# Presentation: 810132

## Gamma-Ray Observations of Extragalactic Objects

- Active Galactic Nuclei.
- Cosmic Rays In Extragalactic Systems.
- Not Covered Here:
- Gamma-Ray Bursts (talk by A. Falcone).
- Extragalactic Dark Matter Studies (talk by J. Buckley).

- J. Buckley, P. Coppi, B. Dingus, A. Falcone, S. Feegan, D. Horan, *H. Krawczynski*, F. Krennrich, R. Mukherjee, M. Pohl, V. Vassiliev

## Active Galactic Nuclei

- JetSources

- AGN

**Notes:**
Jet Sources and Accretion Disk itself!
271 -ray sources in 3rd EGRET catalog:
68 extragalactic:
66 blazars, 
1 radio galaxy, and 
1 normal galaxy
2/3 remain unidentified.

## Blazars

- BL Lacs

- Quasars

- VERITAS, HESS, MAGIC &GLAST

**Notes:**
271 -ray sources in 3rd EGRET catalog:
68 extragalactic:
66 blazars, 
1 radio galaxy, and 
1 normal galaxy
2/3 remain unidentified.

## Blazars

- BL Lacs

- Quasars

-  Precision Studies of:  UHECR and/or e+/- Acceleration and  Jet Structure and Formation?

- Spatially Unresolved + Non-Isotropic

- Future IACTs:
-  Pinpoint GLAST Sources.

**Notes:**
 2005ApJ...629...52S
Sokolov, Andrei; Marscher, Alan P.
271 -ray sources in 3rd EGRET catalog:
68 extragalactic:
66 blazars, 
1 radio galaxy, and 
1 normal galaxy
2/3 remain unidentified.

## Blazars

- BL Lacs

- Quasars

**Notes:**
271 -ray sources in 3rd EGRET catalog:
68 extragalactic:
66 blazars, 
1 radio galaxy, and 
1 normal galaxy
2/3 remain unidentified.

## Blazars and the EBL

- Z>0.3: 20 GeV-100 GeV Is Important.

## Pairhalos

## Non-Blazar AGN

- Interpretation:
-  Misaligned Blazars (Bailey et al., 1986, Reimer & Protheroe 2004, Derishev et al. 2005)
-  Jet Emission from pc-Scale Jet Seen Off-Axis
-  Emission from kpc-scale Jet (Kraft et al. 2002, Stawarz et al. 2003)
-  Emission from kpc-Scale Jet

- Detected by EGRET (Sreekumar et al. 1999)

- Detected by HEGRA and HESS (Aharonian et al. 2003, Beilicke et al. 2005 )

**Notes:**
According to Stawarz et al. -- Only nearby radio galaxies like Cen A and M 87 jets are expected to be observed at GeV/TeV energies. --
      VHE emission in M87 is possibly due to the Comptonization of the stellar and circumstellar IR photons of the host galaxy. 

     Predictions: large scale jets of most radio galaxies will not be detected at GeV/TeV energies. 

## Electromagnetism in Strong-Gravity Environment

- Fundamental Physics:
- 	Spacetime and Electromagnetism Close to Event Horizon

- AGN: TeV Emission Cannot Escape

- Quasar Remnants (Boldt et al. 1999, 2000,  Falcone et al.):
-  M > 109 M.
-  ADAF Accretion.

-  UHECRs
-  TeV -Rays From P-Curvature Radiation
-  ADAF  B, P+  0  , TeV+IR e+ e-
-  Source Candidates: Virgo and Fornax Galaxies

## -Ray Studies of Cosmic Rays

- P + N  N* + + X
-   
- + Emission from Primary and Secondary Electrons.
- We Neglect Electronic Component in the Following.

- Cosmic Ray Accelerators:

## Slide 11

## Slide 12

## GLAST vs. VERITASAngular Resolution

- GLAST vs. VERITASAngular Resolution

## GLAST vs. VERITASAngular Resolution

- GLAST vs. VERITASAngular Resolution

## GLAST vs. VERITASAngular Resolution

- 0.1o

- GLAST vs. VERITASAngular Resolution

- CXO/STSI

## GLAST vs. VERITASSensitivity

- >100 GeV Obs. Require Hard Proton Energy Spectrum:
-  Star Burst Galaxies	: B-Field, Gas Density.
-  Galaxy Clusters	: P-Trapping By ICM B-Field.

