J/MNRAS/521/2087 Reduced proper motion with Gaia DR3 (Viswanathan+, 2023)
Hidden deep in the halo: selection of a reduced proper motion halo
catalogue and mining retrograde streams in the velocity space.
Viswanathan A., Starkenburg E., Koppelman H., Helmi A., Balbinot E.,
Esselink A.F.
<Mon. Not. R. Astron. Soc. 521, 2087-2102 (2023)>
=2023MNRAS.521.2087V 2023MNRAS.521.2087V (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Associations, stellar ; Stars, distances ;
Abundances, [Fe/H] ; Radial velocities ; Optical
Keywords: methods: data analysis - catalogues - Galaxy: evolution -
Galaxy: halo - Galaxy: kinematics and dynamics - Galaxy: structure
Abstract:
With the advent of the European Space Agency's Gaia mission and its
recent data releases EDR3 and DR3, the astronomy community has
obtained the largest-ever cartograph of our Milky Way galaxy with
unprecedented astrometric parameters. In this paper, we have presented
a catalogue of ∼47 million halo stars on the main sequence with high
tangential velocity selected only using Gaia DR3 proper motions and
photometry. This is made possible using the reduced proper motion that
when plotted versus Gaia colours mimics the colour-magnitude diagram
for populations with different tangential velocities. The distance
makes up an important aspect of the 6D information often used in the
study of the dynamical evolution of the Milky Way halo. Here, we
calculate photometric distances to these stars with simple linear
colour-magnitude relation for these stars on the main sequence. The
typical uncertainty on these derived photometric distances is ∼7%
which is more reliable and probes farther away than would be possible
using Gaia parallaxes. Using the colour range 0.45<(G-GRP)<0.715
where the main sequence is narrower, gives an even better accuracy
down to 0.39kpc in distance.
The distribution of these sources in the sky, together with their
tangential component velocities, are very well-suited to study
retrograde substructures. We explore the selection of two complex
retrograde streams: GD-1 and Jhelum. For these streams, we resolve the
gaps, wiggles and density breaks reported in the literature more
clearly and also derive metallicity dependent distances. We also
illustrate the effect of the kinematic selection bias towards high
proper motion stars and incompleteness at larger distances due to
Gaia's scanning law. These examples showcase how the full RPM
catalogue made available here can help us paint a more detailed
picture of the build-up of the Milky Way halo. It is a golden age to
do Galactic Archaeology.
Such a main sequence stars sample with the largest halo cartograph in
the era of Gaia can also be used to provide spectroscopic targets to
the next big spectroscopic surveys such as WEAVE, 4MOST, and SDSS-V
because this catalogue complements the Gaia DR3 source spectra at the
fainter end. Even low-resolution spectroscopic follow-up that can
provide us with the missing line-of-sight velocities and/or
metallicities can be extremely useful to disentangle the merger
history of the inner stellar halo.
Description:
The tables consist of the following columns:
DR3/EDR3 source_ids of sources that are identified as Main Sequence
halo stars in the RPM diagram, positions in equatorial coordinates
(RA, Dec in degrees), the reduced proper motion parameter (Hg in mag),
extinction parameters (Av in mag, and the extinction fraction - no
unit), and the derived photometric distance and its uncertainty in
kpc. The stream member candidate catalogues (+ radial velocity
catalogues) have the same column along with metallicity dependent
distance and its uncertainty (upper and lower sigma) - all in kpc,
radial velocity and its uncertainty from SEGUE SDSS in km/s, where
available.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
rpmgaia3.dat 172 47650376 Full reduced proper motion halo catalogue
gd-1.dat 226 1155 Member candidates of the stellar stream GD-1
gd-1-rv.dat 244 58 Member candidates of the stellar stream GD-1
with radial velocities from SDSS SEGUE
jhelum.dat 225 1354 Member candidates of the stellar stream Jhelum
sgr.dat 225 1114 Member candidates of part of the stellar stream
Sagittarius
sgr-rv.dat 243 10 Member candidates of part of the stellar stream
Sagittarius with radial velocities from
SDSS SEGUE
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See also:
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
Byte-by-byte Description of file: rpmgaia3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 I19 --- GaiaDR3 Gaia DR3 source_id
21- 41 E21.18 deg RAdeg Right ascension (ICRS) at Ep=2016.0
43- 64 E22.18 deg DEdeg Declination (ICRS) at Ep=2016.0
66- 83 F18.15 mag HG Gaia G-band reduced proper motion
85-105 F21.19 mag Av Extinction
107-128 F22.18 --- Next Extinction fraction
130-150 F21.18 kpc Distph Photometric distance
152-172 E21.19 kpc e_Distph Photometric distance error
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Byte-by-byte Description of file: gd-1.dat jhelum.dat sgr.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 I19 --- GaiaDR3 Gaia DR3 source_id
21- 41 F21.17 deg RAdeg Right ascension (ICRS) at Ep=2016.0
43- 63 F21.17 deg DEdeg Declination (ICRS) at Ep=2016.0
65- 82 F18.15 mag HG Gaia G-band reduced proper motion
84-103 F20.18 mag Av Extinction
105-122 F18.16 --- Next Extinction fraction
124-143 F20.16 kpc Distph Photometric distance
145-163 F19.17 kpc e_Distph Photometric distance error
165-184 F20.16 kpc Dist[Fe/H] ? Metallicity dependent distance from [Fe/H]
187-205 F19.16 kpc E_Dist[Fe/H] ? Error on Dist[Fe/H] (upper value)
207-226 F20.17 kpc e_Dist[Fe/H] ? Error on Dist[Fe/H] (lower value)
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Byte-by-byte Description of file: gd-1-rv.dat sgr-rv.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 I19 --- GaiaDR3 Gaia DR3 source_id
21- 39 F19.15 deg RAdeg Right ascension (ICRS) at Ep=2016.0
41- 61 F21.17 deg DEdeg Declination (ICRS) at Ep=2016.0
63- 80 F18.15 mag HG Gaia G-band reduced proper motion
82-101 F20.18 mag Av Extinction
103-120 F18.16 --- Next Extinction fraction
122-140 F19.16 kpc Distph Photometric distance
142-160 F19.17 kpc e_Distph Photometric distance error
162-180 F19.16 kpc Dist[Fe/H] ? Metallicity dependent distance from [Fe/H]
183-200 F18.16 kpc E_Dist[Fe/H] ? Error on Dist[Fe/H] (upper value)
202-221 F20.17 kpc e_Dist[Fe/H] ? Error on Dist[Fe/H] (lower value)
223-233 F11.6 km/s RV Radial velocity from SDSS SEGUE
235-244 F10.7 km/s e_RV Radial velocity from SDSS SEGUE error
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Acknowledgements:
Akshara Viswanathan, viswanathan(at)astro.rug.nl
(End) Patricia Vannier [CDS] 16-Feb-2023