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Thermal and non-thermal emission from galaxy clusters: X-ray and LOFAR observations

Chiara Ferrari Observatoire de la Côte d’Azur, Nice, FRANCE. Thermal and non-thermal emission from galaxy clusters: X-ray and LOFAR observations. Outline of the talk. Diffuse radio emission in clusters Radio/X-ray comparison Importance for the study of radio halos & relics Open questions

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Thermal and non-thermal emission from galaxy clusters: X-ray and LOFAR observations

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  1. Chiara Ferrari Observatoire de la Côte d’Azur, Nice, FRANCE Thermal and non-thermal emission from galaxy clusters: X-ray and LOFAR observations LOFAR Wokshop

  2. LOFAR Wokshop Outline of the talk • Diffuse radio emission in clusters • Radio/X-ray comparison • Importance for the study of radio halos & relics • Open questions • Study of non-thermal emission with LOFAR • Conclusions

  3. LOFAR Wokshop Diffuse radio emission in clusters • S(ν)ν-α • α 1 • Relativistic electrons: γ>>1000 • Magnetic fields: ~ 0.1 – 1 μGauss A2163: VLA observations Feretti et al. 2001, 2004

  4. LOFAR Wokshop • Radio halos: • extended ( 1 Mpc) radio sources • at the cluster centre • regular morphology (~X-ray) • Radio mini halos: • smaller sources ( 500 kpc) • at the centre of clusters with: • AGN • cooling-core • Radio relics: • extended (~1 Mpc) radio sources • cluster outskirts • elongated morphology + polarised Feretti, Fusco-Femiano et al. 2001 A2163: XMM + VLA Gitti, Ferrari et al. 2007 X-ray images + radio contours Ferrari, Arnaud et al. 2006 RX J1347-11: XMM + VLA A521: Chandra + VLA

  5. LOFAR Wokshop 30 arcmin z ~ 0.2 A2163: radio halo Feretti et al. 2001 Dimensions: ~1 Mpc Crossing time e-: ~9.5 Gyr Life time of e-: ~0.1 Gyr Origin of relativistic electrons

  6. LOFAR Wokshop credits: C. Pfrommer • Primary models: (re-)acceleration due to shocks/turbulence • (e.g. Enßlin et al. 1998; Brunetti et al. 2001, 2004; Cassano & Brunetti 2005) • Secondary models:hadronic collisions of relativistic p+with the ICM • (e.g. Dennison 1980; Blasi & Colafrancesco 1999; Dolag & Enßlin 2000) • Prim. + Sec. models: a combination of the two • (e.g. Pfrommer et al. 2008; Cassano et al. 2008) Origin of relativistic electrons

  7. LOFAR Wokshop Measure of intracluster magnetic fieldsDiscrepant results • Equipartition assumption: ~0.1 – 1 μGauss • Compton scattering of CMB photons: ~0.1 – 0.3 μGauss • Faraday rotation measure: ~1 - 10 μGauss • X-ray analysis of cold fronts: ~10 μGauss

  8. LOFAR Wokshop Radio + Thermal X-ray Radio / X-ray comparison Nature of the non-thermal cluster component (1) • Radio + Non-Thermal X-ray

  9. LOFAR Wokshop Radio + Thermal X-ray A2163: Feretti et al. 2001 XMM (image) + VLA (contours) A2255: Govoni et al. 2001 Radio / X-ray comparison Nature of the non-thermal cluster component (1) • Radio X-ray morphologies

  10. LOFAR Wokshop Radio + Thermal X-ray A2256: Clarke & Enßlin 2006 Chandra (image) + VLA (contours) Radio / X-ray comparison Nature of the non-thermal cluster component (1) • Radio X-ray morphologies • Halos & Relics  Cluster mergers

  11. LOFAR Wokshop Radio + Thermal X-ray Brunetti et al. 2007 Radio / X-ray comparison Nature of the non-thermal cluster component (1) • Radio X-ray morphologies • Halos & Relics  Cluster mergers • P1.4GHz LX (TX )

  12. LOFAR Wokshop Radio + Thermal X-ray A665: Feretti et al. 2004 Radio / X-ray comparison Nature of the non-thermal cluster component (1) • Radio X-ray morphologies • Halos & Relics  Cluster mergers • P1.4GHz LX (TX ) • Radio spectral index  Distance from the X-ray centroid

