High-z clusters: prospectives with SKA and its precursors Chiara Ferrari (OCA, Lagrange) Image courtesy: www.skatelescope.org
SKA1: 2018-2023 with cost-cap 650 M € SKA1-LOW (AUS) SKA1-MID (SA) • 130,000 dipoles • 133 15m dishes + MeerKAT • Frequency coverage: 50 - 350 MHz • Frequency coverage: 0.350 - 1.8 GHz & 4.6 - 13.8 GHz • Max baseline: 80 km • Max baseline: 150 km
The precursors • Location: South Africa • Max baseline: 8 km • Frequency coverage: 0.5 - 10 GHz MeerKAT • Number of antennas: 64 • Diameter of antennas: 13.5 m • Fully operational from 2017 • Location: Australia • Max baseline: 6 km • Frequency coverage: 0.7 - 8 GHz ASKAP • Number of antennas: 36 • Diameter of antennas: 12 m • Fully operational from 2016 • Location: Australia • Max baseline: 3 km • Frequency coverage: 80 - 300 MHz MWA • Number of stations: 128 • Antennas per station: 16 • Fully operational since 2012
Importance of radio observations for high-z cluster studies Castignani+ 14 40.0 Gitti+ 15 35.0 Detection of high-z clusters 30.0 25.0 FRI / FRII 20.0 Di ff use radio emission 15.0 10.0 ICM physics 05.0 Miley+ 06 76:23:00.0 50 kpc Feedback 55.0 20.0 18.0 16.0 14.0 12.0 9:47:10.0 08.0 06.0 04.0 Non-thermal component Galaxy evolution
Importance of radio observations for high-z cluster studies Castignani+ 14 Detection of high-z clusters FRI / FRII Di ff use radio emission ICM physics Feedback Non-thermal component Galaxy evolution
Detection of high-z clusters - FRI and FRII as beacons - FRII: FRI: ~20-25% in ~70% in intermediate/ clusters rich groups (from low to (low-z) high-z) ~20-50% (high-z) e.g. Zirbel 97; e.g. Zirbel 97; Galametz+12 Castignani+14
Detection of high-z clusters - FRI and FRII as beacons - FRII: FRI: MP J1758 − 6738: z=2.026 ~20-25% in ~70% in 10 intermediate/ clusters 5 rich groups (from low to Arcminutes NVSS J111921 − 363139: z=2.769 10 0 (low-z) high-z) 5 ~20-50% − 5 Arcminutes (high-z) 0 − 10 − 10 − 5 0 5 10 Arcminutes − 5 e.g. Zirbel 97; e.g. Zirbel 97; Rigby+ 14 Galametz+12 Castignani+14 − 10 − 10 − 5 0 5 10 Arcminutes
Detection of high-z clusters - FRI and FRII as beacons - FRII: FRI: MP J1758 − 6738: z=2.026 ~20-25% in ~70% in 10 z~0.9-2.9 intermediate/ clusters 5 rich groups (from low to Arcminutes NVSS J111921 − 363139: z=2.769 10 0 (low-z) high-z) 5 ~20-50% − 5 Arcminutes (high-z) 0 − 10 − 10 − 5 0 5 10 Arcminutes − 5 e.g. Zirbel 97; e.g. Zirbel 97; Rigby+ 14 Castignani+ 14 Galametz+12 Castignani+14 − 10 − 10 − 5 0 5 10 Arcminutes
Summary plot for radio surveys Bulk of AGN population down to L~10 22 W/Hz , z~0.5 (Wide), z~2 (Deep), z~4 (Ultra Deep) 0.5'' resolution at ~1 GHz Prandoni & Seymour 15
Summary plot for radio surveys Bulk of AGN population down to L~10 22 W/Hz , z~0.5 (Wide), Pre-SKA z~2 (Deep), z~4 (Ultra Deep) SKA 0.5'' resolution at ~1 GHz Pre-2010 Prandoni & Seymour 15
SKA survey speed SKA1 Science Requirements Braun+ (SKAO)
Polarisation studies B · d � n e � � RM ∝ l χ = χ 0 + RM × λ 2 Coma-like cluster 400 Bonafede+ 15 VLA observations 300 SKA1-SUR 2 |RM| rad/m 200 100 0 200 400 600 800 1000 1200 distance [kpc] Figure 1: SKA1-SUR predictions for the RM for Coma-lik
Polarisation studies Broderick+ 07 B · d � n e � � RM ∝ l χ = χ 0 + RM × λ 2 Coma-like cluster 400 Bonafede+ 15 VLA observations 300 SKA1-SUR 2 |RM| rad/m 200 100 0 200 400 600 800 1000 1200 distance [kpc] Figure 1: SKA1-SUR predictions for the RM for Coma-lik
Polarisation studies Broderick+ 07 B · d � n e � � RM ∝ l Fabian & Sanders 09 Taylor+ 01
Diffuse radio emission in clusters Correlation between X-ray and radio The Coma cluster observed at 352 MHz with WSRT cluster luminosities Brown & Rudnick 11 Cassano+ 13
Detection of clusters through their diffuse radio emission X-ray images 1 Mpc MACSJ0520.7-1328 Radio contours 1WGA J0521.0-1333 Companion of MACS J0520.7-1328 Companion of A3527 (z=0.3) (z=0.2) Macario+ 14 de Gasperin+ 16
Detection of diffuse radio emission at high-z : a challenging task Radio image at 25 cm of A2255 Pizzo & de Bruyn 09
