Volume 545, September 2012
|Number of page(s)||14|
|Section||Cosmology (including clusters of galaxies)|
|Published online||05 September 2012|
A851 – A851, the lowest redshift cluster in the sample (z = 0.407), has been observed by EPIC XMM-Newton for ~56 ks (ObsID: 0106460101), of which ~41 ks were useful for scientific analysis after removing the periods of high flares. Its temperature profile is quite flat in the central regions with a temperature of ~6 keV, showing a significant decline only in the outer radial bin (r > 700 kpc). As indicated by a value of , this cluster is classified as NCC.
RXCJ0856.1+3756 – RXCJ0856.1+3756 (z = 0.411) has been observed by XMM for ~29 ks (ObsID: 0302581801), with ~24 ks available for our analysis after cleaning the event files from soft proton flares. Although the temperature profile consists of only four radial bins, a hint of a temperature drop in the central bin (r < 170 kpc) is observed, although its value of puts this cluster in the NCC category. The temperature profile then declines from kT ≈ 9 keV down to kT ≈ 5.5 keV) in the outer two bins (r > 250 kpc).
RXJ2228.6+2037 – EPIC XMM-Newton observed the cluster RXJ2228.6+2037 (z = 0.412) for a total of ~26 ks (ObsID: 0147890101), almost entirely useful for our analysis. Although a hint of a drop in the temperature is observed in the central two radial bins (r < 150 kpc), with kT ≈ 8 keV in the central region, this cluster is classified as NCC (). The temperatures reaches its maximum (kT ≈ 9 keV) at r ~ 200 kpc and then declines smoothly down to ~4 keV at radii larger than ~850 kpc.
RXCJ1206.2-0848 – The cluster RXCJ1206.2-0848 (z = 0.440) has been observed twice by EPIC XMM-Newton (ObsIds: 0302581901, 0502430401), but one of the two observation (ObsID: 0302581901) was heavily affected by soft proton flares and was therefore discarded. The ~30 ks of the other observation were almost entirely available for scientific analysis. The temperature profile can be considered approximately constant around kT ≈ 10 keV, although several fluctuations are observed in the profile and the temperature shows a drop of ~3.5 keV between the center and the adjacent radial bin. This cluster is classified as CC, presenting a value of .
IRAS09104+4109 – IRAS09104+4109 (z = 0.442) has been observed by EPIC XMM-Newton for a total of ~14 ks (~12 ks of clean exposure time, ObsID: 0147671001). The temperature shows a hint of a temperature drop in the center (ΔkT ~ 0.5 keV), and decreases from ~6.5 keV to ~4.5 keV between the region located at ~100 kpc from the center and the one located at ~200 kpc, remaining constant around the latter value going toward larger radii. This cluster shows a value of and is therefore classified as NCC.
RXJ1347.5-1145 – RXJ1347.5-1145 (z = 0.451), representing the brightest cluster in our sample with its X-ray luminosity of 4.2 × 1045 erg s-1 (0.1–2.4 keV band, Ebeling et al. 2010), has been observed for ~38 ks (~32 ksec after cleaning for flares) by XMM-Newton (ObsID: 0112960101). This cluster shows evidence of a very strong cool core with the temperature dropping from kT ≈ 13.5 keV to kT ≈ 10 keV in the central bin (r < 90 kpc) and is classified as a CC cluster (, the lowest value among the clusters in our sample). Although some irregularities in the profile are present, the temperature
then declines smoothly toward the outer regions, reaching a value around ~6 keV at r > 750 kpc.
CLJ0030+2618 – The cluster CLJ0030+2618 (z = 0.500) has been observed three times by XMM-Newton (ObsIds: 0302581101, 0402750201, 0402750601) for a total of ~94 ks, of which ~70 ks were available after removing the high-flaring intervals. The number of counts available did not allow us to divide the emission into more than three radial bins, with the temperature profiles being approximately constant around ~5 keV. CLJ0030+2618 is classified as a NCC cluster, as indicated by a .
MS0015.9+1609 – MS0015.9+1609 (z = 0.541) has been observed twice by XMM (ObsIds: 0111000101, 0111000201) for a total of ~45 ks (~36 ks of clean exposure time). The temperature profile declines smoothly from kT ≈ 12 keV measured at the center down to a minimum of ~7 keV observed as far as ~900 kpc from the center, making of it a clear example of a NCC cluster ().
MS0451.6-0305 – The galaxy cluster MS0451.6-0305 (z = 0.550) has been observed by XMM-Newton (ObsId: 0205670101) for a total of ~45 ks. The observation was heavily affected by soft proton flares and we were able to use only ~26 ks of the original exposure. The observed temperature shows a drop in the central 200 kpc (kT ~ 9 keV) and is then quite constant around ~11 keV between 200 and 450 kpc. It then declines to ~6 keV at r > 450 kpc. The value of measured for this cluster puts it in the CC category.
MACSJ0647.7+7015 – EPIC XMM-Newton observed twice (ObsIDs: 0551850401, 0551851301) the galaxy cluster MACSJ0647.7+7015 (z = 0.591) for a total of ~145 ks (~88 keV of clean exposure time). The temperature observed in this cluster shows a smooth decline from the center (kT ≈ 12 keV) toward the outskirts (kT ≈ 6−7 keV at r > 450 kpc), making of it another obvious example of NCC cluster ().
MACSJ0744.9+3927 – Two EPIC observations of the cluster of galaxy MACSJ0744.9+3927 (z = 0.698) are present in the XMM-Newton archive (ObsIDs: 0551850101, 0551851201) accounting for a total exposure time of ~154 ks (~106 ks after cleaning for high-flaring periods). MACSJ0744.9+3927 is another examples of strong CC present in our sample (as indicated also by ), showing a temperature drop from ~10 keV (at ~150 kpc from the center) to ~7.5 keV in the central radial bin (r < 100 kpc). The temperature smoothly declines toward the outskirts and stabilizes around a value of ~6 keV at r > 500 kpc.
CLJ1226.9+3332 – CLJ1226.9+3332, the farthest cluster in our sample (z = 0.890), has been observed twice by EPIC XMM-Newton (ObsIds: 0070340501, 0200340101) for a total of ~139 ks. Both observation were heavily affected by soft proton flares (in particular ~75% of ObsID 0070340501 was affected by soft protons), leaving just ~77 ks of clean exposure time available for scientific analysis. The temperature shows a sharp decline from the center (kT ≈ 13 keV) toward the outer radial bin as far as ~500 kpc from the core (kT ≈ 6 keV). This cluster is classified as a NCC ().
© ESO, 2012
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