J/MNRAS/486/2995 GD-1 stellar stream (Malhan+, 2019)
Constraining the Milky Way halo potential with the GD-1 stellar stream.
Malhan K., Ibata R.A.
<Mon. Not. R. Astron. Soc., 486, 2995-3005 (2019)>
=2019MNRAS.486.2995M 2019MNRAS.486.2995M (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Photometry
Keywords: dark matter - Galaxy : halo - Galaxy: structure -
stars: kinematics and dynamics - Galaxy: fundamental parameters
Abstract:
We use ESA/Gaia astrometry together with SEGUE and LAMOST measurements
of the GD-1 stellar stream to explore the improvement on the Galactic
gravitational potential that these new data provide. Assuming a
realistic universal model for the dark matter halo together with
reasonable models of the baryonic components, we find that the orbital
solutions for GD-1 require the circular velocity at the Solar radius
to be Vcirc(R☉)=244±4km/s, and also that the density
flattening of the dark halo is qrho=0.82+0.25-0.13. The
corresponding Galactic mass within 20kpc was estimated to be
MMW(<20kpc)=2.5±0.2x1011M☉. Moreover, Gaia's excellent
proper motions also allowed us to constrain the velocity dispersion of
the GD-1 stream in the direction tangential to the line of sight to be
<2.30km/s (95% confidence limit), confirming the extremely cold
dynamical nature of this system.
Description:
GD-1 members were first recovered from our STREAMFINDER density map
that was obtained from processing the Gaia DR2 catalogue (Malhan &
Ibata, 2018MNRAS.477.4063M 2018MNRAS.477.4063M; Malhan et al., 2018MNRAS.481.3442M 2018MNRAS.481.3442M; Ibata
et al., 2019ApJ...872..152I 2019ApJ...872..152I). This GD-1 data set was then
cross-matched with the SEGUE and LAMOST data to acquire stellar vlos
and [Fe/H] information that is missing from Gaia DR2 (these stars are
listed in Table 2).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 67 97 GD-1 star members with measured line-of-sight
velocities from SEGUE and LAMOST
--------------------------------------------------------------------------------
See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.5 deg RAdeg Right ascension (J2000) (1)
11- 18 F8.5 deg DEdeg Declination (J2000) (1)
20- 24 F5.2 mag Gmag0 Extinction corrected Gaia magnitude G (2)
26- 29 F4.2 mag (GBP-GRP)0 Extinction corrected Gaia color GBP-GRP (2)
31- 37 F7.2 km/s Vlos Observed line of sight velocities
39- 43 F5.2 km/s e_Vlos Uncertainties in observed line of
sight velocities
45- 52 F8.2 [-] [Fe/H] ?=-9999 Observed metallicities
54- 61 F8.2 [-] e_[Fe/H] ?=-9999 Uncertainties in observed
metallicities
63- 65 A3 --- Source [LS- ] Whether source is from SDSS/SEGUE
or LAMOST survey
67 A1 --- Pmember [YN] Membership probability
--------------------------------------------------------------------------------
Note (1): from Gaia DR2 (2018, Cat. I/345).
Note (2): from Gaia DR2 (2018, Cat. I/345), corrected for extinction following
Ibata et al. (2019ApJ...872..152I 2019ApJ...872..152I).
--------------------------------------------------------------------------------
Acknowledgements:
Khyati Malhan, khyati.malhan(at)fysik.su.se
(End) Patricia Vannier [CDS] 03-Jul-2019