CHIMPS: the13CO/C18O (J = 3 → 2) Heterodyne Inner Milky Way Plane Survey

Rigby, A. J. and Moore, T. J. T. and Plume, R. and Eden, D. J. and Urquhart, J.S. and Thompson, M. A. and Mottram, J. C. and Brunt, C. M. and Butner, H. M. and Dempsey, J. T. and Gibson, S. J. and Hatchell, J. and Jenness, T. and Kuno, N. and Longmore, S. N. and Morgan, L. K. and Polychroni, D. and Thomas, H. and White, G. J. and Zhu, M. (2016) CHIMPS: the13CO/C18O (J = 3 → 2) Heterodyne Inner Milky Way Plane Survey. Monthly Notices of the Royal Astronomical Society, 456 (3). pp. 2885-2899. ISSN 0035-8711. (doi:https://doi.org/10.1093/mnras/stv2808) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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Official URL
http://doi.org/10.1093/mnras/stv2808

Abstract

We present the 13CO/C18O (J = 3 → 2) Heterodyne Inner Milky Way Plane Survey (CHIMPS) which has been carried out using the Heterodyne Array Receiver Program on the 15 m James Clerk Maxwell Telescope (JCMT) in Hawaii. The high-resolution spectral survey currently covers |b| ≤ 0.5° and 28° ≲ l ≲ 46°, with an angular resolution of 15 arcsec in 0.5 km s-1 velocity channels. The spectra have a median rms of ˜0.6 K at this resolution, and for optically thin gas at an excitation temperature of 10 K, this sensitivity corresponds to column densities of NH2 ˜ 3 × 1020 cm-2 and NH2 ˜ 4 × 1021 cm-2 for 13CO and C18O, respectively. The molecular gas that CHIMPS traces is at higher column densities and is also more optically thin than in other publicly available CO surveys due to its rarer isotopologues, and thus more representative of the three-dimensional structure of the clouds. The critical density of the J = 3 → 2 transition of CO is ≳104 cm-3 at temperatures of ≤20 K, and so the higher density gas associated with star formation is well traced. These data complement other existing Galactic plane surveys, especially the JCMT Galactic Plane Survey which has similar spatial resolution and column density sensitivity, and the Herschel infrared Galactic Plane Survey. In this paper, we discuss the observations, data reduction and characteristics of the survey, presenting integrated-emission maps for the region covered. Position-velocity diagrams allow comparison with Galactic structure models of the Milky Way, and while we find good agreement with a particular four-arm model, there are some significant deviations.

Item Type: Article
Uncontrolled keywords: molecular data, surveys, stars: formation, ISM: molecules, ISM: structure, submillimetre: ISM
Subjects: Q Science > QB Astronomy > QB460 Astrophysics
Divisions: Faculties > Sciences > School of Physical Sciences > Centre for Astrophysics and Planetary Sciences
Depositing User: James Urquhart
Date Deposited: 04 May 2016 13:29 UTC
Last Modified: 26 May 2018 20:04 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/55240 (The current URI for this page, for reference purposes)
Urquhart, J.S.: https://orcid.org/0000-0002-1605-8050
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