Hamburg, 18 September 2008 LOFAR Wokshop1/44 Thermal and non-thermal emission from galaxy clusters: X-ray and LOFAR observations Chiara Ferrari Observatoire de la Côte d’Azur, Nice, FRANCE

Hamburg, 18 September 2008 LOFAR Wokshop2/44 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

Hamburg, 18 September 2008 LOFAR Wokshop3/44 Diffuse radio emission in clusters A2163: VLA observations Feretti et al. 2001, 2004 S( ν )  ν -α α  1 Relativistic electrons: γ>>1000 Magnetic fields: ~ 0.1 – 1 μGauss

Hamburg, 18 September 2008 LOFAR Wokshop4/44 X-ray images + radio contours Feretti, Fusco-Femiano et al A2163: XMM + VLA Ferrari, Arnaud et al A521: Chandra + VLA Radio relics: extended (~1 Mpc) radio sources cluster outskirts elongated morphology + polarised Gitti, Ferrari et al RX J : XMM + VLA Radio mini halos: smaller sources (  500 kpc) at the centre of clusters with:  AGN  cooling-core Radio halos: extended (  1 Mpc) radio sources at the cluster centre regular morphology (~X-ray)

Hamburg, 18 September 2008 LOFAR Wokshop5/44 Origin of relativistic electrons Dimensions: ~1 Mpc Crossing time e - : ~9.5 Gyr Life time of e - : ~0.1 Gyr A2163: radio halo Feretti et al arcmin z ~ 0.2

Hamburg, 18 September 2008 LOFAR Wokshop6/44 Origin of relativistic electrons 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) credits: C. Pfrommer

Hamburg, 18 September 2008 LOFAR Wokshop7/44 Measure of intracluster magnetic fields Discrepant results Equipartition assumption: ~ 0.1 – 1 μGauss Compton scattering of CMB photons: ~ 0.1 – 0.3 μGauss Faraday rotation measure: ~ μGauss X-ray analysis of cold fronts: ~ 10 μGauss

Hamburg, 18 September 2008 LOFAR Wokshop8/44 Radio / X-ray comparison Nature of the non-thermal cluster component (1) Radio + Thermal X-ray Radio + Non-Thermal X-ray

Hamburg, 18 September 2008 LOFAR Wokshop9/44 Radio / X-ray comparison Nature of the non-thermal cluster component (1) Radio + Thermal X-ray  Radio  X-ray morphologies A2163: Feretti et al XMM (image) + VLA (contours) A2255: Govoni et al. 2001

Hamburg, 18 September 2008 LOFAR Wokshop10/44 Radio / X-ray comparison Nature of the non-thermal cluster component (1) Radio + Thermal X-ray  Halos & Relics  Cluster mergers  Radio  X-ray morphologies A2256: Clarke & Enßlin 2006 Chandra (image) + VLA (contours)

Hamburg, 18 September 2008 LOFAR Wokshop11/44 Radio / X-ray comparison Nature of the non-thermal cluster component (1) Radio + Thermal X-ray  Halos & Relics  Cluster mergers  P 1.4GHz  L X (T X )  Radio  X-ray morphologies Brunetti et al. 2007

Hamburg, 18 September 2008 LOFAR Wokshop12/44 Radio / X-ray comparison Nature of the non-thermal cluster component (1) Radio + Thermal X-ray  Halos & Relics  Cluster mergers  P 1.4GHz  L X (T X )  Radio  X-ray morphologies  Radio spectral index  Distance from the X-ray centroid A665: Feretti et al. 2004

Hamburg, 18 September 2008 LOFAR Wokshop13/44 Radio / X-ray comparison Nature of the non-thermal cluster component (1) Radio + Thermal X-ray  Halos & Relics  Cluster mergers  P 1.4GHz  L X (T X )  Radio  X-ray morphologies  Radio spectral index  Distance from the X-ray centroid  Radio spectral index  T X A773: Orrù et al  327 MHz 1400 MHZ T X (keV)