  13. LOFAR Wokshop Radio + Thermal X-ray A773: Orrù et al. 2007  327 MHz1400 MHZ TX (keV) Radio / X-ray comparison Nature of the non-thermal cluster component (1) • Radio X-ray morphologies • Halos & Relics  Cluster mergers • P1.4GHz LX (TX ) • Radio spectral index  Distance from the X-ray centroid • Radio spectral index TX

  14. LOFAR Wokshop TICM + radio contours Govoni et al. 2004 A773 Giant radio halos & relics: cluster mergers Johnston-Hollitt et al. 2002 Relics  ICM shocks A3667 X-ray + radio contours Giant halos  turbulence

  15. LOFAR Wokshop Radio + Thermal X-ray XMM (image) + VLA (contours) TX A773: Orrù et al. 2007  327 MHz1400 MHZ X-ray surf. bright. Radio surf. bright. TX (keV) Radius RX J1347: Gitti, Ferrari et al. 2007 Radio / X-ray comparison Nature of the non-thermal cluster component (1) • Radio X-ray morphologies • Halos & Relics  Cluster mergers • P1.4GHz LX (TX ) • Radio spectral index  Distance from the X-ray centroid • Radio spectral index TX • Mini-halos AGN + cooling-core

  16. LOFAR Wokshop Radio + Thermal X-ray ROSAT (image) + VLA (contours) A 2255: Govoni et al. 2001 6 cm 3.6 cm Radio / X-ray comparison Nature of the non-thermal cluster component (2) • Magnetic field mesurements • Rotation Measure • Cold front analysis

  17. LOFAR Wokshop Radio + Thermal X-ray Chandra A 3667: Vikhlinin et al. 2001 Magnetic layer Radio / X-ray comparison Nature of the non-thermal cluster component (2) • Magnetic field mesurements • Rotation Measure • Cold front analysis

  18. LOFAR Wokshop Chandra (red/yellow) + VLA (blue & contours) Beppo-SAX HXR excess Fusco-Femiano et al. 2000 Clarke & Ensslin 2006 Radio / X-ray comparison Nature of the non-thermal cluster component (3) Radio + Non-thermal X-ray • Relativistic electrons: γ>>1000 • CMB photons Inverse Compton emission (hard X-ray &  domain) A 2256 e- energy distribution synchrotron emissivity IC flux

  19. LOFAR Wokshop Main limits of current analyses • Low statistics •  60 clusters with detected diffuse radio emission • < 15 clusters with detected hard X-ray excess • < 10 clusters with detailed radio spectral index maps • Lack of current intruments’ sensitivity • Distribution on the Lradiovs. LX plane: bimodal or not? • Radio relics: associated to ICM shocks? • Low significance of the hard X-ray excess ( < 5) • Systematic errors in the background level • Lack of spatial information & ICMmulti-temperature plasma • Contamination by AGNs

  20. LOFAR Wokshop Radio / X-ray comparison : some open questions • Origin of relativistic particles • Primary models (  halos & relics  new tracers of large-scale structure formation) • Secondary models • Primary + Secondary (Pfrommer et al. 2008: unified model for all halos and relics) • Intra-cluster magnetic fields • Intensity & Structure • Non-thermal cluster component • Effects on the thermal ICM (energy budget, heat conduction, overall pressure) • Detection of the non-thermal HXR emission •  e.g. Fusco-Femiano et al. 1999, 2004, 2007 (Beppo-SAX), Repaheli et al. 1999, 2002 (RXTE), Eckert et al. 2008 (INTEGRAL), ... • e.g. Rossetti & Molendi 2004 (Beppo-SAX), Eckert et al. 2007 (INTEGRAL), Ota et al. 2008 (Suzaku), Ajello et al. 2008 (Swift/BAT), ...

  21. LOFAR Wokshop Study of non-thermal emission with LOFAR:multi-wavelength comparison coll.: Ferrari, Arnaud, Feretti, Tagger, Aghanim, ... & «Clusters of galaxies» working group in the« Extragalactic Survey » Key Project • Statistical studies of diffuse radio emissionvs. global cluster porperties(mass, dynamical state, LX, ...) & z • (based on « All Sky Survey » – Röttgering et al. 2008) • Detailed radio/X-ray comparisons for a cluster sub-sample • Thermal X-ray emission: Chandra & XMM • Non-thermal X-ray emission: Simbol-X • (based on «Deep Survey» – Röttgering et al. 2008)

