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

I. Overview and first results for the Galactic longitude range 28° < l < 36°

¹ Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
e-mail: brunthal@mpifr-bonn.mpg.de
² National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903, USA
³ South African Radio Astronomy Observatory, 2 Fir St, Black River Park, Observatory 7925, South Africa
⁴ Centre for Astrophysics and Planetary Science, University of Kent, Ingram Building, Canterbury, Kent CT2 7NH, UK
⁵ Max Planck Institute for Astronomy, Koenigstuhl 17, 69117 Heidelberg, Germany
⁶ Instituto de Radioastronomía y Astrofísica (IRyA), Universidad Nacional Autónoma de México Morelia, 58089 Morelia, Mexico
⁷ Laboratoire d’astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615 Pessac, France
⁸ Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
⁹ Department of Earth & Space Sciences, Indian Institute of Space Science and Technology, Trivandrum 695547, India
¹⁰ Department of Physics, Indian Institute of Science, Bengaluru 560012, India

Received: 5 November 2020
Accepted: 5 May 2021

Abstract

Aims. Surveys of the Milky Way at various wavelengths have changed our view of star formation in our Galaxy considerably in recent years. In this paper we give an overview of the GLOSTAR survey, a new survey covering large parts (145 square degrees) of the northern Galactic plane using the Karl G. Jansky Very Large Array in the frequency range 4−8 GHz and the Effelsberg 100-m telescope. This provides for the first time a radio survey covering all angular scales down to 1.5 arcsecond, similar to complementary near-IR and mid-IR galactic plane surveys. We outline the main goals of the survey and give a detailed description of the observations and the data reduction strategy.

Methods. In our observations we covered the radio continuum in full polarization, as well as the 6.7 GHz methanol maser line, the 4.8 GHz formaldehyde line, and seven radio recombination lines. The observations were conducted in the most compact D configuration of the VLA and in the more extended B configuration. This yielded spatial resolutions of 18″ and 1.5″ for the two configurations, respectively. We also combined the D configuration images with the Effelsberg 100-m data to provide zero spacing information, and we jointly imaged the D- and B-configuration data for optimal sensitivity of the intermediate spatial ranges.

Results. Here we show selected results for the first part of the survey, covering the range of 28° < l < 36° and |b|< 1°, including the full low-resolution continuum image, examples of high-resolution images of selected sources, and the first results from the spectral line data.