Hamburg, 18 September 2008 LOFAR Wokshop14/44 Giant radio halos & relics: cluster mergers Johnston-Hollitt et al Relics  ICM shocks Giant halos  turbulence A3667 X-ray + radio contours Govoni et al A773 T ICM + radio contours

Hamburg, 18 September 2008 LOFAR Wokshop15/44 Radio / X-ray comparison Nature of the non-thermal cluster component (1) Radio + Thermal X-ray  Halos & Relics  Cluster mergers  P 1.4GHz  L X (T X )  Radio  X-ray morphologies  Radio spectral index  Distance from the X-ray centroid  Radio spectral index  T X  Mini-halos  AGN + cooling-core A773: Orrù et al  327 MHz 1400 MHZ T X (keV) RX J1347: Gitti, Ferrari et al XMM (image) + VLA (contours) TXTX X-ray surf. bright. Radio surf. bright. Radius

Hamburg, 18 September 2008 LOFAR Wokshop16/44 Radio / X-ray comparison Nature of the non-thermal cluster component (2)  Magnetic field mesurements  Rotation Measure  Cold front analysis Radio + Thermal X-ray 6 cm3.6 cm A 2255: Govoni et al ROSAT (image) + VLA (contours)

Hamburg, 18 September 2008 LOFAR Wokshop17/44 Radio / X-ray comparison Nature of the non-thermal cluster component (2)  Magnetic field mesurements  Rotation Measure  Cold front analysis Radio + Thermal X-ray A 3667: Vikhlinin et al Chandra Magnetic layer

Hamburg, 18 September 2008 LOFAR Wokshop18/44 Chandra (red/yellow) + VLA (blue & contours) Clarke & Ensslin 2006  Relativistic electrons: γ>>1000  CMB photons Inverse Compton emission (hard X-ray &  domain) Radio / X-ray comparison Nature of the non-thermal cluster component (3) Radio + Non-thermal X-ray e - energy distribution synchrotron emissivity IC flux HXR excess Fusco-Femiano et al Beppo-SAX A 2256

Hamburg, 18 September 2008 LOFAR Wokshop19/44 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 L radio vs. L X 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

Hamburg, 18 September 2008 LOFAR Wokshop20/44 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 (INTEGRAL),...  e.g. Rossetti & Molendi 2004 (Beppo-SAX), Eckert et al (INTEGRAL), Ota et al (Suzaku), Ajello et al (Swift/BAT),... Radio / X-ray comparison : some open questions

Hamburg, 18 September 2008 LOFAR Wokshop21/44 Study of non-thermal emission with LOFAR: multi-wavelength comparison Statistical studies of diffuse radio emission vs. global cluster porperties (mass, dynamical state, L X,...) & 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) coll.: Ferrari, Arnaud, Feretti, Tagger, Aghanim,... & «Clusters of galaxies» working group in the « Extragalactic Survey » Key Project

Hamburg, 18 September 2008 LOFAR Wokshop22/44 Diffuse radio sources with LOFAR Brunetti et al Cassano et al Brightness profile W/Hz W/Hz W/Hz W/Hz Ferrari 2008 L1.4GHz  =1

Hamburg, 18 September 2008 LOFAR Wokshop23/44 Statistical studies Diffuse radio emission vs. global cluster properties & z All Sky Survey sensitivity limits – Röttgering et al  = 1 R halo as a function of P 1.4GHz 80% of flux detected at 10  sig. level LXLX z Ferrari 2008

Hamburg, 18 September 2008 LOFAR Wokshop24/44 Statistical studies Diffuse radio emission vs. global cluster properties & z All Sky Survey sensitivity limits – Röttgering et al  = 1 R halo as a function of P 1.4GHz 80% of flux detected at 10  sig. level  = 1.5 R halo as a function of P 1.4GHz 50% of flux detected at 10  sig. level LXLX z Ferrari 2008

