Uri Keshet / CfA Impact of upcoming high-energy astrophysics experiments Workshop, KAVLI, October 2008

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1 Uri Keshet / CfA Impact of upcoming high-energy astrophysics experiments Workshop, KAVLI, October 008

2 Impact of upcoming high-energy astrophysics experiments Workshop, KAVLI, October 008 Relaxed, cool core clusters Perseus 150 kpc Radio mini-halo Mini halo Mpc 006 CFHT / Coelum 100 kpc X-ray ROSAT (Ettori & Fabian) Central 50 kpc: Radio bubbles Ripples Cold fronts Shocks 37 MHz Ferrari et al. (008)

3 Impact of upcoming high-energy astrophysics experiments Workshop, KAVLI, October 008 Clusters with merger activity 1E Markevitch & Vikhlinin 007 Magellan 6.5m X-ray Some clusters: EUV/hard X-ray IC excess (Coma, Virgo, A56) Bowyer et al. 004, Rephaeli & Gruber 004, Weak lensing 1.3 GHz But no TeV (Perkins et al. 08 )

4 Radio relic - coincident with shock? Impact of upcoming high-energy astrophysics experiments Workshop, KAVLI, October 008

5 Cluster players Baryons in stars: ~3% mass Baryons in hot gas: 5-15% Dark matter Accretion shocks (high M) Merger shocks (low M) CR p + CR e - with γ e <00 Magnetic fields 0.1-3µG MHD turbulence Secondary e - Q s: Constituents, cooling flows, cd coupling, instabilities, halos, mini-halos, relics, A s: cosmology, LSS evolution, plasma & shock physics, galaxy evolution, Impact of upcoming high-energy astrophysics experiments Workshop, KAVLI, October 008

6 Accretion shocks v~1000 km s -1 similar to SNRs. similar physics (after rescaling) for {M,σ -1 }>>1 B structure T upstream ε B U U B kin solar system upstream SNRs virial composition inhomogeneities ( γ 1) Weibel? Blandford & Eichler (1987) Medvedev & Loeb (1999) Impact of upcoming high-energy astrophysics experiments Workshop, KAVLI, October 008 ε B B AGNs, µ-jet / 8π nmc V c GRBs ( rel) A relativistic PWN ωc ω p l r Spitkovsky et al. (004) β sh γ sh sd ( th) L

7 Impact of upcoming high-energy astrophysics experiments Workshop, KAVLI, October 008 Accretion shocks γ γ v~1000 km s -1 similar to SNRs. similar physics (after rescaling) for {M,σ -1 }>>1 e - r sh M,T e - M γ γ ΛCDM SPH simulation γ-rays > 100 MeV 16 о, θ4 Keshet, Waxman, Loeb, Springel & Hernquist (00,003)

8 Model part 1: Dimensional Analysis Halo properties: ρ ( r) σ π Gr ρ( M) 00ρ C ρ ( r ) sh 50 ρc 3 M 5 M& ( M, z) k B r sh σ( M, z) GH( z) f acc Waxman & Loeb (000) Impact of upcoming high-energy astrophysics experiments Workshop, KAVLI, October σ( M, z) G f T µ mpσ ( M, ) T( M, z) z ( M, z) 3 f σ( M, z) r 5 H( z) f acc ~0.1 f T ~0.5 f r ~0.9 Keshet et al. (004) NFW profiles, overdensity, filament heating, Kocsis et al. (005), Pavlidou & Fields (006),

9 Model part t t acc cool r / c L 4 γ H β T yr << t kev sh B 7 m c γ e 1 4 e 3σTuCMB γ yr γ max 1/ 7 T B K 0.1µ G Inverse- Compton: ν L IC ν ( M, z ) 3 N& ( M, z) k T ( M, z) b B ξ e 1 ln γ max Synchrotron: ν L syn ν ( M, z) [ B M z U ] (, ) ξ B sh u cmb 8π ν L IC ν ( M, z) Reproduce 0.1µG ξ B 1% Loeb & Waxman (000) SNR observations Flat (p) spectrum ξ e (.5% 7.5% ) 5% Keshet et al. (003) Impact of upcoming high-energy astrophysics experiments Workshop, KAVLI, October 008

10 γ-ray images >100 MeV θ4 J 10 cm sr s -1-1 >10 GeV θ1 J 10 cm - 9 sr 8. s -1-1 Z M Keshet et al. (003) Impact of upcoming high-energy astrophysics experiments Workshop, KAVLI, October 008

11 Detecting the γ-ray signal 10 0 f r <δ I ν (θ)>1/ /<I ν > N(>F) ξ e 5% GLAST EGRET model F ε f acc f T ξ e IC 10-1 Waxman & Loeb θf r -1 [deg] >Dozen GLAST sources for ξ e >3% Statistical detection F[ph s -1 cm - ] (>100 MeV) 3σ correlation: Abell clusters & EGRET flux (Scharf & Mukherjee 00) Keshet et al. (003); Keshet, Waxman & Loeb (004b) Impact of upcoming high-energy astrophysics experiments Workshop, KAVLI, October 008

12 Impact of upcoming high-energy astrophysics experiments Workshop, KAVLI, October 008 Inverse- Compton spectrum ε dj/dε[kev s -1 cm - sr -1 ] kev EGRET GeV J ξ e WL000 J ξ e f acc f T simulation J ξ e ε[ev] MeV Keshet et al. (003) Keshet, Waxman & Loeb (004b) What is the EGRB? Dermer (007)

13 Previous estimate 1.45± 0.05 I X (Sreekumar et al. 1998) > 100 MeV,units: ph s cm sr EGRB: lower than thought 70% syn ( GHz) 30% gas (1 cm) North K South < 0.5 EGRB upper limit: 1/3 of previous C.L. Keshet, Waxman & Loeb (JCAP 004) Impact of upcoming high-energy astrophysics experiments Workshop, KAVLI, October 008 I X

14 Impact of upcoming high-energy astrophysics experiments Workshop, KAVLI, October 008 Fermi (GLAST)?

15 Impact of upcoming high-energy astrophysics experiments Workshop, KAVLI, October 008 ICM evolution, merger shocks Less important for high energies Difficult! acceleration & magnetization in weak shocks unconstrained need to model feedback effects, turbulence, Analytically: merger trees (Gabici & Blasi 03, Berrington & Dermer, ) Simulations with Cluster shocks: TVD post-processing (Ryu & Kang 08 ) embedded CRs (Miniati 0 ) SPH post-processing (Hoeft et al. 08 ) embedded CRs (Pfrommer, Ensslin, Springel 08 ) combined w/mhd (Dolag & Stasyszyn 08 ) AMR post-processing (Vazza+ 08, Skillman+ 08 )

16 Impact of upcoming high-energy astrophysics experiments Workshop, KAVLI, October 008 Simulations Vazza et al. (008)

17 Impact of upcoming high-energy astrophysics experiments Workshop, KAVLI, October 008 Conclusions Observations and theory: important non-thermal effects in galaxy clusters Highly non-thermal particles: strong accretion shocks, constrained physics ICM evolution: progress, but complicated, unconstrained physics

18 Impact of upcoming high-energy astrophysics experiments Workshop, KAVLI, October 008 What can we learn: Cosmology: Detect clusters in radio, γ-rays directly, by correlations Energy budget Gauge WHIM, IGM magnetic fields Reconstruct LSS Inversion problem: reconstruct merger history form ICM Astro-, plasma and shock physics Feedback, cooling problem Lab for shock acceleration and magnetization Turbulence, instabilities (e.g. thermal driven), draping