Beuther, H, Bihr, S, Rugel, M, Johnston, K, Wang, Y, Walter, F, Brunthaler, A, Walsh, AJ, Ott, J, Stil, J, Henning, T, Schierhuber, T, Kainulainen, J, Heyer, M, Goldsmith, PF, Anderson, LD, Longmore, SN, Klessem, RS, Glover, SCO, Urquhart, JS et al, Plume, R, Ragan, SE, Schneider, N, McClure-Griffiths, NM, Menten, KM, Smith, R, Roy, N, Shanahan, R, Nguyen-Luong, Q and Bigiel, F (2016) The HI/OH/Recombination line survey of the inner Milky Way (THOR). Astronomy and Astrophysics. ISSN 0004-6361

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Abstract

Context: The past decade has witnessed a large number of Galactic plane surveys at angular resolutions below 20". However, no comparable high-resolution survey exists at long radio wavelengths around 21cm in line and continuum emission. Methods: Employing the Very Large Array (VLA) in the C-array configuration and a large program, we observe the HI 21cm line, four OH lines, nineteen Halpha radio recombination lines as well as the continuum emission from 1 to 2GHz in full polarization over a large part of the first Galactic quadrant. Results: Covering Galactic longitudes from 14.5 to 67.4deg and latitudes between +-1.25deg, we image all of these lines and the continuum at ~20" resolution. These data allow us to study the various components of the interstellar medium (ISM): from the atomic phase, traced by the HI line, to the molecular phase, observed by the OH transitions, to the ionized medium, revealed by the cm continuum and the Halpha radio recombination lines. Furthermore, the polarized continuum emission enables magnetic field studies. In this overview paper, we discuss the survey outline and present the first data release as well as early results from the different datasets. We now release the first half of the survey; the second half will follow later after the ongoing data processing has been completed. The data in fits format (continuum images and line data cubes) can be accessed through the project web-page http://www.mpia.de/thor. Conclusions: The HI/OH/Recombination line survey of the Milky Way (THOR) opens a new window to the different parts of the ISM. It enables detailed studies of molecular cloud formation, conversion of atomic to molecular gas, and feedback from HII regions as well as the magnetic field in the Milky Way. It is highly complementary to other surveys of our Galaxy, and comparing different datasets allows us to address many open questions.

Item Type:	Article
Uncontrolled Keywords:	astro-ph.GA; astro-ph.GA; astro-ph.SR
Subjects:	Q Science > QB Astronomy
Divisions:	Astrophysics Research Institute
Publisher:	EDP Sciences
Related URLs:	http://arxiv.org/abs/1609.03329v1
Date Deposited:	15 Sep 2016 11:08
Last Modified:	04 Sep 2021 12:31
DOI or ID number:	10.1051/0004-6361/201629143
URI:	https://researchonline.ljmu.ac.uk/id/eprint/4158

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