Hamburg, 18 September 2008 LOFAR Wokshop25/44 Statistical studies Diffuse radio emission vs. global cluster properties & z All Sky Survey sensitivity limits – Röttgering et al  = 1 R halo as a function of P 1.4GHz 80% of flux detected at 10  sig. level  = 1 R halo = 0.5 Mpc 80% of flux detected at 10  sig. level LXLX z Ferrari 2008

Hamburg, 18 September 2008 LOFAR Wokshop26/44 Statistical studies Diffuse radio emission vs. global cluster properties & z All Sky Survey sensitivity limits – Röttgering et al  = 1 R halo as a function of P 1.4GHz 80% of flux detected at 10  sig. level  = 1 R halo = 0.5 Mpc 50% of flux detected at 10  sig. level LXLX z Ferrari 2008

Hamburg, 18 September 2008 LOFAR Wokshop27/44 Statistical studies Diffuse radio emission vs. global cluster properties & z All Sky Survey sensitivity limits – Röttgering et al  = 1 R halo as a function of P 1.4GHz 80% of flux detected at 10  sig. level  = 1 R halo = 0.5 Mpc 80% of flux detected at 20  sig. level LXLX z Ferrari 2008

Hamburg, 18 September 2008 LOFAR Wokshop28/44 Statistical studies Diffuse radio emission vs. global cluster properties & z All Sky Survey sensitivity limits – Röttgering et al  = 1 R halo as a function of P 1.4GHz 80% of flux detected at 10  sig. level  = 1.5 R halo as a function of P 1.4GHz 50% of flux detected at 10  sig. level LXLX z Ferrari 2008

Hamburg, 18 September 2008 LOFAR Wokshop29/44 Statistical studies Diffuse radio emission vs. global cluster properties & z  = 1.0 (e.g. Orrù et al. 2007) R halo as a function of P 1.4GHz 80% of flux detected at 20  s.l. All Sky Survey (Röttgering et al. 2008) Radio luminosity of diffuse radio sources vs. Physical properties of their host systems (dyn. state, mass, L X, T X ) Redshift (possible connections with the Planck cluster catalogue) Ferrari 2008

Hamburg, 18 September 2008 LOFAR Wokshop30/44 Statistical studies Diffuse radio emission vs. global cluster properties & z  = 1.0 (e.g. Orrù et al. 2007) R halo as a function of P 1.4GHz 80% of flux detected at 20  s.l. All Sky Survey (Röttgering et al. 2008) Radio luminosity of diffuse radio sources vs. Physical properties of their host systems (dyn. state, mass, L X, T X ) Redshift (possible connections with the Planck cluster catalogue)  = 1.0 (e.g. Orrù et al. 2007) R halo as a function of P 1.4GHz 80% of flux detected at 20  sig. level  = 1.5 (e.g. Brentjens 2008) R halo as a function of P 1.4GHz 80% of flux detected at 20  s.l. All Sky Survey (Röttgering et al. 2008) Ferrari 2008

Hamburg, 18 September 2008 LOFAR Wokshop31/44 30 MHz Resolution ~ 20 arcsec 20  detection - 80% of the radio flux Ferrari 2008 Adapted from Cassano et al Detailed radio/X-ray comparisons Deep Survey sensitivity limits – Röttgering et al. 2008

Hamburg, 18 September 2008 LOFAR Wokshop32/44 30 MHz Resolution ~ 20 arcsec 20  detection - 80% of the radio flux Ferrari 2008 z = 0.1 Adapted from Cassano et al Detailed radio/X-ray comparisons Deep Survey sensitivity limits – Röttgering et al. 2008

Hamburg, 18 September 2008 LOFAR Wokshop33/44 30 MHz Resolution ~ 20 arcsec 20  detection - 80% of the radio flux Ferrari 2008 z = 0.2 Adapted from Cassano et al Detailed radio/X-ray comparisons Deep Survey sensitivity limits – Röttgering et al. 2008

