GASKAP -- A Galactic Spectral Line Survey with the Australian Square Kilometre Array Pathfinder

TL;DR

GASKAP is a high-sensitivity, wide-field spectral line survey using ASKAP to study neutral and molecular gas in the Milky Way, Magellanic Clouds, and Stream, addressing matter exchange between the galaxy disk and halo.

Contribution

This paper introduces the GASKAP survey, leveraging ASKAP's capabilities for high-resolution, rapid spectral line mapping of the Galactic Plane and Magellanic Clouds.

Findings

High-resolution maps of HI and OH emission will be produced.

Insights into gas exchange processes between the galaxy disk and halo.

Enhanced understanding of the Magellanic Stream's composition and dynamics.

Abstract

One of the Survey Science Projects that the Australian Square Kilometre Array Pathfinder (ASKAP) telescope will do in its first few years of operation is a study of the 21-cm line of HI and the 18-cm lines of OH in the Galactic Plane and the Magellanic Clouds and Stream. The wide-field ASKAP can survey a large area with very high sensitivity much faster than a conventional telescope because of its focal plane array of receiver elements. The brightness sensitivity for the widespread spectral line emission of the interstellar medium depends on the beam size and the survey speed. In the GASKAP survey, maps with different resolutions will be synthesized simultaneously; these will be matched to different scientific applications such as diffuse HI and OH emission, OH masers, and HI absorption toward background continuum sources. A great many scientific questions will be answered by the GASKAP survey results; a central topic is the exchange of matter and energy between the Milky Way disk and halo. The survey will show how neutral gas at high altitude (z) above the disk, like the Magellanic Stream, makes its way down through the halo, what changes it experiences along the way, and how much is left behind.