Universität zu Köln

Henshaw, J. D., Longmore, S. N., Kruijssen, J. M. D., Davies, B., Bally, J., Barnes, A., Battersby, C., Burton, M., Cunningham, M. R., Dale, J. E., Ginsburg, A., Immer, K., Jones, P. A., Kendrew, S., Mills, E. A. C., Molinari, S., Moore, T. J. T., Ott, J., Pillai, T., Rathborne, J., Schilke, P., Schmiedeke, A., Testi, L., Walker, D., Walsh, A. and Zhang, Q. (2016). Molecular gas kinematics within the central 250 pc of the Milky Way. Mon. Not. Roy. Astron. Soc., 457 (3). S. 2675 - 2703. OXFORD: OXFORD UNIV PRESS. ISSN 1365-2966

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Abstract

Using spectral line observations of HNCO, N2H+, and HNC, we investigate the kinematics of dense gas in the central similar to 250 pc of the Galaxy. We present SCOUSE (Semi -automated multi-COmponent Universal Spectral-line fitting Engine), a line-fitting algorithm designed to analyse large volumes of spectral line data efficiently and systematically. Unlike techniques which do not account for complex line profiles, SCOUSE accurately describes the {l, b, v(LsR)} distribution of Central Molecular Zone (CMZ) gas, which is asymmetric about Sgr A* in both position and velocity. Velocity dispersions range from 2.6 km s(-1) < a < 53.1 km s (1) A median dispersion of 9.8 km s 1, translates to a Mach number, M-3D > 28. The gas is distributed throughout several 'streams', with projected lengths similar to 100-250 pc. We link the streams to individual clouds and sub-regions, including Sgr C, the 20 and 50 km s 1 clouds, the dust ridge, and Sgr B2. Shell-like emission features can be explained by the projection of independent molecular clouds in Sgr C and the newly identified conical profile of Sgr B2 in {l, b, vi sR} space. These features have previously invoked supernova-driven shells and cloud-cloud collisions as explanations. We instead caution against structure identification in velocity-integrated emission maps. Three geometries describing the 3D structure of the CMZ are investigated: (i) two spiral arms; (ii) a closed elliptical orbit; (iii) an open stream. While two spiral arms and an open stream qualitatively reproduce the gas distribution, the most recent parametrization of the closed elliptical orbit does not. Finally, we discuss how proper motion measurements of masers can distinguish between these geometries, and suggest that this effort should be focused on the 20 km s(-1) and 50 km s(-1) clouds and Sgr C.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Henshaw, J. D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Longmore, S. N. UNSPECIFIED UNSPECIFIED UNSPECIFIED Kruijssen, J. M. D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Davies, B. UNSPECIFIED UNSPECIFIED UNSPECIFIED Bally, J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Barnes, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Battersby, C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Burton, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Cunningham, M. R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Dale, J. E. UNSPECIFIED UNSPECIFIED UNSPECIFIED Ginsburg, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Immer, K. UNSPECIFIED UNSPECIFIED UNSPECIFIED Jones, P. A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Kendrew, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Mills, E. A. C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Molinari, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Moore, T. J. T. UNSPECIFIED UNSPECIFIED UNSPECIFIED Ott, J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Pillai, T. UNSPECIFIED UNSPECIFIED UNSPECIFIED Rathborne, J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Schilke, P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Schmiedeke, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Testi, L. UNSPECIFIED UNSPECIFIED UNSPECIFIED Walker, D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Walsh, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Zhang, Q. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-278778
DOI:	10.1093/mnras/stw121
Journal or Publication Title:	Mon. Not. Roy. Astron. Soc.
Volume:	457
Number:	3
Page Range:	S. 2675 - 2703
Date:	2016
Publisher:	OXFORD UNIV PRESS
Place of Publication:	OXFORD
ISSN:	1365-2966
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language GALACTIC PLANE SURVEY; HIGH-RESOLUTION OBSERVATIONS; CENTER CLOUD G0.253+0.016; MASSIVE STAR-FORMATION; CENTER DUST RIDGE; 1720 MHZ MASERS; SGR A-ASTERISK; LARGE-SCALE; CENTER REGION; BARRED POTENTIALS Multiple languages Astronomy & Astrophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/27877