- GLAST vs. VERITASSensitivity

## -Ray Studies of Cosmic Rays In Other Galaxies

- Flux Estimates: EC from: 	Gas Dens. (Fichtel et al. 1991), 	SN Rate + CR Transport 	(Voelk et al. 1996, Pavlidou & Fields 2001) or 	Radio Emission (Pohl et al. 1996)+ Gas Density + Distance.

- F(>100 MeV) ~ 10-8 cm-2 s-1 For the Strongest Sources

- F300 ~ 1.5%-15% Crab NGC 253 < 1.6% Crab (Aharonian et al., 2005)

- Starburst Galaxies

- CXO/STSI

**Notes:**
Image Widths:
M87: 0.13 degree acrossM31: 2.5
Extragalactic Observations:
Test SNRs and CR acceleration paradigm
CR distributions in regions of high SF
Potential sources of cosmological VHE diffuse backgrounds
CR Re-acceleration at large scales (>10 kpc)
Starburst phenomena & relative influence of central black holes (effect of central radio sources)

## -Ray Studies of Cosmic Rays In Other Galaxies

- Starburst Galaxies

- Science Drivers:
-  CR Acceleration by SNRs;
-  Correlate Flux and Spectrum 	With Galaxy Properties.

- 0.1o

- CXO/STSI

**Notes:**
Image Widths:
M87: 0.13 degree acrossM31: 2.5
Images from three of NASA's Great Observatories were combined to create this spectacular, multiwavelength view of the starburst galaxy M82. Chandra X-ray Images of M82
 Optical light from stars (yellow-green/Hubble Space Telescope) shows the disk of a modest-sized, apparently normal galaxy. Another Hubble observation designed to image 10,000 degree Celsius hydrogen gas (orange) reveals a startlingly different picture of matter blasting out of the galaxy. The Spitzer Space Telescope infrared image (red) shows that cool gas and dust are also being ejected. Chandra's X-ray image (blue) reveals gas that has been heated to millions of degrees by the violent outflow. The eruption can be traced back to the central regions of the galaxy where stars are forming at a furious rate, some 10 times faster than in the Milky Way Galaxy. Many of these newly formed stars are very massive and race through their evolution to explode as supernovas. Vigorous mass loss from these stars before they explode, and the heat generated by the supernovas drive the gas out of the galaxy at millions of miles per hour. It is thought that the expulsion of matter from a galaxy during bursts of star formation is one of the main ways of spreading elements like carbon and oxygen throughout the universe. The burst of star formation in M82 is thought to have been initiated by shock waves generated in a close encounter with a large nearby galaxy, M81, about 100 million years ago. These shock waves triggered the collapse of giant clouds of dust and gas in M82. In another 100 million years or so, most of the gas and dust will have been used to form stars, or blown out of the galaxy, so the starburst will subside. Fast Facts for M82:Credit X-ray: NASA/CXC/JHU/D.Strickland; Optical: NASA/ESA/STScI/AURA/The Hubble Heritage Team; IR: NASA/JPL-Caltech/Univ. of AZ/C. Engelbracht
Scale Image is 7.9 arcmin across
Category Normal Galaxies & Starburst GalaxiesCoordinates (J2000) RA 09h 55m 52.60s | Dec +69° 40' 47.10" 
Constellation Ursa MajorObservation Dates June 18, 2002 
Observation Time 
5 hours
Obs. ID 2933
Orientation 
See Annotated ImageColor Code Energy (X-ray: Blue; Optical: Green & Orange; Infrared: Red)
Instrument ACISAlso Known As Cigar Galaxy
Distance Estimate About 11 - 13 million light years 
Release Date April 24, 2006
More Information on M82: 
More Images of M82 M82 Handout: html | pdf Zoom in on M82 (flash) M82 Animations Powerpoint and PDF Download image for your desktop 
Related Chandra Images:Photo Album: M82 (05 Jun 01)Photo Album: M82 Black Hole (12 Sep 00)Photo Album: M82 (14 Jan 00)
Related Sites:Spitzer Space TelescopeHubble Heritage Project
More Information on Normal Galaxies & Starburst Galaxies :X-ray Astronomy Field Guide: Normal Galaxies & Starburst Galaxies Questions and Answers: Galaxies, Galaxy Clusters, AGN, and Quasars Chandra Images: Normal Galaxies & Starburst Galaxies 

