Letter to the Editor

A search for debris disks in the Herschel-ATLAS ^*

¹ Centre for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Herts AL10 9AB, UK
² School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
³ Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281 S9, 9000 Gent, Belgium
⁴ Department of Physics and Astronomy, The Open University, Milton Keynes, MK7 6AA, UK
⁵ School of Physics and Astronomy, Cardiff University, The Parade, Cardiff, CF24 3AA, UK
⁶ The Rutherford Appleton Laboratory, Chilton, Didcot OX11 0NL, UK
⁷ Astrophysics Branch, NASA Ames Research Center, Mail Stop 245-6, Moffett Field, CA 94035, USA
⁸ UK Astronomy Technology Center, Royal Observatory Edinburgh, Edinburgh, EH9 3HJ, UK
⁹ Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK
¹⁰ Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1, Canada
¹¹ California Institute of Technology, 1200 East California Blvd., Pasadena, CA 91125, USA
¹² Dept. of Physics & Astronomy, University of California, Irvine, CA 92697, USA e-mail: mat@star.herts.ac.uk
¹³ Laboratoire d'Astrophysique de Marseille, UMR6110 CNRS, 38 rue F. Joliot-Curie, 13388 Marseille France
¹⁴ University of Padova, Department of Astronomy, Vicolo Osservatorio 3, 35122 Padova, Italy
¹⁵ Instituto de Astrofísica de Canarias, C/Vía Láctea s/n, 38200 La Laguna, Spain
¹⁶ Departamento de Astrofísica, Universidad de La Laguna, 38205 La Laguna, Tenerife, Spain
¹⁷ Astrophysics Group, Imperial College, Blackett Laboratory, Prince Consort Road, London SW7 2AZ, UK
¹⁸ National Radio Astronomy Observatory, PO Box 2, Green Bank, WV 24944, USA
¹⁹ Scuola Internazionale Superiore di Studi Avanzati, via Beirut 2-4, 34151 Triest, Italy
²⁰ Instituto de Física de Cantabria (CSIC-UC), Santander 39005, Spain
²¹ Institut d'Astrophysique Spatiale (IAS), Bâtiment 121, 91405 Orsay, France; and Université Paris-Sud 11 and CNRS (UMR 8617), France
²² Herschel Science Centre, ESAC, ESA, PO Box 78, Villanueva de la Cañada, 28691 Madrid, Spain
²³ Oxford Astrophysics, Denys Wilkinson Building, University of Oxford, Keble Road, Oxford, OX1 3RH, UK

Received: 31 March 2010
Accepted: 12 May 2010

Abstract

Aims. We aim to demonstrate that the Herschel-ATLAS (H-ATLAS) is suitable for a blind and unbiased survey for debris disks by identifying candidate debris disks associated with main sequence stars in the initial science demonstration field of the survey. We show that H-ATLAS reveals a population of far-infrared/sub-mm sources that are associated with stars or star-like objects on the SDSS main-sequence locus. We validate our approach by comparing the properties of the most likely candidate disks to those of the known population.

Methods. We use a photometric selection technique to identify main sequence stars in the SDSS DR7 catalogue and a Bayesian Likelihood Ratio method to identify H-ATLAS catalogue sources associated with these main sequence stars. Following this photometric selection we apply distance cuts to identify the most likely candidate debris disks and rule out the presence of contaminating galaxies using UKIDSS LAS K-band images.

Results. We identify 78 H-ATLAS sources associated with SDSS point sources on the main-sequence locus, of which two are the most likely debris disk candidates: H-ATLAS J090315.8 and H-ATLAS J090240.2. We show that they are plausible candidates by comparing their properties to the known population of debris disks. Our initial results indicate that bright debris disks are rare, with only 2 candidates identified in a search sample of 851 stars. We also show that H-ATLAS can derive useful upper limits for debris disks associated with Hipparcos stars in the field and outline the future prospects for our debris disk search programme.