Hamburg, 18 September 2008 LOFAR Wokshop34/44 30 MHz Resolution ~ 20 arcsec 20  detection - 80% of the radio flux Ferrari 2008 z = 0.3 Adapted from Cassano et al Detailed radio/X-ray comparisons Deep Survey sensitivity limits – Röttgering et al. 2008

Hamburg, 18 September 2008 LOFAR Wokshop35/44 30 MHz Resolution ~ 20 arcsec 20  detection - 80% of the radio flux Ferrari 2008 z = 0.4 Adapted from Cassano et al Detailed radio/X-ray comparisons Deep Survey sensitivity limits – Röttgering et al. 2008

Hamburg, 18 September 2008 LOFAR Wokshop36/44 30 MHz Resolution ~ 20 arcsec 20  detection - 80% of the radio flux Ferrari 2008 z = 0.5 Adapted from Cassano et al Detailed radio/X-ray comparisons Deep Survey sensitivity limits – Röttgering et al. 2008

Hamburg, 18 September 2008 LOFAR Wokshop37/44 30 MHz Resolution ~ 20 arcsec 20  detection - 80% of the radio flux Ferrari 2008 z = 0.6 Adapted from Cassano et al Detailed radio/X-ray comparisons Deep Survey sensitivity limits – Röttgering et al. 2008

Hamburg, 18 September 2008 LOFAR Wokshop38/44 30 MHz Resolution ~ 20 arcsec 20  detection - 80% of the radio flux Ferrari 2008 z = 0.8 Adapted from Cassano et al Detailed radio/X-ray comparisons Deep Survey sensitivity limits – Röttgering et al. 2008

Hamburg, 18 September 2008 LOFAR Wokshop39/44 30 MHz Resolution ~ 20 arcsec 20  detection - 80% of the radio flux Ferrari 2008 z = 1.0 Adapted from Cassano et al Detailed radio/X-ray comparisons Deep Survey sensitivity limits – Röttgering et al. 2008

Hamburg, 18 September 2008 LOFAR Wokshop40/44 Detailed radio/X-ray comparisons Adapted from Cassano et al LOFAR estimates: Ferrari 2008 z=0.2 z=0.1 Ferrari 2008 LXLX z 30 MHz Resolution ~ 20 arcsec 20  detection 80% of the radio flux

Hamburg, 18 September 2008 LOFAR Wokshop41/44 Detailed radio/X-ray comparisons Adapted from Cassano et al LOFAR estimates: Ferrari 2008 z=0.2 z=0.1 Ferrari 2008 LXLX z 30 MHz Resolution ~ 20 arcsec 20  detection 80% of the radio flux Simbol-X Spectro-Imager keV ~15“ angular resolution ~12‘ F.o.V.

Hamburg, 18 September 2008 LOFAR Wokshop42/44 Detailed radio/X-ray comparisons Adapted from Cassano et al LOFAR estimates: Ferrari 2008 z=0.2 z=0.1 Ferrari 2008 LXLX z 30 MHz Resolution ~ 20 arcsec 20  detection 80% of the radio flux Brunetti et al. 2007b # clusters with detected HXR F keV = erg cm -2 s -1 5 x erg cm -2 s erg cm -2 s -1 B=0.2  G B=2.0  G Simbol-X limits

Hamburg, 18 September 2008 LOFAR Wokshop43/44 Detailed radio/X-ray comparisons Adapted from Cassano et al LOFAR estimates: Ferrari z  0.2 !!! z=0.2 z=0.1 Ferrari 2008 LXLX z 30 MHz Resolution ~ 20 arcsec 20  detection 80% of the radio flux Arnaud 2008 A2163 (z~0.2) + Simbol-X F.o.V Optimal for the detection of radio relics

Hamburg, 18 September 2008 LOFAR Wokshop44/44 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 + Complementary studies  Statistical studies : e.g. possible comparison with Planck cluster catalogue  Detailed studies : e.g. energetics of the ICM & AGN feedback