GASS: The Parkes Galactic All-Sky Survey Update: improved correction for instrumental effects and new data release

• Published in: Astronomy and astrophysics (Berlin) Vol. 578; p. A78
• Main Authors: Kalberla, P M W, Haud, U
• Format: Journal Article
• Language: English
• Published: 01.06.2015
• Subjects: Algorithms; Channels; Cubes; Deviation; Sky surveys (astronomy); Spectra; Telescopes; Websites
• ISSN: 0004-6361; 1432-0746
• DOI: 10.1051/0004-6361/201525859

The Galactic All-Sky Survey (GASS) is a survey of Galactic atomic hydrogen (H I) emission in the southern sky observed with the Parkes 64m Radio Telescope. The first data release (GASS I) concerned survey goals and observing techniques, the second release (GASS II) focused on stray radiation and instrumental corrections. We seek to remove the remaining instrumental effects and present a third data release. Individual telescope records are compared with averages on the nearest grid position for significant deviations. In the last step we generate 3D FITS data cubes and examine them for remaining problems. We have removed weak, but systematic baseline offsets with an improved baseline fitting algorithm. We find that in total ~1.5% of the telescope dumps need to be discarded in addition to ~0.5% of the spectral channels that were excluded in GASS II. The new data release (GASS III) facilitates data products with improved quality. A new web interface, compatible with the previous version, is available for download of GASS III FITS cubes and spectra.