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Explore the potential of Simbol X in probing the characteristics of galaxy clusters, with a focus on non-thermal emission and shocks. Learn about key insights that can be gained from merging clusters such as A1644, A399, and A754. Discover how Simbol X can enhance our understanding of cool cores and non-thermal phenomena in objects like Perseus. Delve into the significance of background derivation in radio and X-ray measurements for accurate B-field estimation and hard tail detection.
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Galaxy Clusters& Simbol X Silvano Molendi (IASF/INAF)
What can we learn about GC with Simbol X • 10-60 keV Non thermal emission shocks • 2-10 keV shocks cluster outer regions metal abundances It depends, 1 major issue: Background
Deriving B from radio + X-rays Some clusters present diffuse synchrotron emission (radio halos) Cosmic Microwave Background Photons will interact with the radio emitting electrons and be inverse compton scattered to high energies, where they can be detected. Joint radio & X-ray measurements could lead to an independent and firmer measurement of the B field
A SAMPLE OF MERGING CLUSTERS A1644 A1750 A119 A1367 A2255 A2256 A2319 A3266 A3376 A3560 A401 A3562 A3558 A3667 A399 A1060 COMA A576 A85 A754 XMM IMAGES (0.4-2 keV) • Intermediate redshift merging systems • 0.05 < z < 0.15 (not too near FOV not too far) • Host radio halos or relics • Previous hard tail detection • About 10 objects Rossetti Phd Thesis
An example A3667 • z = 0.053 • Radio relics • Major merger • B field ~ 4 μG from Faraday rot. meas.
A3667 Assume B field from Faraday rotation measures. Nomimal detection at 99.5% with simple simulation. Note however: • Detection below 20 keV where hard tail competes with thermal emission.. • NT emission fills FOV, non standard bkg treatment required. Control and charcterization of bkg is key issue
A3667 • If estimates of B field from radio correct: place tighter upper limit on hard tail, possibily detect it • If B from radio is overestimated detection and characterization
Which Objects • Cool Cores, recent evidence of non-thermal emission in Perseus (Fabian et al. 2006, Molendi 2006) • Emission presumably from the mini radio-halo observed in Perseus
The EPIC spectrum The observed spectrum is broader than a single thermal component.
Non-thermal emission in CC • Size of putative emission region ~ few sq. arcmin • Emission is intense • Perseus easy with Simbol X • Other, similar objects also possible
Shock in 1E0657 Best (only) example of shock: “Bullet Cluster” Core of sub-structure allready gone through cluster Markevitch et al 2001.
The 2-10 keV band • pnNXB is 5x10-3 cts/s/cm2/keV(UHB) • SDDNXB is 3x10-5 cts/s/cm2/keV More than 100 times smaller! • If this can be achieved SDD will be most sensitive 2-10 keV experiment to low SB emission ever! Surveys, GC, SNR
The 2-10 keV band • Numbers a little optimistic how much can they be relaxed? ~ factor 3 • SDD NXB 1x10-4 cts/s/cm2/keV 50 times smaller than pn Taking into account the different focal lengths SDD bkg per arcmin2 still a factor 7 better than pn, with approx. same eff. areas & below CXB
Summary • Simbol X may address important open questions on GC • Non-thermal emission in merging objects: • If B field is 0.2-0.5 μG as implied by detections, CZT should have no difficulty in performing robust measurements on a handful of objects. • If B is 2-5 μG, as indicated by Faraday rotation measurements, CZT will provide tighter upper limits on hard tail. • Non-thermal emission in Cool Cores: • Characterization of Perseus HT should not pose a problem • Characterization of T jump in Bullet Cluster Schock • In 2-10 keV band everything depends on NXB intensity