  22. LOFAR Wokshop Ferrari 2008 Brightness profile Brunetti et al. 2007 1023 W/Hz 1024 W/Hz 1025 W/Hz 1026 W/Hz L1.4GHz =1 Cassano et al. 2007 Diffuse radio sources with LOFAR

  23. LOFAR Wokshop  = 1 Rhalo as a function of P1.4GHz 80% of flux detected at 10  sig. level Statistical studies Diffuse radio emission vs. global cluster properties & z All Sky Survey sensitivity limits – Röttgering et al. 2008 Ferrari 2008 LX z

  24. LOFAR Wokshop  = 1 Rhalo as a function of P1.4GHz 80% of flux detected at 10  sig. level  = 1.5 Rhalo as a function of P1.4GHz 50% of flux detected at 10  sig. level Statistical studies Diffuse radio emission vs. global cluster properties & z All Sky Survey sensitivity limits – Röttgering et al. 2008 Ferrari 2008 LX z

  25. LOFAR Wokshop  = 1 Rhalo as a function of P1.4GHz 80% of flux detected at 10  sig. level  = 1 Rhalo = 0.5 Mpc 80% of flux detected at 10  sig. level Statistical studies Diffuse radio emission vs. global cluster properties & z All Sky Survey sensitivity limits – Röttgering et al. 2008 Ferrari 2008 LX z

  26. LOFAR Wokshop  = 1 Rhalo as a function of P1.4GHz 80% of flux detected at 10  sig. level  = 1 Rhalo = 0.5 Mpc 50% of flux detected at 10  sig. level Statistical studies Diffuse radio emission vs. global cluster properties & z All Sky Survey sensitivity limits – Röttgering et al. 2008 Ferrari 2008 LX z

  27. LOFAR Wokshop  = 1 Rhalo as a function of P1.4GHz 80% of flux detected at 10  sig. level  = 1 Rhalo = 0.5 Mpc 80% of flux detected at 20  sig. level Statistical studies Diffuse radio emission vs. global cluster properties & z All Sky Survey sensitivity limits – Röttgering et al. 2008 Ferrari 2008 LX z

  28. LOFAR Wokshop  = 1 Rhalo as a function of P1.4GHz 80% of flux detected at 10  sig. level  = 1.5 Rhalo as a function of P1.4GHz 50% of flux detected at 10  sig. level Statistical studies Diffuse radio emission vs. global cluster properties & z All Sky Survey sensitivity limits – Röttgering et al. 2008 Ferrari 2008 LX z

  29. LOFAR Wokshop Radio luminosity of diffuse radio sources vs. • Physical properties of their host systems (dyn. state, mass, LX, TX) • Redshift (possible connections with the Planck cluster catalogue) Statistical studies Diffuse radio emission vs. global cluster properties & z Ferrari 2008  = 1.0 (e.g. Orrù et al. 2007) Rhaloas a function of P1.4GHz 80% of flux detected at 20  s.l. All Sky Survey (Röttgering et al. 2008)

  30. LOFAR Wokshop Radio luminosity of diffuse radio sources vs. • Physical properties of their host systems (dyn. state, mass, LX, TX) • Redshift (possible connections with the Planck cluster catalogue)  = 1.5 (e.g. Brentjens 2008) Rhaloas a function of P1.4GHz 80% of flux detected at 20  s.l. All Sky Survey (Röttgering et al. 2008)  = 1.0 (e.g. Orrù et al. 2007) Rhaloas a function of P1.4GHz 80% of flux detected at 20  sig. level Statistical studies Diffuse radio emission vs. global cluster properties & z Ferrari 2008  = 1.0 (e.g. Orrù et al. 2007) Rhaloas a function of P1.4GHz 80% of flux detected at 20  s.l. All Sky Survey (Röttgering et al. 2008)

  31. LOFAR Wokshop Detailed radio/X-ray comparisons Deep Survey sensitivity limits – Röttgering et al. 2008 Adapted from Cassano et al. 2006 • 30 MHz • Resolution ~ 20 arcsec • 20 detection - 80% of the radio flux Ferrari 2008

  32. LOFAR Wokshop z = 0.1 Detailed radio/X-ray comparisons Deep Survey sensitivity limits – Röttgering et al. 2008 Adapted from Cassano et al. 2006 • 30 MHz • Resolution ~ 20 arcsec • 20 detection - 80% of the radio flux Ferrari 2008

