ground-based cherenkov: veritas hess cangaroo iii magic magic-2 milagro
DESCRIPTION
Gamma Ray Sources Chuck Dermer Naval Research Laboratory Washington, DC USA TAUP 2007, Sendai, Japan, September 2007. Topics in Astroparticle and Underground Physics. Ongoing revolution in our understanding of g -ray sources. TeV astronomy. GeV astronomy. Ground-based Cherenkov: VERITAS - PowerPoint PPT PresentationTRANSCRIPT
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…