The Herschel InfraRed Galactic Plane Survey: A Panoramic View of Star Formation in the Milky Way
2018 September 14
Hi-GAL, the Herschel unbiased survey of the entire Galactic plane (70-500 μm), made available a vast mine of regions for studying early phases of star formation, especially in the high-mass regime, in different Galactic environments, providing an overall view of the Milky Way as a star formation engine. Here we present the first release of the Hi-GAL physical catalog, constituted by about 140000 entries, namely the compact sources detected by Herschel and showing a regular spectral energy distribution, eligible for grey-body fit. Complementary MSX, WISE, MIPSGAL, ATLASGAL and BGPS photometry was also used to extend the wavelength coverage. A large fraction of sources in the catalog is associated with a heliocentric distance estimate, which range from < 1 kpc to > 15 kpc, so that our sample of compact sources spans more than two orders of magnitude of linear sizes, corresponding to different object classes (from cores to clumps and even small clouds). This allows us to study the behaviour of star-forming structures on different spatial scales. Furthermore, we use source properties as temperature, mass, surface density, bolometric luminosity to build an evolutionary picture, and to search for conditions for high-mass star formation to occur.