 ergs990510 1.619 3 x 10 53 ergs990712 0.43991208 0.706 1 x 10 53 ergs991216 1.02000301C 2.0335 2 x 10 51 ergs
Are GRBs near enough?
Distance has been measured to the host galaxies or optical afterglows of ~ dozen GRBs
% of GRBs near enough for TeV observations is uncertainDistance distributions inferred from the BATSE-measured
fluence distribution varies from <0.1% (Schmidt,1999) to ~10% (Dermer, 2000) of GRBs being within z < 0.3.
Different distance distributions are expected from hypernovae (death of massive stars) than from neutron star - neutron star coalescences
More than one population of GRB sources may exist with different distance distributions
Astrophysics from MilagroAstrophysics from Milagro 10
TeV -rays from GRBs
GeV Observations => Relativistically expanding fireball with Bulk Lorentz Factors of 100-1000
Average EGRET spectrum from brightest bursts => E-1.95±0.25 differential power law extending to 10 GeV
Evidence of TeV emission from GRB970417a from Milagrito (Atkins et al. 2000 ApJ Lett in press)
GRB Spectral evolution from model of Dermer, 1999
Astrophysics from MilagroAstrophysics from Milagro 11
Extended SourcesAtmospheric Cherenkov Telescopes are less effective at rejecting
cosmic-ray background for non-point sourcesLong integration time of Milagro can improve sensitivity
Supernova RemnantsSizes can extend to a few degreesHighest energy observations identify proton produced -rays
Galactic Plane GeV flux measurements are higher than model predictionExcess can be explained by Inverse Compton emission which
may be observable in TeV -raysMilagro observes 106 cosmic-rays/day within 1o of plane and Air
Cherenkov Telescope u.l. are ~10-3 of the cosmic ray flux
Non-Transient Sources
IC
p+p
Brem.
Poh l & Esposito, 1998
Astrophysics from MilagroAstrophysics from Milagro 12
The Unknown
60% of EGRET sources are unidentifiedMany are Galactic Some have hard spectraSome are variable (one exceeded the Crab flux once)TeV detections would measure more precise position
New TeV sources may existMilagrito performed 1st all sky TeV survey
No point sources with continuous flux > 5 x Crab flux exist in Northern Hemisphere (A. Smith et al. 1999)
Possible new sources include
Evaporation of Primordial Black Holes
Galactic Black Holes with Relativistic Jets
X-ray Binaries
TeV- selected Active Galactic Nuclei
??????
Astrophysics from MilagroAstrophysics from Milagro 13
Astrophysics from Milagro
TeV -ray observations add to our understanding of Nature’s Highest Energy Particle Accelerators
GeV-TeV -ray astrophysics is an active and growing field with new observations and observatories
Milagro is an All-Sky TeV monitor of the northern hemisphere with unique, but complementary, capabilities to the many current and planned TeV pointed observatories