A global view on star formation: The GLOSTAR Galactic Plane Survey. I. Overview and first results for the Galactic longitude range 28{\deg} < l < 36{\deg}

TL;DR

The GLOSTAR Galactic Plane Survey provides a comprehensive radio view of star-forming regions in the northern Milky Way, combining multiple configurations and wavelengths to reveal structures from large scales down to 1.5 arcseconds.

Contribution

This paper introduces the GLOSTAR survey, detailing its methodology, data collection, and initial results, offering new high-resolution radio data of the Galactic plane.

Findings

First radio survey covering all angular scales down to 1.5 arcseconds.

Detection of various star formation tracers like methanol masers and radio recombination lines.

Initial high-resolution images of selected Galactic sources.

Abstract

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