This image is a color-coded picture of the archetypal starburst galaxy M82. It shows the horizontal stellar disk of the galaxy, which harbors its active star formation, and a perpendicular supergalactic wind of ionized gas powered by the energy released in the starburst. To make this image, data from the WIYN 3.5-meter telescope on Kitt Peak were combined with data from the WFPC2 camera on the Hubble Space Telescope. Purple represents emission in ionized hydrogen (H-alpha) and ionized nitrogen, and the green is ionized sulfur in the WIYN data. In the HST image, these colors refer to H-alpha and nitrogen separately. Note the varying angular resolution of the dust lanes in the central part of the superwind on either side of the stellar disk. 
These data are being used in a study of the connection between structures within M82 and its galactic superwind. This image was first presented at the “Essential Science in Hubble’s Final Years” symposium, held 3-6 May 2004 at the Space Telescope Science Institute. 
The WIYN 3.5-meter and 0.9-meter telescopes on Kitt Peak are operated by a consortium of the University of Wisconsin, Indiana University, Yale University, and the National Optical Astronomy Observatory (NOAO). 
Minimum credit line: Mark Westmoquette (University College London), Jay Gallagher (University of Wisconsin-Madison), Linda Smith (University College London), WIYN//NSF, NASA/ESA (for details see Conditions of Use) 

Extragalactic Observations:
Test SNRs and CR acceleration paradigm
CR distributions in regions of high SF
Potential sources of cosmological VHE diffuse backgrounds
CR Re-acceleration at large scales (>10 kpc)
Starburst phenomena & relative influence of central black holes (effect of central radio sources)

## Galaxies In the Local Group

**Notes:**
Extragalactic Observations:
Test SNRs and CR acceleration paradigm
CR distributions in regions of high SF
Potential sources of cosmological VHE diffuse backgrounds
CR Re-acceleration at large scales (>10 kpc)
Starburst phenomena & relative influence of central black holes (effect of central radio sources)

## Andromeda (M31)

- NASA/JPL-Caltech/K. Gordon (University of Arizona)

- Flux (e.g., Diegels et al., 2000 , Pavlidou et al., 2000):
-    >100-MeV-Flux Similar to M82, NGC 253, Arp 220
-     >100-GeV-Flux Is Much Lower (=2.7).

## Andromeda (M31)

- M31 Would Be the *Ultimate *Cosmic Ray Laboratory.(S. Hunter)

**Notes:**
Is diffusive shock acceleration in SNRs or super bubbles the key process in generating CRs below ~ 1015 eV? 
How do cosmic-rays propagate in the magnetic field of a spiral galaxy?

Distance to M31 is 770 kpc.  Superbubbles are 100-1000 pc in diameter (0.4 – 4 arcmin).

## Galaxy Clusters

- (1) Large Scale Structure Formation Shocks

- Voelk & Atoyan 1999, Aph, 11, 73Ryu et al. 2003, ApJ, 593, 599Pfrommer & Ensslin 2004, A&A, 413, 17Kang & Jones 2005, ApJ, 620, 44Berrington & Dermer, 2003, ApJ, 594, 709 Inoue et al., 2006, astro-ph/0507068

## Galaxy Clusters

- (1) Large Scale Structure Formation Shocks

- http://www-theorie.physik.unizh.ch/~moore/pictures.htm

- Voelk & Atoyan 1999, Aph, 11, 73Ryu et al. 2003, ApJ, 593, 599Pfrommer & Ensslin 2004, A&A, 413, 17Kang & Jones 2005, ApJ, 620, 44Berrington & Dermer, 2003, ApJ, 594, 709 Inoue et al., 2006, astro-ph/0507068

- Nearby Clusters (Coma, Perseus, Ophiuchus):
-  Most Emission Comes From 0.5o Ø,
-  Entire Cluster: 4.5o Ø

## Conclusions

- Supermassive Black Holes:
- VERITAS, HESS, MAGIC & GLAST:  Sufficient Sensitivity to Sample Flux <and> Energy Spectrum On Time Scales of Interest.
- GLAST: Deep Population Studies.
- Future GeV/TeV Experiment:
- Identification of GLAST Sources.
- EBL(z).
- Quasar Remnants  -Rays from the Central Engine.
- Star-Burst Galaxies, LIGs, & Galaxy Clusters:
- May Have Hard Energy Spectra.
- May Become Major Science Drivers <If> Detected by Present IACTs.
- Galaxies of Local Group:
- Expected GeV Fluxes Are Low (Soft Energy Spectra).
- Local Group Galaxies and Clusters:
- Can Be Resolved with 0.1o Angular Resolutions.