Characterization of unresolved and unclassified sources detected in radio continuum surveys of the Galactic plane

Chakraborty, A and Roy, N and Wang, Y and Datta, A and Beuther, H and Medina, SNX and Menten, KM and Urquhart, JS and Brunthaler, A and Dzib, SA (2020) Characterization of unresolved and unclassified sources detected in radio continuum surveys of the Galactic plane. In: Monthly Notices of the Royal Astronomical Society, 492 (2). pp. 2236-2240.

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Abstract

The continuum emission from 1 to 2 GHz of The H I/OH/Recombination line survey of the inner Milky Way (THOR) at �18 arcsec resolution covers �132 deg2 of the Galactic plane and detects 10 387 sources. Similarly, the first data release of the Global View of Star Formation in the Milky Way (GLOSTAR) survey covers �16 deg2 of the Galactic plane from 4 to 8 GHz at 18 arcsec resolution and detects 1575 sources. However, a large fraction of the unresolved discrete sources detected in these radio continuum surveys of the Galactic plane remain unclassified. Here, we study the Euclidean-normalized differential source counts of unclassified and unresolved sources detected in these surveys and compare them with simulated extragalactic radio source populations and previously established source counts. We find that the differential source counts for THOR and GLOSTAR surveys are in excellent agreement with both simulation and previous observations. We also estimate the angular two-point correlation function of unclassified and unresolved sources detected in THOR survey. We find a higher clustering amplitude in comparison with the Faint Images of the Radio Sky at Twenty-cm (FIRST) survey up to the angular separation of 5�. The decrease in angular correlation with increasing flux cut and the excellent agreement of clustering pattern of sources above 1 mJy with high-z samples (z > 0.5) of the FIRST survey indicates that these sources might be high-z extragalactic compact objects. The similar pattern of one-point and two-point statistics of unclassified and compact sources with extragalactic surveys and simulations confirms the extragalactic origin of these sources.

Item Type:	Journal Article
Publication:	Monthly Notices of the Royal Astronomical Society
Publisher:	Oxford University Press
Additional Information:	Copyright for this article belongs to Oxford University Press
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	11 Sep 2020 06:59
Last Modified:	11 Sep 2020 06:59
URI:	http://eprints.iisc.ac.in/id/eprint/65125

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