GASTON: Galactic Star Formation with NIKA2: A new population of cold massive sources discovered

TL;DR

GASTON, a large survey using NIKA2 on the IRAM 30m telescope, discovered a new population of cold, compact sources in the Galactic plane, advancing understanding of high-mass star formation and stellar mass determination.

Contribution

This study presents the first results of GASTON, revealing a previously undetected population of cold, low-brightness sources in the Galactic plane, with implications for star formation theories.

Findings

Approximately 25% of detected sources are new discoveries.

Identified a population of cold, compact sources undetected in previous surveys.

Preliminary analysis suggests potential evolution in the mass distribution over time.

Abstract

Understanding where and when the mass of stars is determined is one of the fundamental, mostly unsolved, questions in astronomy. Here, we present the first results of GASTON, the Galactic Star Formation with NIKA2 large programme on the IRAM 30m telescope, that aims to identify new populations of low-brightness sources to tackle the question of stellar mass determination across all masses. In this paper, we focus on the high-mass star formation part of the project, for which we map a $\sim2$ deg$^2$ region of the Galactic plane around $l=24^\circ$ in both 1.2 mm and 2.0 mm continuum. Half-way through the project, we reach a sensitivity of 3.7 mJy/beam at 1.2mm. Even though larger than our target sensitivity of 2 mJy, the current sensitivity already allows the identification of a new population of cold, compact sources that remained undetected in any (sub-)mm Galactic plane survey so far. In fact, about 25% of the $\sim 1600$ compact sources identified in the 1.2 mm GASTON image are new detections. We present a preliminary analysis of the physical properties of the GASTON sources as a function of their evolutionary stage, arguing for a potential evolution of the mass distribution of these sources with time.