Diffuse radio emission from galaxy clusters with SKA1 Radio galaxies + Cassano+ 13 Radio halo (P 1.4 GHz ~ 1 × 10 24 W/Hz) @ z ≥ 0.5 Relativistic electron population + Magnetic field model Faraday tool (Murgia+ 04) Feretti+ 12
Diffuse radio emission from galaxy clusters with SKA1 Radio galaxies + 8 hours observations Radio halo (P 1.4 GHz ~ 1 × 10 24 W/Hz) 60 sec integration time @ z ≥ 0.5 50 MHz BW starting @ 1415 MHz Relativistic electron population Simulations of SKA1 MID & SUR + Magnetic field model observations Faraday tool (Murgia+ 04) MeqTrees tool (Noordam & Smirnov 10)
Simulated SKA1-MID observations SKA1 MID (Zoom in) Radio maps before deconvolution from the instrument PSF 1 arcsec resolution Ferrari+ 15 MORESANE algorithm : new deconvolution method based on sparse representations developed @ OCA, Nice (FR) Dabbech+ 12; Dabbech+ 15
Up to which z can we detect this cluster with SKA1 MID? z=0.5 Res ~ 1” MORESANE MORESANE MS-CLEAN MS-CLEAN Simulated cluster source model residuals source model residuals z=1.0 16 Res ~ 1”
Intra-cluster primary cosmic rays Primary cosmic rays protons (CRPs) & electrons (CREs)
Intra-cluster primary cosmic rays Primary cosmic rays protons (CRPs) & electrons (CREs) External processes CRs acceleration driven by the assembly of clusters - accretion shocks ( M ~ 10 3 ) - merging shocks ( M ~ 3-10) - ICM turbulence Courtesy: Vazza
Intra-cluster primary cosmic rays Primary cosmic rays protons (CRPs) & electrons (CREs) Internal processes External processes CRs accelerated inside cluster galaxies and CRs acceleration driven by the assembly of clusters then injected - accretion shocks ( M ~ 10 3 ) - SN ae driven galactic winds - merging shocks ( M ~ 3-10) - AGNs - ICM turbulence Courtesy: Koekemoer Shull 09 Courtesy: Vazza
Not only non-thermal emission with SKA ‐ Sky Noise: 350 MHz to 25 GHz & SKA1 ‐ mid Receiver Bands 50 45 40 35 Band 5+ 30 log Tb (K) Band 4 25 20 Band 3 15 Band 2 10 5 SKA1 ‐ mid Band 1 0 100 1000 10000 log (f) MHz ‐ ‐ SKA1 Baseline Designe Simulated 1h observation with SKA1-MID ‐ SKAO (Band 5) ‐ ‐ ‐ SZ signal from a cluster with ‐ M 200 = 4x10 14 M Sun at z=1.83 ‐ Grainge+ 15 ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐
Importance of radio observations for high-z cluster studies 40.0 Gitti+ 15 35.0 Detection of high-z clusters 30.0 FRI / FRII 25.0 Di ff use radio emission 20.0 ICM physics 15.0 10.0 Feedback 05.0 Non-thermal component 76:23:00.0 50 kpc Galaxy evolution 55.0 20.0 18.0 16.0 14.0 12.0 9:47:10.0 08.0 06.0 04.0
Radio feedback in cool-core clusters FRI radio galaxies in ≿ 70% of cD galaxies of cool-core clusters Bubbles of relativistic plasma excavating cavities in the ICM distribution Radio X-rays McNamara+ 09
Radio feedback in cool-core clusters at high-z Santos+ 10 NVSS limit @ z=1 Chandra image + Residual Chandra VLA image WARPJ1415.1+3612 VLA contours image at z =1 Santos+ 12
Radio feedback in cool-core clusters at high-z Gitti+ 15 Santos+ 10 Chandra image + Residual Chandra VLA image WARPJ1415.1+3612 VLA contours image at z =1 Santos+ 12
the galaxy cluster radio “zoo” Radio halo Several Mpc Feretti+ 01 Feretti+ 01 Mini-halo Scale Few hundreds kpc 20 kpc M87 Ferrari+ 11 Several tens kpc de Gasperin+ 12
A global view of non-thermal emission and feedback activity 40.0 35.0 30.0 25.0 20.0 15.0 10.0 05.0 76:23:00.0 50 kpc 55.0 20.0 18.0 16.0 14.0 12.0 9:47:10.0 08.0 06.0 04.0 Gitti+ 15
Importance of radio observations for high-z cluster studies Miley+ 06 Detection of high-z clusters FRI / FRII Di ff use radio emission ICM physics Feedback Non-thermal component Galaxy evolution
Nuclear and star-formation activity in high-z cluster galaxies b Wang+ 16
Nuclear and star-formation activity in high-z cluster galaxies b Murphy+ 15 Wang+ 16
Nuclear and star-formation activity in high-z cluster galaxies b z=2 for ν obs =10 GHz Murphy+ 15 Murphy+ 15 Wang+ 16
The SKA will be an important instrument for the identification and physical characterisation of high-z clusters Detection of high-z clusters FRI / FRII Di ff use radio emission Thanks! ICM physics Feedback Non-thermal component Galaxy evolution
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