Mon. Not. R. Astron. Soc., 425, 162-203 (2012/September-1)
Detailed Sunyaev–Zel'dovich study with AMI of 19 LoCuSS galaxy clusters: masses and temperatures out to the virial radius.
RODRIGUEZ-GONZALVEZ C., SHIMWELL T.W., DAVIES M.L., FEROZ F., FRANZEN T.M.O., GRAINGE K.J.B., HOBSON M.P., HURLEY-WALKER N., LASENBY A.N., OLAMAIE M., POOLEY G., SAUNDERS R.D.E., SCAIFE A.M.M., SCHAMMEL M.P., SCOTT P.F., TITTERINGTON D.J. and WALDRAM E.M.
Abstract (from CDS):
We present detailed 16-GHz interferometric observations using the Arcminute Microkelvin Imager (AMI) of 19 clusters with LX
> 7 x 1037
= 1) selected from the Local Cluster Substructure Survey (LoCuSS; 0.142 ≤ z
≤ 0.295) and of Abell 1758b, which is in the field of view of Abell 1758a. We detect and resolve Sunyaev–Zel'dovich (SZ) signals towards 17 clusters, with peak surface brightnesses between 5σ and 23σ. We use a fast, Bayesian cluster analysis to obtain cluster parameter estimates in the presence of radio point sources, receiver noise and primordial cosmic microwave background (CMB) anisotropy. We fit isothermal β-models to our data and assume the clusters are virialized (with all the kinetic energy in gas internal energy). Our gas temperature, TAMI
, is derived from AMI SZ data and not
from X-ray spectroscopy. Cluster parameters internal to r500
are derived under the assumption of hydrostatic equilibrium. We find the following. (i) Different generalized Navarro–Frenk–White (gNFW) parametrizations yield significantly different parameter degeneracies. (ii) For h70
= 1, we find the classical virial radius, r200
, to be typically 1.6±0.1Mpc and the total mass MT
) typically to be 2.0–2.5 x MT
). (iii) Where we have found MT
) and MT
) X-ray and weak-lensing values in the literature, there is good agreement between weak-lensing and AMI estimates (with \mi M\mi T\mo,\mi AMI
\mo/\mi M\mi T
\mo,\mi WL\mn 1=.\mn 2=–
\mn 0.2 and 1.0±0.1 for r500
, respectively). In comparison, most Suzaku
estimates are higher
than for AMI (with M
_T, AMI_= 1.7±0.2 within r500
), particularly for the stronger mergers. (iv) Comparison of TAMI
sheds light on high X-ray masses: even at large radius, TX
can substantially exceed TAMI
in mergers. The use of these higher TX
values will give higher X-ray masses. We stress that large-radius TAMI
data are scarce and must be increased. (v) Despite the paucity of data, there is an indication of a relation between merger activity and SZ ellipticity. (vi) At small radius (but away from any cooling flow) the SZ signal (and TAMI
) is less sensitive to intracluster medium disturbance than the X-ray signal (and TX
) and, even at high radius, mergers affect n2
-weighted X-ray data more than n
-weighted SZ, implying that significant shocking or clumping or both occur in even the outer parts of mergers.
We request that any reference to this paper cites `AMI Consortium: Rodrìguez-Gonzálvez et al. 2012'.
2012 The Authors Monthly Notices of the Royal Astronomical Society 2012 RAS
methods: observational - techniques: interferometric - galaxies: clusters: general - galaxies: clusters: intracluster medium - cosmic background radiation - large-scale structure of Universe
Table 5: AMI2012d ANNNNa N, AMI2012d RXJHHMM+DDMM N, AMI2012d ZwHHMM.m+DDMM N, N=72.
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