J/other/RAA/18.146 Spiral structure of the Milky Way (Xu+, 2018)
The spiral structure of the Milky Way.
Xu Y., Hou L.-G., Wu Y.-W.
<Res. Astron. Astrophys., 18, 146 (2018)>
=2018RAA....18..146X 2018RAA....18..146X (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Masers ; Stars, O ; Proper motions ;
Parallaxes, trigonometric
Keywords: Galaxy: structure - Galaxy: kinematics and dynamics - masers -
techniques: high angular resolution - astrometry - stars: formation
Abstract:
The morphology and kinematics of the spiral structure of the Milky Way
are long-standing problems in astrophysics. In this review we firstly
summarize various methods with different tracers used to solve this
puzzle. The astrometry of Galactic sources is gradually alleviating
this difficult situation caused mainly by large distance
uncertainties, as we can currently obtain accurate parallaxes (a few
µas) and proper motions (∼1km/s) by using Very Long Baseline
Interferometry (VLBI). On the other hand, the Gaia mission is
providing the largest, uniform sample of parallaxes for O-type stars
in the entire Milky Way. Based upon the VLBI maser and Gaia O-star
parallax measurements, nearby spiral structures of the Perseus, Local,
Sagittarius and Scutum Arms are determined in unprecedented detail.
Meanwhile, we estimate fundamental Galactic parameters of the distance
to the Galactic center, R0, to be 8.35±0.18kpc, and circular
rotation speed at the Sun, {THETA}0, to be 240±10km/s. We found
kinematic differences between O stars and interstellar masers: the O
stars, on average, rotate faster, >8km/s than maser-traced high-mass
star forming regions.
Description:
We display the spiral structure revealed by O stars from Gaia DR2 and
VLBI maser parallax measurements. Collectively, 101 masers and 635 O
stars are listed in Tables 2 and 3 respectively.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 98 101 Parallaxes and proper motions of masers
table3.dat 212 635 Parallaxes and proper motions of O Stars
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
I/347 : Distances to 1.33 billion stars in Gaia DR2 (Bailer-Jones+, 2018)
J/A+A/616/L15 : Parallaxes and Proper Motions of OB stars (Xu+, 2018)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name Maser name
17- 25 F9.5 deg RAdeg Right ascension (J2000)
27- 35 F9.5 deg DEdeg Declination (J2000)
37- 41 F5.3 mas plx Parallax
43- 47 F5.3 mas e_plx rms uncertainty on plx
49- 53 F5.2 mas/yr pmRA Proper motion along RA (pmRA*cosDE)
55- 58 F4.2 mas/yr e_pmRA rms uncertainty on pmRA
60- 64 F5.2 mas/yr pmDE Proper motion along DE
66- 69 F4.2 mas/yr e_pmDE rms uncertainty on pmDE
71- 73 I3 km/s Vlsr LSR velocity
75- 76 I2 km/s e_Vlsr rms uncertainty on Vlsr
78- 80 A3 --- Arm Spiral arm in which it resides
82- 89 F8.4 deg GLON Galactic longitude
91- 98 F8.4 deg GLAT Galactic latitude
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name Star name
11- 23 F13.9 deg RAdeg Right ascension (ICRS) at epoch 2015.5
25- 37 F13.9 deg DEdeg Declination (ICRS) at epoch 2015.5
39- 49 F11.9 mas Plx Gaia DR2 Parallax
51- 61 F11.9 mas e_Plx rms uncertainty on Plx
63- 75 F13.9 mas/yr pmRA Gaia DR2 Proper motion along RA (pmRA*cosDE)
77- 87 F11.9 mas/yr e_pmRA rms uncertainty on pmRA
89-101 F13.9 mas/yr pmDE Gaia DR2 Proper motion along DE
103-113 F11.9 mas/yr e_pmDE rms uncertainty on pmDE
115-120 F6.1 km/s Vlsr ? LSR velocity
122-128 F7.3 km/s e_Vlsr ? rms uncertainty on Vlsr
130-151 A22 --- SpType Spectral type
153-165 F13.9 deg GLON Galactic longitude
167-179 F13.9 deg GLAT Galactic latitude
181-188 A8 --- --- [Gaia DR2]
190-208 I19 --- GaiaDR2 Gaia DR2 source number
210-212 A3 --- Arm Spiral arm in which it resides
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 06-Aug-2019