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The Arcminute Microkelvin Imager (AMI) Galactic Plane Survey is a large-area survey of the outer Galactic plane to provide arcminute resolution images at milli-Jansky sensitivity in the centimetre-wave band. Here we present the first data release of the survey, consisting of 868 deg2 of the Galactic plane, covering the area 76° $\lessapprox $ ℓ $\lessapprox $ 170° between latitudes of |b| $\lessapprox $ 5°, at a central frequency of 15.75 GHz (1.9 cm). We describe in detail the drift-scan observations which have been used to construct the maps, including the techniques used for observing, mapping and source extraction, and summarize the properties of the finalized data sets. These observations constitute the most sensitive Galactic plane survey of large extent at centimetre-wave frequencies greater than 1.4 GHz. [ABSTRACT FROM AUTHOR]

ABSTRACT We present detailed 16-GHz interferometric observations using the Arcminute Microkelvin Imager (AMI) of 19 clusters with LX > 7 × 1037 W ( h50 = 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 ± 0.1 Mpc and the total mass MT( r200) typically to be 2.0-2.5× MT( r500). (iii) Where we have found MT( r500) and MT( r200) X-ray and weak-lensing values in the literature, there is good agreement between weak-lensing and AMI estimates (with [ABSTRACT FROM AUTHOR]

ABSTRACT Most Sunyaev-Zel'dovich (SZ) and X-ray analyses of galaxy clusters try to constrain the cluster total mass ( MT( r)) and/or gas mass ( Mg( r)) using parametrized models derived from both simulations and imaging observations, 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 β-model for the electron number density ne( r) described by two shape parameters β and rc, we investigate the capability of this model and analysis to return the simulated cluster input quantities via three parametrizations. In parametrization I we assume that the gas temperature is an independent free parameter and assume hydrostatic equilibrium, spherical geometry and an ideal gas equation of state. We find that parametrization I can hardly constrain the cluster parameters and fails to recover the true values of the simulated cluster. In particular it overestimates MT( r200) and Tg( r200) ( MT( r200) = (6.43 ± 5.43) × 1015 M⊙ and Tg( r200) = (10.61 ± 5.28) keV) compared to the corresponding values of the simulated cluster ( MT( r200) = 5.83 × 1014 M⊙ and Tg( r200) = 5 keV). We then investigate parametrizations II and III in which fg( r200) replaces temperature as a main variable; we do this because fg may vary significantly less from cluster to cluster than temperature. In parametrization II we relate MT( r200) and Tg assuming hydrostatic equilibrium. We find that parametrization II can constrain the cluster physical parameters but the temperature estimate is biased low ( MT( r200) = (6.8 ± 2.1) × 1014 M⊙ and Tg( r200) = (3.0 ± 1.2) keV). In parametrization III, the virial theorem (plus the assumption that all the kinetic energy of the cluster is the internal energy of the gas) replaces the hydrostatic equilibrium assumption because we consider it more robust both in theory and in practice. We find that parametrization III results in unbiased estimates of the cluster properties ( MT( r200) = (4.68 ± 1.56) × 1014 M⊙ and Tg( r200) = (4.3 ± 0.9) keV). We generate a second simulated cluster using a generalized Navarro-Frenk-White 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 1σ from the simulated cluster true values: MT( r200) = (5.9 ± 3.4) × 1014 M⊙ and Tg( r200) = (7.4 ± 2.6) keV using parametrization II, and MT( r200) = (8.0 ± 5.6) × 1014 M⊙ and Tg( r200) = (5.98 ± 2.43) keV using parametrization III. However, we find that for at least interferometric SZ analysis in practice at the present time, there is no differences in the Arcminute Microkelvin Imager (AMI) visibilities between the two models. This may of course change as the instruments improve. [ABSTRACT FROM AUTHOR]

ABSTRACT The Planck Early Release Compact Source Catalogue includes 26 sources with no obvious matches in other radio catalogues (of predominantly extragalactic sources). Here we present observations made with the Arcminute Microkelvin Imager Small Array (AMI SA) at 15.75 GHz of the eight unmatched sources at δ > +10°. 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. [ABSTRACT FROM AUTHOR]

