The Interstellar Medium: The Key Component in Galactic Evolution and Modern Cosmology

Abstract

The gases of the interstellar medium (ISM) possess orders of magnitude more mass than those of all the stars combined and are thus the prime component of the baryonic universe. With L-band surface sensitivity even better than the planned phase one Square-Kilometer-Array (SKA1), the Five-hundred-meter Aperture Spherical radio Telescope (FAST) promises unprecedented insights into two of the primary components of ISM, namely, the atomic hydrogen (HI) and the hydroxyl molecule (OH). We discuss here the evolving landscape of our understanding of ISM, particularly, its complex phases, the magnetic fields within, the so-called dark molecular gas (DMG), high velocity clouds, and the connection between local and distant ISM. We lay out, in broad strokes, several expected FAST projects, including an all northern-sky high-resolution HI survey (22,000 deg${}^2$, 3\arcmin\ FWHM beam, 0.2 km/s), targeted OH mapping, searching for absorption or masing signals, and etc. Currently under commissioning, the commensal observing mode of FAST will be capable of simultaneously obtaining HI and pulsar data streams, making large-scale surveys in both science areas more efficient.

10 pages, 5 figures, published as part of the RAA February special volume on the science potential of FAST

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Cited by in corpus (6)

• Planning the scientific applications of the Five-hundred-meter Aperture Spherical radio Telescope
• Molecular Clump Extraction Algorithm Based on Local Density Clustering
• A FAST Survey of HINSA in PGCCs Guided by HC3N
• The physical and the geometrical properties of simulated cold HI structures
• A power spectral study of PHANGS galaxies with JWST MIRI: On the spatial scales of dust and PAHs
• Cosmic Radioactivity and Galactic Chemical Evolution