Hi-GAL: the Herschel infrared Galactic Plane Survey

TL;DR

Hi-GAL is a comprehensive infrared survey of the Galactic Plane using Herschel, aimed at understanding star formation, molecular clouds, and interstellar medium structures across various Galactic environments.

Contribution

It provides the first homogeneous, multi-wavelength census of star-forming regions and cold structures in the Galactic Plane, enabling evolutionary studies of high-mass star formation.

Findings

Detection of early phases of molecular cloud and star formation.

A homogeneous dataset for studying temperature, luminosity, and mass of sources.

Insights into the environmental regulation of star formation processes.

Abstract

Hi-GAL, the Herschel infrared Galactic Plane Survey, is an Open Time Key Project of the Herschel Space Observatory. It will make an unbiased photometric survey of the inner Galactic Plane by mapping a two-degree wide strip in the longitude range |l|<60 degrees in five wavebands between 70um and 500um. The aim of Hi-GAL is to detect the earliest phases of the formation of molecular clouds and high-mass stars and to use the optimum combination of Herschel wavelength coverage, sensitivity, mapping strategy and speed to deliver a homogeneous census of star-forming regions and cold structures in the interstellar medium. The resulting representative samples will yield the variation of source temperature, luminosity, mass and age in a wide range of Galactic environments at all scales from massive YSOs in protoclusters to entire spiral arms, providing an evolutionary sequence for the formation of intermediate and high-mass stars. This information is essential to the formulation of a predictive global model of the role of environment and feedback in regulating the star-formation process. Such a model is vital to understanding star formation on galactic scales and in the early Universe. Hi-GAL will also provide a science legacy for decades to come with incalculable potential for systematic and serendipitous science in a wide range of astronomical fields, enabling the optimum use of future major facilities such as JWST and ALMA.