Gas kinematics in high-mass star-forming regions from the Perseus spiral arm
Journal article, 2017

We present results of a survey of 14 star-forming regions from the Perseus spiral armin CS (2-1) and (CO)-C-13 (1-0) lines with the Onsala Space Observatory 20 m telescope. Maps of 10 sources in both lines are obtained. For the remaining sources a map in just one line or a single-point spectrum is obtained. On the basis of newly obtained and published observational data we consider the relation between velocities of the "quasi-thermal" CS (2-1) line and 6.7 GHz methanol maser line in 24 high-mass star-forming regions in the Perseus arm. We show that, surprisingly, velocity ranges of 6.7 GHz methanol maser emission are predominantly red-shifted with respect to corresponding CS (2-1) line velocity ranges in the Perseus arm. We suggest that the predominance of the "red-shifted masers" in the Perseus arm could be related to the alignment of gas flows caused by the large-scalemotions in the Galaxy. Large-scale galactic shock related to the spiral structure is supposed to affect the local kinematics of the star-forming regions. Part of the Perseus arm, between galactic longitudes from 85A degrees to 124A degrees , does not contain blue-shifted masers at all. Radial velocities of the sources are the greatest in this particular part of the arm, so the velocity difference is clearly pronounced. (CO)-C-13 (1-0) and CS (2-1) velocity maps of G183.35-0.58 show gas velocity difference between the center and the periphery of the molecular clump up to 1.2 km s(-1). Similar situation is likely to occur in G85.40-0.00. This can correspond to the case when the large-scale shock wave entrains the outer parts of a molecular clump in motion while the dense central clump is less affected by the shock.

Molecular Cloud


6.7 Ghz

Noncircular Motions


Young Stellar Objects

H-Ii Regions

6.7-Ghz Methanol Masers

Galactic Plane


M. S. Kirsanova

Russian Academy of Sciences

A. M. Sobolev

Ural Federal University

Magnus Thomasson

Chalmers, Earth and Space Sciences, Onsala Space Observatory

Astronomy Reports

1063-7729 (ISSN) 1562-6881 (eISSN)

Vol. 61 9 760-774

Subject Categories

Astronomy, Astrophysics and Cosmology



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