Title: GeV-TeV Gamma-ray Astronomy
1GeV-TeV Gamma-ray Astronomy
International Workshop on Extremely High Energy
Cosmic Rays, March 22-23, 2001, Kashiwa
- Masaki Mori
- ICRR, Univ. Tokyo
http//icrhp9.icrr.u-tokyo.ac.jp
2Gamma-ray astronomy short history
- Prediction of nuclear gamma-rays Hayakawa 1952
Morrison 1958 - Ground-based Cherenkov Jelly (1953), Chudakov
(1960-) - Prediction of emission from the Crab nebula
Cocconi 1959 nuclear Gould 1965 inverse
Compton - Satellites OSO-3 (1967-68), SAS-2 (1972-73),
COS-B (1975-82) - Compton Gamma Ray Observatory EGRET/COMPTEL/OSSE/B
ATSE (1991-2000) - Imaging Cherenkov Whipple, CANGAROO, HEGRA
(1980s-1990s)
3Gamma-ray emission mechanisms
- Gamma-rays are produced in inherently non-thermal
processes!
p matter
e? B
e? matter
e? h?
4CGRO/EGRET
- Apr 1991 Jun 2000
- 30 MeV 30 GeV
- ?675.85?(100 MeV/E)0.534
5EGRET Allsky Map
6EGRET observed intensity
Galactic longitude
Galactic latitude
7EGRET diffuse emission model
8EGRET sources observed - model
9Diffuse gamma-ray spectrum
- Flatter than expected (E -2.75) why?? Flatter
proton/electron spectrum??
Nishimura et al.
EGRET
JACEE
?0
Whipple
Brems
uniform
IC
S. Hunter, Heidelberg WS, 2000
10Third EGRET catalog
R.C. Hartman et al., ApJS, 1999
11EGRET point source summary
R.C. Hartman et al., ApJS, 1999
12Pulsars
Radio Princeton catalog (706 pulsars), 1995
MeV only
(GeV candidates 1046-58, 065614, J02184232)
GeV Thompson, Heidelberg WS, 2000
13Pulsars radio vs gamma-ray
Thompson, Heidelberg WS, 2000
14Gamma-ray pulsar light curves
GLAST proposal
15BL Lacs and EGRET AGNs
RED EGRET 3rd catalog AGNs Green Padovani
Giommi MN 1995
TeV Whipple, HEGRA, CAT, 7TA, Durham
16Gamma-ray blazars
H(igh freq. peaked) BL ? X(-ray selected)
BL L(ow-freq. peaked) BL ? R(adio-selected) BL
Lin et al. ApJ 1999
Mukherjee et al. ApJ 1997
17Multiwavelength spectrum of AGNs
- Double-peaked structure synchrotron inverse
Compton
Kataoka, Ph.D 2000
Mrk 421 (z0.03, XBL)
PKS0528134 (z2.1, FSRQ)
? ?IC ?2?sync
? ?sync
Kubo et al. ApJ 1998
18EGRET unidentified sources
- Low vs High latitude
- Persistent vs Variable
- Geminga-like pulsars?
- SNRs?
- OB associations?
- Gould belt?
I. Grenier, GeV-TeV WS, 1999
19EGRET unIDs and SNRs
RED EGRET 3rd catalog unID Green D.A. Greens
catalog
TeV CANGAROO
TeV HEGRA
GeV Esposito et al. ApJ 461, 1996
20Extragalactic diffuse gamma-rays
- Single power-law E 2.10?0.03 (30 MeV-100 GeV)
- Unresolved point sources (ex. Blazars
etc.)?Upscattered CMB?
E 2.10?0.03
P. Sreekumnar et al., ApJ 1998
21Imaging Cherenkov technique
22Image parameters
?
(Simulation)
D.J. Fegan, J.Phys.G, 1997
23Example of image cut analysis
- Hadron rejection power 100
Whipple
CANGAROO (Vela)
M. Punch et al., Nature, 1992
T. Yoshikoshi et al., ApJ, 1997
24TeV catalog 2000
Classification Object Group Remark
Grade A (gt5s,multiple) Crab PSR1706-44 Mrk 421 Mrk 501 Many CANGAROO, Durham Many Many Plerion Plerion AGN (BL Lac) AGN (BL Lac)
Grade B (gt5s) SN1006 Vela RXJ1713.7-3946 PKS2155-304 1ES1959650 BL Lac CANGAROO CANGAROO CANGAROO Durham Utah7TA Crimea SNR Plerion SNR AGN (BL Lac) AGN (BL Lac) AGN (BL Lac)
Grade C (strong but with somequalifications) Cas A Cen X-3 1ES2344514 3C66A Geminga B1509-58 HEGRA CT Durham Whipple Crimea Crimea CANGAROO SNR X-ray binary AGN (BL Lac) AGN (z0.44) Pulsar Plerion
T.C. Weekes, Heidelberg WS, 2000
25TeV sky 2000
26TeV observations of Plerions
S. Fegan, astro-ph/0102324
27Crab nebula
Aharonian Atoyan, astro-ph/9803091 / Heidelberg
WS, 2000
synchrotron
IC
28Crab pulsar spectrum where is the cutoff?
Musquere, 26th ICRC, 1999
29TeV observations of shell-type SNRs
S. Fegan, astro-ph/0102324
30Supernova remnant SN1006
T. Naito
31SNR SN1006 - interpretation
Naito et al. Astron. Nach. 320, 1999
- SynchIC
- Only IC?
- No pro-tons?
32TeV observations of AGNs
(Detection of 1ES1426428 (z0.13) is claimed by
Whipple but not published)
Krennrich, astro-ph/0101120
33AGN Mrk 421 variability
- Time scale lt a few hours
- Correlation with X-ray flux
Takahashi et al. ApJ 542, 2000
Gaidos et al., Nature, 383, 1996
34AGN Mrk 421 spectrum
z0.031
- Synchrotron inverse Comptonmodel workswell?
e? origin - Proton modelstill possible
Takahashi et al. ApJ 542, 2000
synchrotron
inverse Compton
One-zone SSC model d14, B0.14G
35AGN TeV gamma-ray absorption by IR background
Mean free path for ee- pair production
IR Background
Protheroe et al. astro-ph/0005349
36AGN Mrk 501 spectrum
z0.033
Crisis??
Protheroe et al. astro-ph/0005349
Aharonian et al. AAp 349, 1999
37Next generation projects
- SatellitesMeV INTEGRAL 15keV-10MeV, 2002-
ACT (Advanced Compton Telescope) 300keV-20MeV,
2008?GeV AGILE 30MeV-50GeV, 2003- GLAST
20MeV-300GeV, 2005? - Ground-basedCANGAROO-III 4?10m, Australia,
2000-2004-MAGIC 1?17m, Canary Island, 2001-HESS
4?12m, Namibia, 2002-VERITAS 7?10m, Arizona,
2004-
38Sensitivity of future detectors
39Summary
Gamma-ray observation maps the non-thermal
Universe!
- Plerions (pulsar nebula)Inverse Compton? ?
synchrotron origin? - PulsarsCutoff in pulse component? ? polar
cap/outer gap - SNRsp0 contribution? ? cosmic ray origin
- AGNsGamma-ray source e or p?Intergalactic IR
? cosmology - EGRET unIDs, Neutralinos, GRBs,
QG,Galactic/extragalactic diffuse,, and more?