GASTON: Galactic Star Formation with NIKA2. Evidence for the mass growth
  of star-forming clumps
  Determining the mechanism by which high-mass stars are formed is essential
for our understanding of the energy budget and chemical evolution of galaxies.
By using the New IRAM KIDs Array 2 (NIKA2) camera on the Institut de Radio
Astronomie Millim\'etrique (IRAM) 30-m telescope, we have conducted
high-sensitivity and large-scale mapping of a fraction of the Galactic plane in
order to search for signatures of the transition between the high- and low-mass
star-forming modes. Here, we present the first results from the Galactic Star
Formation with NIKA2 (GASTON) project, a Large Programme at the IRAM 30-m
telescope which is mapping $\approx$2 deg$^2$ of the inner Galactic plane (GP),
centred on $\ell$=23.9$^\circ$, $b$=0.05$^\circ$, as well as targets in Taurus
and Ophiuchus in 1.15 and 2.00 mm continuum wavebands. In this paper we present
the first of the GASTON GP data taken, and present initial science results. We
conduct an extraction of structures from the 1.15 mm maps using a dendrogram
analysis and, by comparison to the compact source catalogues from Herschel
survey data, we identify a population of 321 previously-undetected clumps.
Approximately 80 per cent of these new clumps are 70 $\mu$m-quiet, and may be
considered as starless candidates. We find that this new population of clumps
are less massive and cooler, on average, than clumps that have already been
identified. Further, by classifying the full sample of clumps based upon their
infrared-bright fraction - an indicator of evolutionary stage - we find
evidence for clump mass growth, supporting models of clump-fed high-mass star
formation.
