Gamma Ray Sources Chuck Dermer

Naval Research LaboratoryWashington, DC USA

TAUP 2007, Sendai, Japan, September 2007

Ground-based Cherenkov:• VERITAS • HESS• Cangaroo III• MAGIC MAGIC-2• Milagro

Topics in Astroparticle and Underground Physics

Space-based:• EGRET GLAST• AGILE

Ongoing revolution in our understanding of -ray sources

TeV astronomy GeV astronomy

+ multi-wavelength/ multi-messenger information

(talk by W. Hoffman) focus on GeV and extragalactic sources

The Gamma-Ray Sky

Diffuse/unresolved emissions(Quasi)-quiescent radiationsPulsing sources

Flaring sourcesBursting sources

EGRET Detector

Spark Chamber Energy range: ~100 MeV – 5 GeVPointing Instrument (psf ~ 5.7° at 100 MeV)Two week observation: ~106 secField-of-view: ~1/24th of the Full Sky

Two-week detection threshold 1510-8 ph(>100 MeV) cm-2 s-1

(high-latitude sources; background limited)

F Threshold energy flux: 10-10 ergs cm-2 s-1

Energetic Gamma Ray Experiment Telescopeon the Compton Gamma Ray Observatory

Flew 1991 -- 2000

GLAST Detector

LAT Tracker Energy range: ~ 50 MeV – 100 GeVScanning Instrument (psf ~ 3.5° at 100 MeV)Views whole sky every 3 hours Field-of-view: ~1/5th of the Full Sky

One year detection threshold 0.410-8 ph(>100 MeV) cm-2 s-1

(high-latitude sources; background limited)F threshold energy flux: 3 10-12 ergs cm-2 s-1

Gamma Ray Large Area Space Telescope Large Area Telescope + GLAST Burst Monitor

Launch: February 2008(talk by C. Cecchi)

EGRET (> 100 MeV) All-Sky Map

• Requires background cosmic-ray/gas model to find -ray sources

Catalog of Established High Energy (> 100 MeV) Gamma-Ray Sources

High mass binaries/microquasars

GRBs

(Hartman et al. 1999)

(271 Sources, plus 5 GRBs)(66/27 hi/low confidenceAGNs)

+ Radio galaxy (Cen A)

Casandjian & Grenier ‘07

Revised EGRET Catalog

Before:

After:

• 107 3EG sources not confirmed

– most Gould Belt sources• 32 new sources from 9-

year data• GeV/TeV irradiated

cloud "sources"

-Ray Supernova Remnants

• No unambiguous identification of a SNR with EGRET

• SNR maps with HESS– RX J1713.7-3946– Vela Jr– RCW 86

• Cosmic Ray Origin Problem– rays from Compton-

scattered CMB – rays from CR p + p,N 0

• Detection of 0 bump with GLAST

Aharonian et al. 2007

Detection of LMC with EGRET = 19 10-8 ph(>100 MeV) cm-2 s-1

(Sreekumar et al.1992)spectral shape consistent with that

expected from cosmic ray interactions with matter

Scale to local galaxies (SMC, Andromeda)

Starburst Galaxies (M82, NGC 253; 3 Mpc)

IR Luminous Galaxies (Arp 220; 72 Mpc) (Torres 2004)

Normal, Starburst and IR Luminous Galaxies

Clusters of Galaxies

F few10-13 ergs cm-2 s-

1 at 1 TeV

Implies >> years required to detect with a km-scale telescope

UHECRs and secondary rays from clusters? (talk by S. Inoue)

Berrington and Dermer (2005)

Inte

gral

pho

ton

flux

ph(>

E cm

-2 s-1

)

(Armengaud, Sigl, &Miniati 2006)

