J/A+A/635/L3 Candidate member stars of the Sagittarius stream (Antoja+, 2020)
An all-sky proper-motion map of the Sagittarius stream using Gaia DR2.
Antoja T., Ramos P., Mateu C., Helmi A., Anders F., Jordi C.,
Carballo-Bello J.
<Astron. Astrophys. 635, L3 (2020)>
=2020A&A...635L...3A 2020A&A...635L...3A (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby; Proper motions; Positional data ; Photometry
Keywords: Galaxy: halo - Galaxies: dwarf - Galaxy: kinematics and dynamics -
Galaxy: formation - astrometry
Abstract:
We aim to measure the proper motion along the Sagittarius stream,
which is the missing piece in determining its full 6D phase space
coordinates. We conduct a blind search of over-densities in proper
motion from the Gaia second data release (DR2) in a broad region
around the Sagittarius stream by applying wavelet transform
techniques. We find that for most of the sky patches, the highest
intensity peaks delineate the path of the Sagittarius stream. The 1500
peaks identified depict a continuous sequence spanning almost 2pi in
the sky, only obscured when the stream crosses the Galactic disk.
Altogether, around 100000 stars potentially belong to the stream as
indicated by a coarse inspection of the color-magnitude diagrams. From
these stars, we determine the proper motion along the Sagittarius
stream, making it the proper-motion sequence with the largest span and
continuity ever measured for a stream. A first comparison with
existing N-body models of the stream reveals some discrepancies,
especially near the pericenter of the trailing arm and an
underestimation of the total proper motion for the leading arm. Our
study provides a starting point for determining the variation of the
population of stars along the stream, the distance to the stream from
the red clump stars, and the solar motion. It also permits much more
accurate measurement of the Milky Way potential.
Description:
This is a list of 294344 candidate member stars of the Sagittarius
stream and dwarf in the range -120°<Lambda<150°, i.e. avoiding
the region of the Galactic plane. These members have been selected
only based on proper motions from Gaia DR2 and a certain fraction of
contamination is expected. For each stars source_id, equatorial
coordinates, proper motions in equatorial system, magnitude and color
from Gaia DR2 are given. More material (coordinates and proper motions
of member candidates in different reference systems, median proper
motions as a function of Lambda, interpolation used to obtain smooth
curves given as a Python pickle, animations) are available at:
https://services.fqa.ub.edu/sagittarius
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablee1.dat 114 294344 Candidate member stars of the Sagittarius stream
(corrected version, 04-Feb-2021)
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
Byte-by-byte Description of file: tablee1.dat
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Bytes Format Units Label Explanations
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1- 19 I19 --- Source Gaia DR2 Unique source identifier (source_id)
21- 38 F18.14 deg RAdeg Right ascension (ICRS) at Ep=2015.5
40- 57 F18.14 deg DEdeg Declination (ICRS) at Ep=2015.5
59- 75 F17.14 mas/yr pmRA Proper motion in right ascension direction,
pmRA*cosDE (J2015.5)
77- 93 F17.14 mas/yr pmDE Proper motion in declination direction
(J2015.5)
95-103 F9.6 mag Gmag G-band mean magnitude (photgmean_mag)
105-114 F10.7 mag B-R BP - RP colour (bp_rp)
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Acknowledgements:
Please cite the reference publication 2020A&A...635L...3A 2020A&A...635L...3A and use the
following acknowledgement:
"This work has made use of data from the European Space Agency (ESA)
mission Gaia(https://www.cosmos.esa.int/gaia), processed by the Gaia
Data Processing and Analysis Consortium (DPAC,
https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the
DPAC has been provided by national institutions, in particular the
institutions participating in the Gaia Multilateral Agreement."
From Teresa Antoja, tantoja(at)fqa.ub.edu
Pau Ramos, pramos(at)fqa.ub.edu
Cecilia Mateu, cmateu(at)fisica.edu.uy
History:
04-Mar-2020: on-line version
04-Feb-2021: corrected version, from author
(End) Teresa Antoja [ICCUB, Barcelona], Patricia Vannier [CDS] 24-Feb-2020