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We present observations between 1.4 and 18 GHz confirming that G64.5+0.9 is new Galactic shell supernova remnant, using the Very Large Array and the Arcminute Microkelvin Imager. The remnant is a shell ~8 arcmin in diameter with a spectral index of alpha = 0.47 +/- 0.03 (with alpha defined such that flux density S varies with frequency nu as S proportional to nu to the power of -alpha). There is also emission near the centre of the shell, ~1 arcmin in extent, with a spectral index of alpha = 0.81 +/- 0.02. We do not find any evidence for spectral breaks for either source within our frequency range. The nature of the central object is unclear and requires further investigation, but we argue that is most unlikely to be extragalactic. It is difficult to avoid the conclusion that it is associated with the shell, although its spectrum is very unlike that of known pulsar wind nebulae., Comment: 5 pages, 6 figures, submitted to MNRAS more...

We present 16-GHz observations using the Arcminute Microkelvin Imager (AMI) of 11 clusters with 7 x 10^{37}W < L_X < 11 x 10^{37}W (h_{50}=1.0) selected from the Local Cluster Substructure Survey (LoCuSS) and compare them to X-ray data. We use a fast, Bayesian cluster analysis to explore the high-dimensional parameter space of the cluster-plus-sources model and obtain robust cluster parameter estimates in the presence of radio point sources, receiver noise and primordial CMB anisotropy. Our analysis fits a spherical, isothermal beta-model to our data and assumes the cluster follows the theoretical mass-temperature relation. Large-scale cluster parameters internal to r_{500} are derived under the assumption of hydrostatic equilibrium. Posterior distributions for the large-scale parameters of 8 of our clusters are given; SZ effects towards Abell 1704 and Zw0857.9+2107 were not detected and our spherical beta-profile was found to be an inadequate fit to the decrement on our map for Abell 2409., 17 pages, 12 figures, 4 tables This paper has been withdrawn by the authors due to major changes more...

We present observations from the Small Array of the Arcminute Microkelvin Imager (AMI) of eight high X-ray luminosity galaxy cluster systems selected from the Local Cluster Substructure Survey (LoCuSS) sample.We detect the Sunyaev-Zel'dovich (SZ) effect in seven of these clusters. With the assumptions that galaxy clusters are isothermal, have a density profile described by a spherical b -model and obey the theoretical M-T relation, we are able to derive cluster parameters at r200 from our SZ data. With the additional assumption of hydrostatic equilibrium we are able to derive parameters at r500. We present posterior probability distributions for cluster parameters such as mass, radius and temperature (TSZ, MT). Combining our sample with that of AMI Consortium: Rodr'\iguez-Gonz\'alvez et al. (2011) and using large-radius X-ray temperature estimates (TX) from Chandra and Suzaku observations, we find that there is reasonable correspondence between TX and TSZ,MT values at low TX, but that for clusters with TX above around 6keV the correspondence breaks down with TX exceeding TSZ, MT; we stress that this finding is based on just ten clusters., Comment: 17 pages, 4 tables, 14 figures more...

The Planck Early Release Compact Source Catalogue includes 26 sources with no obvious matches in other radio catalogues (of primarily extragalactic sources). Here we present observations made with the Arcminute Microkelvin Imager Small Array (AMI SA) at 15.75 GHz of the eight of the unmatched sources at declination > +10 degrees. Of the eight, four are detected and are associated with known objects. The other four are not detected with the AMI SA, and are thought to be spurious., 6 pages, 5 figures, 4 tables more...

We have observed an area of approximatley 27 deg^2 to an rms noise level of less than 0.2 mJy at 15.7 GHz, using the Arcminute Microkelvin Imager Large Array. These observations constitute the most sensitive radio-source survey of any extent (greater than approximately 0.2 deg^2) above 1.4 GHz. This paper presents the techniques employed for observing, mapping and source extraction. We have used a systematic procedure for extracting information and producing source catalogues, from maps with varying noise and uv-coverage. We have performed simulations to test our mapping and source-extraction procedures, and developed methods for identifying extended, overlapping and spurious sources in noisy images. In an accompanying paper, AMI Consortium: Davies et al. 2010, the first results from the 10C survey, including the deep 15.7-GHz source count, are presented., Comment: 9 pages, 11 figures, 4 tables more...

We present observations using the Small Array of the Arcminute Microkelvin Imager (AMI; 14-18 GHz) of four Abell and three MACS clusters spanning 0.171-0.686 in redshift. We detect Sunyaev-Zel'dovich (SZ) signals in five of these without any attempt at source subtraction, although strong source contamination is present. With radio-source measurements from high-resolution observations, and under the assumptions of spherical $\beta$-model, isothermality and hydrostatic equilibrium, a Bayesian analysis of the data in the visibility plane detects extended SZ decrements in all seven clusters over and above receiver noise, radio sources and primary CMB imprints. Bayesian evidence ratios range from 10^{11}:1 to 10^{43}:1 for six of the clusters and 3000:1 for one with substantially less data than the others. We present posterior probability distributions for, e.g., total mass and gas fraction averaged over radii internal to which the mean overdensity is 1000, 500 and 200, r_200 being the virial radius. Reaching r_200 involves some extrapolation for the nearer clusters but not for the more-distant ones. We find that our estimates of gas fraction are low (compared with most in the literature) and decrease with increasing radius. These results appear to be consistent with the notion that gas temperature in fact falls with distance (away from near the cluster centre) out to the virial radius., Comment: 18 pages, 10 figures, submitted to MNRAS (updated authors and fixed Figure 1) more...

Most Sunyaev--Zel'dovich (SZ) and X-ray analyses of galaxy clusters try to constrain the cluster total mass and/or gas mass using parameterised models and assumptions of spherical symmetry and hydrostatic equilibrium. By numerically exploring the probability distributions of the cluster parameters given the simulated interferometric SZ data in the context of Bayesian methods, and assuming a beta-model for the electron number density we investigate the capability of this model and analysis to return the simulated cluster input quantities via three rameterisations. In parameterisation I we assume that the T is an input parameter. We find that parameterisation I can hardly constrain the cluster parameters. We then investigate parameterisations II and III in which fg(r200) replaces temperature as a main variable. In parameterisation II we relate M_T(r200) and T assuming hydrostatic equilibrium. We find that parameterisation II can constrain the cluster physical parameters but the temperature estimate is biased low. In parameterisation III, the virial theorem replaces the hydrostatic equilibrium assumption. We find that parameterisation III results in unbiased estimates of the cluster properties. We generate a second simulated cluster using a generalised NFW (GNFW) pressure profile and analyse it with an entropy based model to take into account the temperature gradient in our analysis and improve the cluster gas density distribution. This model also constrains the cluster physical parameters and the results show a radial decline in the gas temperature as expected. The mean cluster total mass estimates are also within 1 sigma from the simulated cluster true values. However, we find that for at least interferometric SZ analysis in practice at the present time, there is no differences in the AMI visibilities between the two models. This may of course change as the instruments improve., Comment: 19 pages, 13 tables, 24 figures more...