3C 296

Radio Galaxies and Blazars

3C 279, z = 0.538

L ~1045 x (f/10-10 ergs cm-2 s-1) ergs s-1

Mrk 421, z = 0.031

Cygnus A

L ~5x1048 x (f/10-9 ergs cm-2 s-1) ergs s-1

FR2/FSRQ

FR1/BL LacFR1/2 dividingline at radio power1042 ergs s-1 BL Lacs: optical emission line equivalent

widths < 5 Å

Redshift Distribution of EGRET -Ray Blazars

Standard Blazar Model

• Collimated ejection of relativistic plasma from supermassive black hole

• Relativistic motion accounts for lack of attenuation; superluminal motion; super-Eddington luminosities

• High energy beamed rays made in Compton or photo-hadronic processes

• FSRQs have intense external radiation field from broad line-region gas

Evolution from FSRQ to BL Lac Objects in terms of a reduction of fuel from surrounding gas and dust

FSRQ

BL Lac

Sambruna et al. (1996); Fossati et al. (1998)Böttcher and Dermer (2000)Cavaliere and d’Elia (2000)

Understanding the blazar main sequence

Blazar Main Sequence: Supermassive Black Hole Growth and Evolution

Black Hole Jet Physics

Variability and Black Hole Mass

Energy Source: Accretion vs. Rotation

Two Component Synchrotron/ Compton Leptonic Jet Model

Location of -ray Emission Region

Accretion Disk

SMBH

RelativisticallyCollimated Plasma Outlfows

Observer

BLR clouds

Dusty Torus

Ambient Radiation Fields

BL Lac vs. FSRQ

Hadronic Jet Model

Leptonic Blazar Modeling

z = 0.538

L ~5x1048 x (f/1014 Jy Hz) ergs s-1

Temporally evolving SEDs

Evolution of electron distribution with time: information about acceleration (e.g., loop diagrams);Correlated behavior expected for leptonic emissions

Infer B field, Doppler power, jet power, location

Böttcher et al. 2007

• Infer intrinsic spectrum with EBL absorption • Implied large Doppler factors of TeV blazars• Orphan TeV flares• Linear jets

Aharonian et al., Nature, 2005

Evidence for Anomalous -Ray Components in Blazars

z = 0.186

d ~ 200 Mpc l jet ~ 1 Mpc (lproj = 240 kpc)

Deposition of energy through ultra-high energy neutral beams (Atoyan and Dermer 2003)

Pictor A in X-rays and radio (Wilson et al, 2001 ApJ 547)

Pictor APictor A

Sreekumar et al. (1998)

Blazars as High Energy Hadron Accelerators

astro-ph/0610195

Synchrotron and IC fluxes from the pair-photon cascade for the Feb 1996 flare of 3C279

(3C 279)

dotted - CRs injected during the flare; solid - neutrons escaping from the blob, dashed - neutrons escaping from Broad Line Region (ext. UV) dot-dashed - rays escaping external UV field (produced by neutrons outside the blob)3dot-dashed- Protons remaining in the blob at l = RBLR

Powerful blazars / FR-II Neutrons with En > 100 PeV and rays with E > 1PeV take away ~ 5-10 % of the total WCR(E > 1015eV=1 PeV) injected at R<RBLR

UHE neutrons & -rays: energy & momentum transport from AGN core

UHE -ray pathlengths in CMBR: l ~ 10 kpc - 1Mpc for the En ~ 1016 - 1019 eV

• Neutron decay pathlength: ld (n) = 0 c n , (0 ~ 900 s)

ld ~ 1 kpc - 1Mpc

for the predicted E~ 1017 - 1020 eV

•High redshift jets: photomeson processes on neutrons turn on

solid: z = 0 dashed: z = 0.5

Detection of single high-energy from blazars neutral beams could power large-scale jets

Neutrinos: expected fluences/numbers

Expected - fluences calculated for 2 flares, in 3C 279 and Mkn 501, assuming proton aceleration rate Qprot(acc) = Lrad(obs) ; red curves - contribution due to internal photons, green curves - external component (Atoyan & Dermer 2003) Expected numbers of for IceCube-scale detectors, per flare:● 3C 279: N = 0.35 for = 6 (solid curve) and N = 0.18 for = 6 (dashed) Mkn501: N = 1.2 10-5 for = 10 (solid) and N = 10-5 for = 25 (dashed) (`persistent') -level of 3C279 ~ 0.1 F (flare) , ( + external UV for p ) N ~ few - several per year can be expected from poweful HE FSRQ blazars. N.B. : all neutrinos are expected at E>> 10 TeV