ABSTRACT We present an analysis of observations made with the Arcminute Microkelvin Imager (AMI) and the Canada-France-Hawaii Telescope (CFHT) of six galaxy clusters in a redshift range of 0.16-0.41. The cluster gas is modelled using the Sunyaev-Zel'dovich (SZ) data provided by AMI, while the total mass is modelled using the lensing data from the CFHT. In this paper, we (i) find very good agreement between SZ measurements (assuming large-scale virialization and a gas-fraction prior) and lensing measurements of the total cluster masses out to r200; (ii) perform the first multiple-component weak-lensing analysis of A115; (iii) confirm the unusual separation between the gas and mass components in A1914 and (iv) jointly analyse the SZ and lensing data for the relaxed cluster A611, confirming our use of a simulation-derived mass-temperature relation for parametrizing measurements of the SZ effect. [ABSTRACT FROM AUTHOR]

ABSTRACT 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 β-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 cosmic microwave background imprints. Formal Bayesian evidence ratios range from 1011:1 to 1043:1 for six of the clusters and 3000:1 for one with substantially fewer 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, r200 being the virial radius. Reaching r200 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. [ABSTRACT FROM AUTHOR]

ABSTRACT We have observed an area of ≈27 deg2 to an rms noise level of 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 (≳0.2 deg2) 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 u v-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., the first results from the 10C survey, including the deep 15.7-GHz source count, are presented. [ABSTRACT FROM AUTHOR]

ABSTRACT In a previous paper (Paper I), the observational, mapping and source-extraction techniques used for the Tenth Cambridge (10C) Survey of Radio Sources were described. Here, the first results from the survey, carried out using the Arcminute Microkelvin Imager Large Array (LA) at an observing frequency of 15.7 GHz, are presented. The survey fields cover an area of ≈27 deg2 to a flux-density completeness of 1 mJy. Results for some deeper areas, covering ≈12 deg2, wholly contained within the total areas and complete to 0.5 mJy, are also presented. The completeness for both areas is estimated to be at least 93 per cent. The 10C survey is the deepest radio survey of any significant extent (≳0.2 deg2) above 1.4 GHz. The 10C source catalogue contains 1897 entries and is available online. The source catalogue has been combined with that of the Ninth Cambridge Survey to calculate the 15.7-GHz source counts. A broken power law is found to provide a good parametrization of the differential count between 0.5 mJy and 1 Jy. The measured source count has been compared with that predicted by de Zotti et al. - the model is found to display good agreement with the data at the highest flux densities. However, over the entire flux-density range of the measured count (0.5 mJy to 1 Jy), the model is found to underpredict the integrated count by ≈30 per cent. Entries from the source catalogue have been matched with those contained in the catalogues of the NRAO VLA Sky Survey and the Faint Images of the Radio Sky at Twenty-cm survey (both of which have observing frequencies of 1.4 GHz). This matching provides evidence for a shift in the typical 1.4-GHz spectral index to 15.7-GHz spectral index of the 15.7-GHz-selected source population with decreasing flux density towards sub-mJy levels - the spectra tend to become less steep. Automated methods for detecting extended sources, developed in Paper I, have been applied to the data; ≈5 per cent of the sources are found to be extended relative to the LA-synthesized beam of ≈30 arcsec. Investigations using higher resolution data showed that most of the genuinely extended sources at 15.7 GHz are classical doubles, although some nearby galaxies and twin-jet sources were also identified. [ABSTRACT FROM AUTHOR]

We present follow-up observations of two galaxy clusters detected blindly via the Sunyaev-Zel'dovich (SZ) effect and released in the Planck Early Release Compact Source Catalogue. We use the Arcminute Microkelvin Imager, a dual-array 14-18 GHz radio interferometer. After radio source subtraction, we find a SZ decrement of integrated flux density −1.08 ± 0.10 mJy towards PLCKESZ G121.11+57.01, and improve the position measurement of the cluster, finding the centre to be RA , to an accuracy of 20 arcsec. The region of PLCKESZ G115.71+17.52 contains strong extended emission, so we are unable to confirm the presence of this cluster via the SZ effect. [ABSTRACT FROM AUTHOR]

Observations at 14.2 to 17.9 GHz made with the Arcminute Microkelvin Imager (AMI) Small Array towards 14 Lynds dark nebulae with a resolution of ≈2 arcmin are reported. These sources are selected from the Submillimetre Common-User Bolometre Array (SCUBA) observations of Visser, Richer & Chandler as small angular diameter clouds well matched to the synthesized beam of the AMI Small Array. Comparison of the AMI observations with radio observations at lower frequencies with matched uv-plane coverage is made, in order to search for any anomalous excess emission which can be attributed to spinning dust. Possible emission from spinning dust is identified as a source within a 2-arcmin radius of the SCUBA position of the Lynds dark nebula, exhibiting an excess with respect to lower frequency radio emission. We find five sources which show a possible spinning dust component in their spectra. These sources have rising spectral indices in the frequency range 14.2–17.9 GHz with to , where . Of these five one has already been reported, L1111, we report one new definite detection, L675 (16σ), and three new probable detections (L944, L1103 and L1246). The relative certainty of these detections is assessed on the basis of three criteria: the extent of the emission, the coincidence of the emission with the SCUBA position and the likelihood of alternative explanations for the excess. Extended microwave emission makes the likelihood of the anomalous emission arising as a consequence of a radio counterpart to a protostar or a protoplanetary disc unlikely. We use a 2-arcmin radius in order to be consistent with the IRAS identifications of dark nebulae, and our third criterion is used in the case of L1103 where a high flux density at 850 μm relative to the far-infrared data suggests a more complicated emission spectrum. [ABSTRACT FROM AUTHOR]

