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5 results on '"Elizabeth Waldram"'

1. AMI-CL J0300+2613: a Galactic anomalous-microwave-emission ring masquerading as a galaxy cluster

Author

Clare Rumsey, Nima Razavi-Ghods, Keith Grainge, Anna M. M. Scaife, T. M. Cantwell, Patrick J. Elwood, Richard D. E. Saunders, Kamran Javid, Terry Z. Jin, David Titterington, Michael P. Hobson, Guy G. Pooley, Yvette C. Perrott, Farhan Feroz, Timothy W. Shimwell, David A. Green, Paul F. Scott, Elizabeth Waldram, Michel P. Schammel, S. H. Carey, Perrott, Yvette Chanel [0000-0002-6255-8240], Green, David [0000-0003-3189-9998], Javid, Kamran [0000-0002-2089-3964], Razavi-Ghods, Nima [0000-0003-2930-5396], Saunders, Richard [0000-0003-3167-5863], Titterington, David [0000-0003-1431-920X], and Apollo - University of Cambridge Repository

Subjects
Arcminute Microkelvin Imager, Extinction (astronomy), FOS: Physical sciences, Astrophysics, Ring (chemistry), 01 natural sciences, clusters: individual: AMI-CL J0300+2613 [Galaxies], 0103 physical sciences, 010303 astronomy & astrophysics, Dust, extinction, Galaxy cluster, High dynamic range, infrared: ISM, Physics, Completely blind, 010308 nuclear & particles physics, ISM [infrared], Astronomy, Astronomy and Astrophysics, Type-cD galaxy, ISM [Radio continuum], Astrophysics - Astrophysics of Galaxies, galaxies: clusters: individual: AMI-CL J0300+2613, radio continuum: ISM, Microwave emission, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), dust, extinction
Abstract

The Arcminute Microkelvin Imager (AMI) carried out a blind survey for galaxy clusters via their Sunyaev-Zel'dovich effect decrements between 2008 and 2011. The first detection, known as AMI-CL J0300+2613, has been reobserved with AMI equipped with a new digital correlator with high dynamic range. The combination of the new AMI data and more recent high-resolution sub-mm and infra-red maps now shows the feature in fact to be a ring of positive dust-correlated Galactic emission, which is likely to be anomalous microwave emission (AME). If so, this is the first completely blind detection of AME at arcminute scales., 11 pages, 13 figures, 4 tables. Submitted to MNRAS

Published
2017
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2. The radio source population at high frequency: follow-up of the 15-GHz 9C survey

Author

Anthony C. S. Readhead, Claire J. Chandler, Guy G. Pooley, Elizabeth Waldram, Brian Mason, T. J. Pearson, Garret Cotter, R. C. Bolton, and Julia M. Riley

Subjects
Physics, Space and Planetary Science, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Radio spectrum, Spectral line, Source Population
Abstract

We have carried out extensive radio and optical follow-up of 176 sources from the 15 GHz 9th Cambridge survey. Optical identifications have been found for 155 of the radio sources; optical images are given with radio maps overlaid. The continuum radio spectrum of each source spanning the frequency range 1.4 - 43 GHz is also given. Two flux-limited samples are defined, one containing 124 sources complete to 25 mJy and one of 70 sources complete to 60 mJy. Between one fifth and one quarter of sources from these flux-limited samples display convex radio spectra, rising between 1.4 and 4.8 GHz. These rising-spectrum sources make up a much larger fraction of the radio source population at this high selection frequency than in lower frequency surveys. We find that by using non-simultaneous survey flux density measurements at 1.4 and 15 GHz to remove steep spectrum objects, the efficiency of selecting objects with spectra rising between 1.4 and 4.8 GHz (as seen in simultaneous measurements) can be raised to 49 percent without compromising the completeness of the rising spectrum sample., Comment: 40 pages, 223 figures. Accepted for publication in MNRAS. Version with full size images (A4 paper) avaliable at http://www.mrao.cam.ac.uk/publications/papers files ME777.ps and ME777.pdf

Published
2016
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3. Quasars from the 7C Survey - I:sample selection and radio maps

Author

Philip Miller, Julia M. Riley, Katherine M. Blundell, Elizabeth Waldram, Richard G. McMahon, Steve Rawlings, and Mark Lacy

Subjects
Physics, Sample selection, media_common.quotation_subject, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Quasar, Astrophysics, Approx, Space and Planetary Science, Sky, Magnitude (astronomy), media_common
Abstract

We describe the selection of candidate radio-loud quasars obtained by cross-matching radio source positions from the low-frequency (151 MHz) 7C survey with optical positions from five pairs of EO POSS-I plates scanned with the Cambridge Automatic Plate-measuring Machine (APM). The sky region studied is centred at RA 10 h 28 m, Dec +41 and covers 0.057 sr. We present VLA observations of the quasar candidates, and tabulate various properties derived from the radio maps. We discuss the selection criteria of the resulting `7CQ' sample of radio-loud quasars. The 70 confirmed quasars, and some fraction of the 36 unconfirmed candidates, constitute a filtered sample with the following selection criteria: 151-MHz flux density S151 > 100 mJy; POSS-I E-plate magnitude E approx R < 20; and POSS-I colour (O - E) < 1.8; the effective area of the survey drops significantly below S151 approx 200 mJy. We argue that the colour criterion excludes few if any quasars, but note, on the basis of recent work by Willott et al. (1998b), that the E magnitude limit probably excludes more than 50 per cent of the radio-loud quasars., Latex, 30 pages. Accepted by MNRAS