GRBs

Multiple Classes1. Long duration GRBs2. X-ray flashes3. Low-luminosity GRBs4. Short Hard Class of GRBs

Long Duration GRBsMassive Star OriginCollapse to Newly Formed Black HolePrompt phase: internal or external relativistic shocksAfterglow phase: external shockMean redshift: ~1 (BATSE), ~2

(Swift)GRB/Supernova connection

Kouveliotou et al. 1993

Anomalous -ray Emission Components in GRBs

Long (>90 min) -ray emission

(Hurley et al. 1994)

Anomalous High-Energy Emission Components in GRBsEvidence for Second Component from BATSE/TASC Analysis

Hard (-1 photon spectral index) spectrum during

delayed phase

−18 s – 14 s

14 s – 47 s

47 s – 80 s80 s – 113 s

113 s – 211 s

100 MeV

1 MeV

(González et al. 2003)

GRB 941017

Second Gamma-ray Component in GRBs: Other Evidence

Delayed -ray emission from superbowl burst GRB 930131Low significance Milagrito detection of GRB 970417A(Requires low-redshift GRB to avoid attenuation by diffuse IR background)

Atkins et al. 2002Sommer et al. 1994

Photon and Neutrino Fluence during Prompt Phase

Hard -ray emission component from hadronic-induced electromagnetic cascade radiation inside GRB blast wave Second component from outflowing high-energy neutral beam of neutrons, -rays, and neutrinos

e

pnep

2

),,(0

Nonthermal BaryonLoading Factor fb = 1

tot = 310-4 ergs cm-2

= 100

Gamma-Ray Bursts as Sources of High-Energy Cosmic RaysSolution to Problem of the Origin of Ultra-High Energy Cosmic Rays

(Wick, Dermer, and Atoyan 2004)

(Waxman 1995, Vietri 1995, Dermer 2002)

Hypothesis requires that GRBs can accelerate cosmic rays to energies > 1020 eV

Injection rate density determined by GRB formation rate (= SFR?)

GZK cutoff from photopion processes with CMBR

Ankle formed by pair production effects

(Berezinsky and Grigoreva 1988,Berezinsky, Gazizov, and Grigoreva 2005)

Star Formation Rate: Astronomy Input

Hopkins & Beacom 2006

USFR

LSFRHB06

SFR6,pre-Swift

Le & Dermer 2006

SFR6,Swift

SFR6,pre-Swift

Fitting Redshift and Opening-Angle Distribution

Cosmogenic GZK -Ray Intensity

(Le & Dermer 2006)

Der

mer

, unp

ublis

hed

calc

ulat

ions

, 200

7

astro-ph/0611191

Neutrinos from GRBs in the Collapsar Model

(~2/yr)

Nonthermal Baryon Loading Factor fb = 20

Dermer & Atoyan 2003

requires Large Baryon-Loading

(diffuse background from GRBs: talk by K. Murase)

Sreekumar et al. (1998)

Unresolved -Ray Background

Strong, Moskalenko, & Reimer (2000)

Data:

Star-forming galaxies (Pavlidou & Fields 2002) Starburst galaxies (Thompson et al. 2006) Pulsar contribution near 1 GeVGalaxy cluster shocks (Keshet et al. 2003, Blasi Gabici & Brunetti 2007)Dark matter contribution (talk by Bergstrom)

BL Lacs: ~2 - 4% (at 1 GeV) FSRQs: ~ 10 - 15%

astro-ph/0610195

GeV -ray Astronomy: Some Important Problems

Particle acceleration theory

Origin of galactic cosmic rays

Jet physics, differences between radio/-ray black hole sources

Blazar demographics

Search for hadronic emission components: Acceleration of UHECRs in extragalactic sources (predictions for astronomy)

Origin of diffuse/unresolved -ray background

Summary

Waiting for GLAST…