We present observations between 14.2 and 17.9 GHz of 12 reported supernova remnants (SNRs) made with the Arcminute Microkelvin Imager Small Array (AMI SA). In conjunction with data from the literature at lower radio frequencies, we determine spectra of these objects. For well-studied SNRs (Cas A, Tycho's SNR, 3C 58 and the Crab Nebula), the results are in good agreement with spectra based on previous results. For the less well-studied remnants, the AMI SA observations provide higher-frequency radio observations than previously available, and better constrain their radio spectra. The AMI SA results confirm a spectral turnover at ≃11 GHz for the filled-centre remnant G74.9+1.2. We also see a possible steepening of the spectrum of the filled-centre remnant G54.1+0.3 within the AMI SA frequency band compared with lower frequencies. We confirm that G84.9+0.5, which had previously been identified as a SNR, is rather an H ii region and has a flat radio spectrum. [ABSTRACT FROM AUTHOR]

ABSTRACT Most Sunyaev-Zel'dovich (SZ) and X-ray analyses of galaxy clusters try to constrain the cluster total mass ( MT( r)) and/or gas mass ( Mg( r)) using parametrized models derived from both simulations and imaging observations, 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 β-model for the electron number density ne( r) described by two shape parameters β and rc, we investigate the capability of this model and analysis to return the simulated cluster input quantities via three parametrizations. In parametrization I we assume that the gas temperature is an independent free parameter and assume hydrostatic equilibrium, spherical geometry and an ideal gas equation of state. We find that parametrization I can hardly constrain the cluster parameters and fails to recover the true values of the simulated cluster. In particular it overestimates MT( r200) and Tg( r200) ( MT( r200) = (6.43 ± 5.43) × 1015 M⊙ and Tg( r200) = (10.61 ± 5.28) keV) compared to the corresponding values of the simulated cluster ( MT( r200) = 5.83 × 1014 M⊙ and Tg( r200) = 5 keV). We then investigate parametrizations II and III in which fg( r200) replaces temperature as a main variable; we do this because fg may vary significantly less from cluster to cluster than temperature. In parametrization II we relate MT( r200) and Tg assuming hydrostatic equilibrium. We find that parametrization II can constrain the cluster physical parameters but the temperature estimate is biased low ( MT( r200) = (6.8 ± 2.1) × 1014 M⊙ and Tg( r200) = (3.0 ± 1.2) keV). In parametrization III, the virial theorem (plus the assumption that all the kinetic energy of the cluster is the internal energy of the gas) replaces the hydrostatic equilibrium assumption because we consider it more robust both in theory and in practice. We find that parametrization III results in unbiased estimates of the cluster properties ( MT( r200) = (4.68 ± 1.56) × 1014 M⊙ and Tg( r200) = (4.3 ± 0.9) keV). We generate a second simulated cluster using a generalized Navarro-Frenk-White 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 1σ from the simulated cluster true values: MT( r200) = (5.9 ± 3.4) × 1014 M⊙ and Tg( r200) = (7.4 ± 2.6) keV using parametrization II, and MT( r200) = (8.0 ± 5.6) × 1014 M⊙ and Tg( r200) = (5.98 ± 2.43) keV using parametrization III. However, we find that for at least interferometric SZ analysis in practice at the present time, there is no differences in the Arcminute Microkelvin Imager (AMI) visibilities between the two models. This may of course change as the instruments improve. [ABSTRACT FROM AUTHOR]

ABSTRACT The Planck Early Release Compact Source Catalogue includes 26 sources with no obvious matches in other radio catalogues (of predominantly extragalactic sources). Here we present observations made with the Arcminute Microkelvin Imager Small Array (AMI SA) at 15.75 GHz of the eight unmatched sources at δ > +10°. 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. [ABSTRACT FROM AUTHOR]