Published
2016

4. Estimating the bispectrum of the Very Small Array data

Author

Anthony Lasenby, Rod D. Davies, Pedro Carreira, Rafael Rebolo, David Titterington, Pedro Sosa Molina, Sarah Smith, Carlos M. Gutiérrez, Paul F. Scott, Clive Dickinson, Ricardo Genova-Santos, Keith Grainge, Katy Lancaster, Graca Rocha, Richard S. Savage, Kieran Cleary, J. P. Leahy, Yaser A. Hafez, Rüdiger Kneissl, Nutan Rajguru, Richard A. Battye, Anže Slosar, Robert A. Watson, Richard D. E. Saunders, Angela C. Taylor, Jose Alberto Rubino-Martin, Michael P. Hobson, Anthony Challinor, Elizabeth Waldram, M. Jones, Richard J. Davis, Klaus Maisinger, and Guy G. Pooley

Subjects
Physics, Gaussian, Astrophysics (astro-ph), Estimator, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Residual, symbols.namesake, Space and Planetary Science, Coupling parameter, Very Small Array, symbols, Point (geometry), Limit (mathematics), Statistical physics, Bispectrum
Abstract

We estimate the bispectrum of the Very Small Array data from the compact and extended configuration observations released in December 2002, and compare our results to those obtained from Gaussian simulations. There is a slight excess of large bispectrum values for two individual fields, but this does not appear when the fields are combined. Given our expected level of residual point sources, we do not expect these to be the source of the discrepancy. Using the compact configuration data, we put an upper limit of 5400 on the value of f_NL, the non-linear coupling parameter, at 95 per cent confidence. We test our bispectrum estimator using non-Gaussian simulations with a known bispectrum, and recover the input values., Comment: 17 pages, 16 figures, replaced with version accepted by MNRAS. Primordial bispectrum recalculated and figure 11 changed

Published
2016
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5. Comparison of Sunyaev-Zel'dovich measurements from Planck and from the Arcminute Microkelvin Imager for 99 galaxy clusters

Author

G. Chon, J. Démoclès, Elizabeth Waldram, Yvette C. Perrott, R. A. Burenin, Anthony Lasenby, R. Barrena, Michel P. Schammel, Herve Aussel, Jose Alberto Rubino-Martin, Michael L. Brown, Debbie Harrison, Guy G. Pooley, G. W. Pratt, Monique Arnaud, I. F. Bikmaev, Michael P. Hobson, Nabila Aghanim, Timothy W. Shimwell, J. F. Macías-Pérez, C. J. MacTavish, Irek Khamitov, Farhan Feroz, Barbara Comis, G. Hurier, Paul F. Scott, A. Hempel, Marian Douspis, R. Kneissl, D. Sutton, Hans Böhringer, David Titterington, P. Carvalho, Keith Grainge, V. Stolyarov, Håkon Dahle, J. B. Melin, Malak Olamaie, Richard D. E. Saunders, Clare Rumsey, Etienne Pointecouteau, M. A. J. Ashdown, Cavendish Laboratory, University of Cambridge [UK] (CAM), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), Atacama Large Millimeter/submillimeter Array (ALMA), European Southern Observatory (ESO), Département de Physique des Particules (ex SPP) (DPhP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Département de Physique des Particules (ex SPP) (DPP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Perrott, Yvette Chanel [0000-0002-6255-8240], Rumsey, Clare [0000-0002-3936-2178], Lasenby, Anthony [0000-0002-8208-6332], Saunders, Richard [0000-0003-3167-5863], Titterington, David [0000-0003-1431-920X], Harrison, Diana [0000-0001-8687-6588], Stolyarov, Vladislav [0000-0001-8151-828X], and Apollo - University of Cambridge Repository

Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO), galaxies: clusters: intracluster medium, Arcminute Microkelvin Imager, FOS: Physical sciences, Flux, cosmic background radiation, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, clusters: intracluster medium [Galaxies], clusters: general [Galaxies], Cosmic background radiation, 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], symbols.namesake, Consistency (statistics), 0103 physical sciences, Cluster (physics), Range (statistics), Angular resolution, Planck, 010306 general physics, observations [Cosmology], 010303 astronomy & astrophysics, Galaxy cluster, Physics, Astronomy and Astrophysics, galaxies: clusters: general, Space and Planetary Science, X-rays: galaxies: clusters, cosmology: observations, symbols, galaxies: clusters [X-rays], Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We present observations and analysis of a sample of 123 galaxy clusters from the 2013 Planck catalogue of Sunyaev-Zel'dovich sources with the Arcminute Microkelvin Imager (AMI), a ground-based radio interferometer. AMI provides an independent measurement with higher angular resolution, 3 arcmin compared to the Planck beams of 5-10 arcmin. The AMI observations thus provide validation of the cluster detections, improved positional estimates, and a consistency check on the fitted 'size' ($\theta_{s}$) and 'flux' ($Y_{\rm tot}$) parameters in the Generalised Navarro, Frenk and White (GNFW) model. We detect 99 of the clusters. We use the AMI positional estimates to check the positional estimates and error-bars produced by the Planck algorithms PowellSnakes and MMF3. We find that $Y_{\rm tot}$ values as measured by AMI are biased downwards with respect to the Planck constraints, especially for high Planck-SNR clusters. We perform simulations to show that this can be explained by deviation from the 'universal' pressure profile shape used to model the clusters. We show that AMI data can constrain the $\alpha$ and $\beta$ parameters describing the shape of the profile in the GNFW model for individual clusters provided careful attention is paid to the degeneracies between parameters, but one requires information on a wider range of angular scales than are present in AMI data alone to correctly constrain all parameters simultaneously., Comment: 41 pages (20 + 21 of appendices), 38 figures. Accepted by A&A 11/06/2015. Minor changes only from v1; long delay in publication due to lack of response from first referee

Published
2015
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