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. =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 V_circ_(R_{sun}_)=244+/-4km/s, and also that the density flattening of the dark halo is q_rho_=0.82^+0.25^_-0.13_. The corresponding Galactic mass within 20kpc was estimated to be M_MW_(<20kpc)=2.5+/-0.2x10^11^M_{sun}_. 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; Malhan et al., 2018MNRAS.481.3442M; Ibata et al., 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). -------------------------------------------------------------------------------- Acknowledgements: Khyati Malhan, khyati.malhan(at)fysik.su.se ================================================================================ (End) Patricia Vannier [CDS] 03-Jul-2019