We present two new radio continuum images from the Australian Square Kilometre Array Pathfinder (ASKAP) survey in the direction of the Small Magellanic Cloud (SMC). These images are part of the Evolutionary Map of the Universe (EMU) Early Science Project (ESP) survey of the Small and Large Magellanic Clouds. The two new source lists produced from these images contain radio continuum sources observed at 960 MHz (4489 sources) and 1320 MHz (5954 sources) with a bandwidth of 192 MHz and beam sizes of 30.0 × 30.0 arcsec2 and 16.3 × 15.1 arcsec2, respectively. The median root mean square (RMS) noise values are 186 μJy beam−1 (960 MHz) and 165 μJy beam−1 (1320 MHz). To create point source catalogues, we use these two source lists, together with the previously published Molonglo Observatory Synthesis Telescope (MOST) and the Australia Telescope Compact Array (ATCA) point source catalogues to estimate spectral indices for the whole population of radio point sources found in the survey region. Combining our ASKAP catalogues with these radio continuum surveys, we found 7736 point-like sources in common over an area of 30 deg2. In addition, we report the detection of two new, low surface brightness supernova remnant candidates in the SMC. The high sensitivity of the new ASKAP ESP survey also enabled us to detect the bright end of the SMC planetary nebula sample, with 22 out of 102 optically known planetary nebulae showing point-like radio continuum emission. Lastly, we present several morphologically interesting background radio galaxies.
Bibliographical noteFunding Information:
1Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK 2Western Sydney University, Locked Bag 1797, Penrith South DC, NSW 2751, Australia 3CSIRO Astronomy and Space Science, PO Box 76, Epping, NSW 1710, Australia 4Depto. de Astronomía, DCNE, Universidad de Guanajuato, Apdo. Postal 144, Guanajuato, CP 36000, Mexico 5INAF Osservatorio Astrofisico di Catania, via Santa Sofia 78, I-95123 Catania, Italy 6School of Physics, The University of New South Wales, Sydney 2052, Australia 7The Inter-University Institute for Data Intensive Astronomy (IDIA), Department of Astronomy, University of Cape Town, Rondebosch 7701, South Africa 8ASTRON – Netherlands Institute for Radio Astronomy, NL-7991 PD Dwingeloo, the Netherlands 9Institute for Advanced Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan 10Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan 11Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße, D-85748 Garching, Germany 12National Radio Astronomy Observatory, 1003 Lopezville Rd., Socorro, NM 87801, USA
The Australian SKA Pathfinder (ASKAP) is part of the Australian Telescope which is funded by the Commonwealth of Australia for operation as National Facility managed by CSIRO. We used the KARMA and MIRIAD software packages developed by the Australia Telescope National Facility (ATNF). Operation of ASKAP is funded by the Australian Government with support from the National Collaborative Research Infrastructure Strategy. ASKAP uses the resources of the Pawsey Supercomputing Centre. Establishment of ASKAP, the Murchison Radio-astronomy Observatory and the Pawsey Supercomputing Centre are initiatives of the Australian Government, with support from the Government of Western Australia and the Science and Industry Endowment Fund. We acknowledge the Wajarri Yamatji people as the traditional owners of the Observatory site. TDJ. acknowledges support for this research from a Royal Society Newton International Fellowship, NF171032. MJM acknowledges the support of the National Science Centre, Poland, through the SONATA BIS grant 2018/30/E/ST9/00208. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. Partial support for L.R. comes from U.S. National Science Foundation grant AST1714205 to the University of Minnesota. Project/paper is partially supported by the National Natural Science Foundation of China No. 11690024, Chinese Academy of Sciences International Partnership No. 114A11KYSB20160008. This work is part of the project 176005 ?Emission nebulae: structure and evolution? supported by the Ministry of Education, Science, and Technological Development of the Republic of Serbia. H.A. benefited from project CIIC 218/2019 of University of Guanajuato. The authors would like to thank the anonymous referee for a constructive report and useful comments.
© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society
- Magellanic Clouds