dc.identifier.citation | Elia , D , Schisano , E , Molinari , S , Robitaille , T , Anglés-Alcázar , D , Bally , J , Battersby , C , Benedettini , M , Billot , N , Calzoletti , L , Di Giorgio , A M , Faustini , F , Li , J Z , Martin , P , Morgan , L , Motte , F , Mottram , J C , Natoli , P , Olmi , L , Paladini , R , Piacentini , F , Pestalozzi , M , Pezzuto , S , Polychroni , D , Smith , M , Strafella , F , Stringfellow , G S , Testi , L , Thompson , M A , Traficante , A & Veneziani , M 2010 , ' A Herschel study of YSO evolutionary stages and formation timelines in two fields of the Hi-GAL survey ' , Astronomy and Astrophysics , vol. 518 , L97 . https://doi.org/10.1051/0004-6361/201014651 | |
dc.description.abstract | We present a first study of the star-forming compact dust condensations revealed by Herschel in the two 2 \times 2 \degr Galactic Plane fields centered at [l;b] = [30\degr; 0 \degr] and [l;b] = [59\degr; 0 \degr], respectively, and observed during the Science Demonstration Phase for the Herschel infrared Galactic Plane survey (Hi-GAL) Key-Project. Compact source catalogs extracted for the two fields in the five Hi-GAL bands (70, 160, 250, 350 and 500 $\mu$m) were merged based on simple criteria of positional association and spectral energy distribution (SED) consistency into a final catalog which contains only coherent SEDs with counterparts in at least three adjacent Herschel bands. These final source lists contain 528 entries for the l = 30\degr field, and 444 entries for the l = 59\degr field. The SED coverage has been augmented with ancillary data at 24 $\mu$m and 1.1 mm. SED modeling for the subset of 318 and 101 sources (in the two fields, respectively) for which the distance is known was carried out using both a structured star/disk/envelope radiative transfer model and a simple isothermal grey-body. Global parameters like mass, luminosity, temperature and dust properties have been estimated. The Lbol/Menv ratio spans four orders of magnitudes from values compatible with the pre-protostellar phase to embedded massive zero-age main sequence stars. Sources in the l = 59\degr field have on average lower L/M, possibly outlining an overall earlier evolutionary stage with respect to the sources in the l = 30\degr field. Many of these cores are actively forming high-mass stars, although the estimated core surface densities appear to be an order of magnitude below the 1 g cm$^{-2}$ critical threshold for high-mass star formation. | en |