Bibcode
AMI Consortium; Shimwell, T. W.; Barker, R. W.; Biddulph, P.; Bly, D.; Boysen, R. C.; Brown, A. R.; Brown, M. L.; Clementson, C.; Crofts, M.; Culverhouse, T. L.; Czeres, J.; Dace, R. J.; Davies, M. L.; D'Alessandro, R.; Doherty, P.; Duggan, K.; Ely, J. A.; Felvus, M.; Feroz, F.; Flynn, W.; Franzen, T. M. O.; Geisbüsch, J.; Génova-Santos, R.; Grainge, K. J. B.; Grainger, W. F.; Hammett, D.; Hobson, M. P.; Holler, C. M.; Hurley-Walker, N.; Jilley, R.; Kaneko, T.; Kneissl, R.; Lancaster, K.; Lasenby, A. N.; Marshall, P. J.; Newton, F.; Norris, O.; Northrop, I.; Odell, D. M.; Olamaie, M.; Perrott, Y. C.; Pober, J. C.; Pooley, G. G.; Pospieszalski, M. W.; Quy, V.; Rodríguez-Gonzálvez, C.; Saunders, R. D. E.; Scaife, A. M. M.; Schammel, M. P.; Schofield, J.; Scott, P. F.; Shaw, C.; Smith, H.; Titterington, D. J.; Velić, M.; Waldram, E. M.; West, S.; Wood, B. A.; Yassin, G.; Zwart, J. T. L.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 423, Issue 2, pp. 1463-1473.
Advertised on:
6
2012
Citations
12
Refereed citations
10
Description
We present an interesting Sunyaev-Zel’dovich (SZ) detection in the
first of the Arcminute Microkelvin Imager (AMI) ‘blind’,
degree-square fields to have been observed down to our target
sensitivity of ?. In follow-up deep pointed observations the SZ effect
is detected with a maximum peak decrement greater than eight times the
thermal noise. No corresponding emission is visible in the ROSAT all-sky
X-ray survey and no cluster is evident in the Palomar all-sky optical
survey. Compared with existing SZ images of distant clusters, the extent
is large (≈10 arcmin) and complex; our analysis favours a model
containing two clusters rather than a single cluster. Our Bayesian
analysis is currently limited to modelling each cluster with an
ellipsoidal or spherical β model, which does not do justice to this
decrement. Fitting an ellipsoid to the deeper candidate we find the
following. (a) Assuming that the Evrard et al. approximation to Press
& Schechter correctly gives the number density of clusters as a
function of mass and redshift, then, in the search area, the formal
Bayesian probability ratio of the AMI detection of this cluster is 7.9
× 104:1; alternatively assuming Jenkins et al. as the
true prior, the formal Bayesian probability ratio of detection is 2.1
× 105:1. (b) The cluster mass is ?. (c) Abandoning a
physical model with number density prior and instead simply modelling
the SZ decrement using a phenomenological β model of temperature
decrement as a function of angular distance, we find a central SZ
temperature decrement of ?K - this allows for cosmic microwave
background primary anisotropies, receiver noise and radio sources. We
are unsure if the cluster system we observe is a merging system or two
separate clusters. We request that any reference to this paper cites
‘AMI Consortium: Shimwell et al. 2012’.
Related projects
Anisotropy of the Cosmic Microwave Background
The general goal of this project is to determine and characterize the spatial and spectral variations in the temperature and polarisation of the Cosmic Microwave Background in angular scales from several arcminutes to several degrees. The primordial matter density fluctuations which originated the structure in the matter distribution of the present
Rafael
Rebolo López