J/ApJ/831/124 Milky Way kinematics. II. (McClure-Griffiths+, 2016)
Milky Way kinematics.
II. A uniform inner galaxy H I terminal velocity curve.
McClure-Griffiths N.M., Dickey J.M.
<Astrophys. J., 831, 124-124 (2016)>
=2016ApJ...831..124M 2016ApJ...831..124M (SIMBAD/NED BibCode)
ADC_Keywords: Galactic plane ; H I data ; Surveys
Keywords: Galaxy: kinematics and dynamics; ISM: kinematics and dynamics;
radio lines: ISM
Abstract:
Using atomic hydrogen (HI) data from the VLA Galactic Plane Survey, we
measure the HI 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 3kpc<R<8kpc. 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
(Paper I, 2007ApJ...671..427M 2007ApJ...671..427M) 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 ∼200pc, 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<7kpc.
Description:
The HI data used here are from the VLA Galactic Plane Survey (VGPS;
Stil+ 2006AJ....132.1158S 2006AJ....132.1158S). The VGPS is a survey of a 21cm continuum
and HI emission and absorption obtained with the Very Large Array in
its D-array configuration and combined with single dish data from the
NRAO Green Bank Telescope.
The HI spectral line data have an angular resolution of 1' with rms
noise of 2K of brightness temperature, Tb, in each 0.83km/s velocity
channel.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 20 748 Inner Galaxy HI terminal velocity curve
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See also:
VIII/76 : Leiden/Argentine/Bonn (LAB) Survey of Galactic HI (Kalberla+ 2005)
J/ApJ/816/42 : Mass models for the Milky Way (McGaugh, 2016)
J/ApJ/783/130 : Parallaxes of high mass star forming regions (Reid+, 2014)
J/ApJS/140/331 : High-velocity HI observations at 21cm (Lockman+, 2002)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 6 F6.3 deg GLON [18.4/67] Galactic longitude in decimal degrees
8- 13 F6.2 km/s vLSR [18.7/134.2] Measured HI terminal velocities
15- 20 F6.2 km/s vMOD [27.7/138] Predicted HI terminal velocities (1)
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Note (1): Predicted HI terminal velocities from the linear rotation curve
fit, Σ(R)/Σ0=0.171(R/R0)+0.889; see also Figure 5.
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History:
From electronic version of the journal
References:
McClure-Griffiths et al. Paper I. 2007ApJ...671..427M 2007ApJ...671..427M
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 03-Feb-2017