A global view on star formation: The GLOSTAR Galactic plane survey

IX. Radio Source Catalog III: 2° < ℓ < 28°, 36° < ℓ < 40°, 56° < ℓ < 60° and |b| < 1°, VLA B-configuration^★

¹ National Astronomical Observatories, Chinese Academy of Sciences, A20 Datun Road, Chaoyang District, Beijing 100101, PR China
e-mail: yangay@nao.cas.cn
² Key Laboratory of Radio Astronomy and Technology, Chinese Academy of Sciences, A20 Datun Road, Chaoyang District, Beijing 100101, PR China
³ Max-Planck-Institut für Radioastronomie (MPIfR), Auf dem Hügel 69, 53121 Bonn, Germany
e-mail: ayyang@mpifr-bonn.mpg.de
⁴ IRAM, 300 rue de la piscine, 38406 Saint-Martin-d’Hères, France
⁵ Centre for Astrophysics and Planetary Science, University of Kent, Canterbury, CT2 7NH, UK
⁶ German Aerospace Center, Scientific Information, 51147 Cologne, Germany
⁷ Instituto Nacional de Astrofísica, Óptica y Electrónica, Apartado Postal 51 y 216, 72000 Puebla, Mexico
⁸ National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903, USA
⁹ Center for Astrophysics | Harvard & Smithsonian, 60 Garden St., Cambridge, MA 02138, USA
¹⁰ National Radio Astronomy Observatory, PO Box O, 1003 Lopezville Rd, Socorro, NM 87801, USA
¹¹ Max Planck Institute for Astronomy, Koenigstuhl 17, 69117 Heidelberg, Germany
¹² Department of Earth & Space Sciences, Indian Institute of Space Science and Technology, Trivandrum 695547, India
¹³ Laboratoire d’astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615 Pessac, France
¹⁴ I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
¹⁵ Department of Physics, Indian Institute of Science, Bangalore 560012, India
¹⁶ Instituto de Radioastronomía y Astrofísica (IRyA), Universidad Nacional Autónoma de México, Morelia 58089, Mexico

Received: 26 July 2023
Accepted: 12 October 2023

Abstract

As part of the GLObal view of STAR formation in the Milky Way (GLOSTAR) survey, we present the high-resolution continuum source catalog for the regions (ℓ = 2° −28°, 36° −40°, 56° −60°, and |b| < 1.0°), observed with the Karl G. Jansky Very Large Array (VLA) in its B-configuration. The continuum images were optimized to detect compact sources on angular scales up to 4″, and have a typical noise level of 1σ ~ 0.08 mJy beam⁻¹ for an angular resolution of 1″, which makes GLOSTAR currently the highest resolution as well as the most sensitive radio survey of the northern Galactic plane at 4–8 GHz. We extracted 13354 sources above a threshold of 5σ and 5437 sources above 7σ that represent the high-reliability catalog. We determined the in-band spectral index (α) for the sources in the 7σ-threshold catalog. The mean value is α = −0.6, which indicates that the catalog is dominated by sources emitting nonthermal radio emission. We identified the most common source types detected in radio surveys: 251 H II region candidates (113 new), 282 planetary nebulae (PNe) candidates (127 new), 784 radio star candidates (581 new), and 4080 extragalactic radio source candidates (2175 new). A significant fraction of H II regions and PNe candidates have α < −0.1 indicating that these candidates could contain radio jets, winds or outflows from high-mass and low-mass stellar objects. We identified 245 variable radio sources by comparing the flux densities of compact sources from the GLOSTAR survey and the Co-Ordinated Radio “N” Infrared Survey for High-mass star formation (CORNISH), and find that most of them are infrared quiet. The catalog is typically 95% complete for point sources at a flux density of 0.6 mJy (i.e., a typical 7σ level) and the systematic positional uncertainty is ≲ 0″.1.