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Milky way kinematics. II. A uniform inner galaxy H I terminal velocity curve

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journal contribution
posted on 2024-11-01, 03:26 authored by NM McClure-Griffiths, John DickeyJohn Dickey
Using atomic hydrogen (H I) data from the VLA Galactic Plane Survey, we measure the H I terminal velocity as a function of longitude for the first quadrant of the Milky Way. We use these data, together with our previous work on the fourth Galactic quadrant, to produce a densely sampled, uniformly measured, rotation curve of the northern and southern Milky Way between 3 kpc < R < 8 kpc. We determine a new joint rotation curve fit for the first and fourth quadrants, which is consistent with the fit we published in McClure-Griffiths & Dickey and can be used for estimating kinematic distances interior to the solar circle. Structure in the rotation curves is now exquisitely well defined, showing significant velocity structure on lengths of ∼200 pc, which is much greater than the spatial resolution of the rotation curve. Furthermore, the shape of the rotation curves for the first and fourth quadrants, even after subtraction of a circular rotation fit shows a surprising degree of correlation with a roughly sinusoidal pattern between 4.2 < R < 7 kpc.

Funding

Australian Research Council

History

Publication title

The Astrophysical Journal

Volume

831

Issue

2

Article number

124

Number

124

Pagination

1-8

ISSN

0004-637X

Department/School

School of Natural Sciences

Publisher

Univ Chicago Press

Publication status

  • Published

Place of publication

1427 E 60Th St, Chicago, USA, Il, 60637-2954

Rights statement

Copyright 2016 The American Astronomical Society

Socio-economic Objectives

280120 Expanding knowledge in the physical sciences

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