The XMM Cluster Survey: Optical analysis methodology and the first data release

N. Mehrtens, A. K. Romer, M. Hilton, E. Lloyd-Davies, C. J. Miller, S. A. Stanford, M. Hosmer, B. Hoyle, C. A. Collins, A. R. Liddle, P. T. P. Viana, R. C. Nichol, J. P. Stott, N. Dubois, S. T. Kay, M. Sahlén, O. Young, C. J. Short, L. Christodoulou, W. A. Watson, M. Davidson, C. D. Harrison, L. Baruah, M. Smith, C. Burke, J. A. Mayers, P.-J. Deadman, P. J. Rooney, E. M. Edmondson, M. West, H. Campbell, A. C. Edge, R. G. Mann, K. Sabirli, D. Wake, C. Benoist, L. N. da Costa, M. A. G. Maia, R. L. C. Ogando

Abstract
The XMM Cluster Survey (XCS) is a serendipitous search for galaxy clusters using all publicly available data in the XMM-Newton Science Archive. Its main aims are to measure cosmological parameters and trace the evolution of X-ray scaling relations. In this paper we present the first data release from the XMM Cluster Survey (XCS-DR1). This consists of 503 optically confirmed, serendipitously detected, X-ray clusters. Of these clusters, 255 are new to the literature and 356 are new X-ray discoveries. We present 464 clusters with a redshift estimate (0.06 < z < 1.46), including 261 clusters with spectroscopic redshifts. In addition, we have measured X-ray temperatures (T_X) for 402 clusters (0.4 < T_X < 14.7 keV). We highlight seven interesting subsamples of XCS-DR1 clusters: (i) 10 clusters at high redshift (z > 1:0, including a new spectroscopically-confirmed cluster at z = 1.01); (ii) 67 clusters with high T_X (> 5 keV); (iii) 131 clusters/groups with low T_X (< 2 keV); (iv) 27 clusters with measured T_X values in the SDSS 'Stripe 82' co-add region; (v) 78 clusters with measured T_X values in the Dark Energy Survey region; (vi) 40 clusters detected with sufficient counts to permit mass measurements (under the assumption of hydrostatic equilibrium); (vii) 105 clusters that can be used for applications such as the derivation of cosmological parameters and the measurement of cluster scaling relations. The X-ray analysis methodology used to construct and analyse the XCS-DR1 cluster sample has been presented in a companion paper, Lloyd-Davies et al.

Keywords
X-rays: galaxies: clusters - surveys - galaxies: clusters: individual: (XMMXCS J091821.9+211446.0) - techniques: photometric - techniques: spectroscopic - galaxies: distances and redshifts

Monthly Notices of the Royal Astronomical Society
Volume 423, Page 1024
April 2012

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