  33. LOFAR Wokshop z = 0.2 Detailed radio/X-ray comparisons Deep Survey sensitivity limits – Röttgering et al. 2008 Adapted from Cassano et al. 2006 • 30 MHz • Resolution ~ 20 arcsec • 20 detection - 80% of the radio flux Ferrari 2008

  34. LOFAR Wokshop z = 0.3 Detailed radio/X-ray comparisons Deep Survey sensitivity limits – Röttgering et al. 2008 Adapted from Cassano et al. 2006 • 30 MHz • Resolution ~ 20 arcsec • 20 detection - 80% of the radio flux Ferrari 2008

  35. LOFAR Wokshop z = 0.4 Detailed radio/X-ray comparisons Deep Survey sensitivity limits – Röttgering et al. 2008 Adapted from Cassano et al. 2006 • 30 MHz • Resolution ~ 20 arcsec • 20 detection - 80% of the radio flux Ferrari 2008

  36. LOFAR Wokshop z = 0.5 Detailed radio/X-ray comparisons Deep Survey sensitivity limits – Röttgering et al. 2008 Adapted from Cassano et al. 2006 • 30 MHz • Resolution ~ 20 arcsec • 20 detection - 80% of the radio flux Ferrari 2008

  37. LOFAR Wokshop z = 0.6 Detailed radio/X-ray comparisons Deep Survey sensitivity limits – Röttgering et al. 2008 Adapted from Cassano et al. 2006 • 30 MHz • Resolution ~ 20 arcsec • 20 detection - 80% of the radio flux Ferrari 2008

  38. LOFAR Wokshop z = 0.8 Detailed radio/X-ray comparisons Deep Survey sensitivity limits – Röttgering et al. 2008 Adapted from Cassano et al. 2006 • 30 MHz • Resolution ~ 20 arcsec • 20 detection - 80% of the radio flux Ferrari 2008

  39. LOFAR Wokshop z = 1.0 Detailed radio/X-ray comparisons Deep Survey sensitivity limits – Röttgering et al. 2008 Adapted from Cassano et al. 2006 • 30 MHz • Resolution ~ 20 arcsec • 20 detection - 80% of the radio flux Ferrari 2008

  40. LOFAR Wokshop Ferrari 2008 LX z Detailed radio/X-ray comparisons Adapted from Cassano et al. 2006 z=0.2 LOFAR estimates: Ferrari 2008 z=0.1 • 30 MHz • Resolution ~ 20 arcsec • 20 detection • 80% of the radio flux

  41. LOFAR Wokshop Ferrari 2008 LX • Simbol-X • Spectro-Imager • 0.5-80 keV • ~15“ angular resolution • ~12‘ F.o.V. z Detailed radio/X-ray comparisons Adapted from Cassano et al. 2006 • 30 MHz • Resolution ~ 20 arcsec • 20 detection • 80% of the radio flux z=0.2 LOFAR estimates: Ferrari 2008 z=0.1

  42. LOFAR Wokshop Brunetti et al. 2007b F 60-100 keV = 10-13 erg cm-2 s-1 5 x10-12 erg cm-2 s-1 # clusters with detected HXR 10-12 erg cm-2 s-1 B=0.2 G Ferrari 2008 LX B=0.2 G B=2.0 G Simbol-X limits z Detailed radio/X-ray comparisons Adapted from Cassano et al. 2006 z=0.2 LOFAR estimates: Ferrari 2008 z=0.1 • 30 MHz • Resolution ~ 20 arcsec • 20 detection • 80% of the radio flux

  43. LOFAR Wokshop Optimal for the detection of radio relics A2163 (z~0.2) + Simbol-X F.o.V Ferrari 2008 LX Arnaud 2008 z Detailed radio/X-ray comparisons @ z  0.2 !!! Adapted from Cassano et al. 2006 z=0.2 LOFAR estimates: Ferrari 2008 z=0.1 • 30 MHz • Resolution ~ 20 arcsec • 20 detection • 80% of the radio flux

  44. LOFAR Wokshop • + Complementary studies • Statistical studies : e.g. possible comparison with Planck cluster catalogue • Detailed studies : e.g. energetics of the ICM & AGN feedback Conclusions Galaxy clusters  hierarchical scenario of structure formation  Physics of formation and evolution of galaxy clusters  Nature and origin of the non-thermal cluster component • Statistical studies : halos/relics presence & luminosity • vs. • global clusters properties (e.g. mass, dyn. state) & z • Detailed studies : radio emission in galaxy clusters • vs. • thermal and non-thermal X-ray emission

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