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Continuum sources from the THOR survey between 1 and 2 GHz

Bihr, S., Johnston, K.G., Beuther, H., Anderson, L.D., Ott, J., Rugel, M., Bigiel, F., Brunthaler, A., Glover, S.C.O., Henning, T., and others. (2016) Continuum sources from the THOR survey between 1 and 2 GHz. Astronomy and Astrophysics, 588 . ISSN 0004-6361. (doi:10.1051/0004-6361/201527697) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided. (Contact us about this Publication)
Official URL
http://dx.doi.org/10.1051/0004-6361/201527697

Abstract

We carried out a large program with the Karl G. Jansky Very Large Array (VLA): “THOR: The H?I, OH, Recombination line survey of the Milky Way”. We observed a significant portion (~100?deg2) of the Galactic plane in the first quadrant of the Milky Way in the 21?cm H?I line, 4 OH transitions, 19 radio recombination lines, and continuum from 1 to 2?GHz. In this paper we present a catalog of the continuum sources in the first half of the survey (l = 14.0?37.9° and l = 47.1?51.2°, | b | ? 1.1°) at a spatial resolution of 10?25?, depending on the frequency and sky position with a spatially varying noise level of ~0.3?1?mJy?beam-1. The catalog contains ~4400 sources. Around 1200 of these are spatially resolved, and ~1000 are possible artifacts, given their low signal-to-noise ratios. Since the spatial distribution of the unresolved objects is evenly distributed and not confined to the Galactic plane, most of them are extragalactic. Thanks to the broad bandwidth of the observations from 1 to 2?GHz, we are able to determine a reliable spectral index for ~1800 sources. The spectral index distribution reveals a double-peaked profile with maxima at spectral indices of ? ? ?1 and ? ? 0, corresponding to steep declining and flat spectra, respectively. This allows us to distinguish between thermal and non-thermal emission, which can be used to determine the nature of each source. We examine the spectral index of ~300 known H?II regions, for which we find thermal emission with spectral indices around ? ? 0. In contrast, supernova remnants (SNR) show non-thermal emission with ? ? ?0.5 and extragalactic objects generally have a steeper spectral index of ? ? ?1. Using the spectral index information of the THOR survey, we investigate potential SNR candidates. We classify the radiation of four SNR candidates as non-thermal, and for the first time, we provide strong evidence for the SNR origin of these candidates.

Item Type: Article
DOI/Identification number: 10.1051/0004-6361/201527697
Additional information: Unmapped bibliographic data: C7 - A97 [EPrints field already has value set] LA - English [Field not mapped to EPrints] J2 - Astron. Astrophys. [Field not mapped to EPrints] AD - Max-Planck Institute for Astronomy, Königstuhl 17, Heidelberg, Germany [Field not mapped to EPrints] AD - School of Physics and Astronomy, University of Leeds, Leeds, United Kingdom [Field not mapped to EPrints] AD - Department of Physics and Astronomy, West Virginia University, Morgantown, WV, United States [Field not mapped to EPrints] AD - National Radio Astronomy Observatory, 1003 Lopezville Road, Socorro, NM, United States [Field not mapped to EPrints] AD - Universität Heidelberg, Zentrum für Astronomie, Institut für Theoretische Astrophysik, Albert-Ueberle-Str. 2, Heidelberg, Germany [Field not mapped to EPrints] AD - Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, Bonn, Germany [Field not mapped to EPrints] AD - Department of Astronomy, University of Massachusetts, Amherst, MA, United States [Field not mapped to EPrints] AD - Astrophysics Research Institute, Liverpool John Moores University, 146 Brownlow Hill, Liverpool, United Kingdom [Field not mapped to EPrints] AD - Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT, Australia [Field not mapped to EPrints] AD - Department of Physics and Astronomy, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada [Field not mapped to EPrints] AD - Centre for Astrophysics and Planetary Science, University of Kent, Canterbury, United Kingdom [Field not mapped to EPrints] AD - International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth, WA, Australia [Field not mapped to EPrints] DB - Scopus [Field not mapped to EPrints] M3 - Article [Field not mapped to EPrints]
Uncontrolled keywords: Catalogs, Radio continuum: general, Surveys, Techniques: interferometric, Atmospheric optics, Galaxies, Optical waveguides, Surveying, Surveys, Catalogs, Extragalactic objects, Nonthermal emission, Radio continuum: general, Radio Recombination Lines, Recombination lines, Signaltonoise ratio (SNR), Techniques: interferometric, Signal to noise ratio
Subjects: Q Science > QB Astronomy > QB460 Astrophysics
Divisions: Faculties > Sciences > School of Physical Sciences > Centre for Astrophysics and Planetary Sciences
Depositing User: James Urquhart
Date Deposited: 04 May 2016 13:56 UTC
Last Modified: 29 May 2019 17:17 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/55233 (The current URI for this page, for reference purposes)
Urquhart, J.S.: https://orcid.org/0000-0002-1605-8050
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