J/A+A/674/A37 Gaia DR3. MW asymmetric disc mapping (Gaia Coll.+, 2023)
Gaia Data Release 3: Mapping the asymmetric disc of the Milky Way.
Gaia Collaboration, Drimmel R., Romero-Gomez M., Chemin L., Ramos P.,
Poggio E., Ripepi V., et al.
<Astron. Astrophys. 674, A37 (2023)>
=2023A&A...674..A37G (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way
Mission_Name: Gaia
Keywords: Galaxy: kinematics and dynamics - Galaxy: structure - Galaxy: disk -
Galaxy: bulge - catalogs
Abstract:
With the most recent Gaia data release the number of sources with
complete 6D phase space information (position and velocity) has
increased to well over 33 million stars, while stellar astrophysical
parameters are provided for more than 470 million sources, in addition
to the identification of over 11 million variable stars.
Using the astrophysical parameters and variability classifications
provided in Gaia DR3, we select various stellar populations to explore
and identify non-axisymmetric features in the disc of the Milky Way in
both configuration and velocity space.
Using more about 580 thousand sources identified as hot OB stars,
together with 988 known open clusters younger than 100 million years,
we map the spiral structure associated with star formation 4-5 kpc
from the Sun. We select over 2800 Classical Cepheids younger than 200
million years, which show spiral features extending as far as 10 kpc
from the Sun in the outer disc. We also identify more than 8.7 million
sources on the red giant branch (RGB), of which 5.7 million have
line-of-sight velocities, allowing the velocity field of the Milky Way
to be mapped as far as 8 kpc from the Sun, including the inner disc.
The spiral structure revealed by the young populations is consistent
with recent results using Gaia DR3 astrometry and source lists based
on NIR photometry, showing the Local (Orion) arm to be at least 8 kpc
long, and an outer arm consistent with what is seen in HI surveys,
which seems to be a continuation of the Perseus arm into the third
quadrant. Meanwhile, the subset of RGB stars with velocities clearly
reveals the large scale kinematic signature of the bar in the inner
disc, as well as evidence of streaming motions in the outer disc that
might be associated with spiral arms or bar resonances. A local
comparison of the velocity field of the OB stars reveals both
similarities and differences with the RGB sample. This cursory study
of Gaia DR3 data shows there is a rich bounty of kinematic information
to be explored more deeply, which will undoubtedly lead us to an
understanding of the dynamical nature of the Milky Way's
non-axisymmetric structures.
Description:
Table 1: Selected parameters for the Open Clusters
sample used in the paper.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 115 2531 Selected parameters for the open clusters sample
used in the paper
table2.dat 95 3306 Selected parameters for the classical Cepheid
sample used in the paper
vpob.dat 108 18 Velocity profiles of the OB stars
from Fig. 17 of the paper
vprgb.dat 108 68 Velocity profiles of the RGB stars
from Fig. 17 of the paper
list.dat 83 18 List of fits maps
fits/* . 18 Individual fits maps
--------------------------------------------------------------------------------
See also:
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- Cluster Cluster name
19- 25 F7.3 deg GLON Galactic longitude
27- 33 F7.3 deg GLAT Galactic latitude
35- 38 I4 --- Nmemb Number of members
40- 46 F7.3 mas/yr pmRA Median proper motion along RA
48- 53 F6.3 mas/yr e_pmRA Proper motion dispersion along RA
55- 61 F7.3 mas/yr pmDE Median proper motion along Dec
63- 68 F6.3 mas/yr e_pmDE Proper motion dispersion along Dec
70- 75 F6.3 mas Plx Median parallax
77- 81 F5.3 mas e_Plx Parallax dispersion
83- 91 F9.3 km/s RV ?=-1000 median radial velocity of members
93-101 F9.3 km/s e_RV ?=-1000 uncertainty on median radial velocity
103-106 I4 --- o_RV Number of stars used to compute medianRV
108-111 F4.2 [yr] Age Age of the cluster
113-115 I3 --- nmag0 Number of stars with absolute magnitude<0
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 I19 --- GaiaDR3 Gaia EDR3 identification source_id
21- 29 F9.5 deg GLON Galactic longitude
31- 39 F9.5 deg GLAT Galactic latitude
43- 47 F5.2 kpc Dist Distance
49- 54 F6.3 mag mu Distance modulus
57- 61 F5.3 mag e_mu Uncertainty on the distance modulus
63- 67 F5.2 [-] [Fe/H] Metallicity
69- 72 F4.2 [-] e_[Fe/H] Uncertainty on the metallicity
74 I1 --- Flag [0/1] Metallicity flag (1)
76- 83 A8 --- Ref Provenance of the classical Cepheid (2)
85- 89 F5.3 [Gyr] logAge Logarithm of the age
91- 95 F5.3 [Gyr] e_logAge Uncertainty on the logarithm of the age
--------------------------------------------------------------------------------
Note (1): Flag as follows:
0 = the metallicity was taken from Gaia DR3 astrophysical parameters
1 = the metallicity was calculated from the the metallicity gradient of the
Galactic disc (see text fro details)
Note (2): Provenance of the Classical Cepheid as follows:
Gaia_DR3 = the star is included in the Gaia DR3 vari_cepheids catalogue
P21 = objects taken from Pietrukowicz et al. (2021ApJ...914..127I 2021ApJ...914..127I) catalogue
Inno = objects taken from Inno et al. (2021AcA....71..205I 2021AcA....71..205I) catalogue
--------------------------------------------------------------------------------
Byte-by-byte Description of file: vpob.dat vprgb.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 F4.1 kpc Radius Galactocentric radius
7- 13 F7.3 km/s vphimin Azimuthal velocity at 16th percentile
16- 22 F7.3 km/s vphi Azimuthal velocity at 50th percentile
25- 31 F7.3 km/s vphimax Azimuthal velocity at 84th percentile
34- 39 F6.3 km/s sigvRmin Radial velocity dispersion at 16th percentile
42- 47 F6.3 km/s sigvR Radial velocity dispersion at 50th percentile
50- 55 F6.3 km/s sigvRmax Radial velocity dispersion at 84th percentile
58- 63 F6.3 km/s sigvphimin Azimuthal velocity dispersion
at 16th percentile
66- 71 F6.3 km/s sigvphi Azimuthal velocity dispersion
at 50th percentile
74- 79 F6.3 km/s sigvphimax Azimuthal velocity dispersion
at 84th percentile
82- 87 F6.3 km/s sigvZmin Vertical velocity dispersion
at 16th percentile
90- 95 F6.3 km/s sigvZ Vertical velocity dispersion
at 50th percentile
98-103 F6.3 km/s sigvZmax Vertical velocity dispersion
at 84th percentile
106-108 I3 ---- npix Number of pixel in the radial bin of the
velocity map
--------------------------------------------------------------------------------
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 Kibyte size Size of FITS file
5- 31 A27 --- FileName Name of FITS file, in subdirectory fits
33- 83 A51 --- Title Title of the FITS file
--------------------------------------------------------------------------------
Acknowledgements:
Vincenzo Ripepi, vincenzo.ripepi(at)inaf.it
Laurent Chemin, astro.chemin(at)gmail.com
(End) Patricia Vannier [CDS] 16-Jun-2022