GD-1: the relic of an old metal-poor globular cluster

Abstract

Combining data from Gaia DR2, SDSS DR14 and LAMOST DR6, we update the fit to model of the properties of the stellar stream GD-1 and find that it has an age of $\sim 13$ Gyr, [Fe/H] of $-2.2\pm 0.12$, and a distance from the sun of $\sim 8$ kpc. We tabulate 6D phase-space fiducial points along the GD-1 stream orbit over a 90${}^{\circ }$ arc. The fitted orbit shows that the stream has an eccentricity $e\sim 0.3$, perigalacticon of 14.2 kpc, apogalacticon of 27.0 kpc and inclination $i\sim 40^{\circ }$. There is evidence along the arc for 4 candidate stellar overdensities, one candidate gap, two candidate stellar underdensities and is cut off at ${\varphi }_1\sim 2^{\circ }$ (in the stream-aligned $({\varphi }_1,{\varphi }_2)$ coordinate system of \citet{kop10}). The spur originating at ${\varphi }_1\sim -40^{\circ }$ implies stars were pulled away from the stream trace by an encounter (potentially a dark matter subhalo). The narrowest place ( FWHM $\sim 44.6$ pc) of the GD-1 trace is at $({\varphi }_1,{\varphi }_2^c)\sim (-14^{\circ },0.15^{\circ })$, which is $\sim (178.18^{\circ },52.19^{\circ })$ in (R. A., Decl.), where the progenitor is possibly located. We also find six BHB and 10 BS spectroscopic stars in the GD-1 stream.

21 pages, 16 figures, 8 tables

References in corpus (24)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• Gaia Data Release 2. Summary of the contents and survey properties
• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• Gaia Data Release 2: The astrometric solution
• The Dartmouth Stellar Evolution Database
• galpy: A Python Library for Galactic Dynamics
• SEGUE: A Spectroscopic Survey of 240,000 stars with g=14-20
• ULySS: A Full Spectrum Fitting Package
• Constraining the Milky Way potential with a 6-D phase-space map of the GD-1 stellar stream
• Detection of a 63 Degree Cold Stellar Stream in the Sloan Digital Sky Survey
• Evidence for a systematic offset of -80 micro-arcseconds in the Gaia DR2 parallaxes
• The PASTEL catalogue of stellar parameters
• Automatic Determination of Stellar Atmospheric Parameters and Construction of Stellar Spectral Templates of the Guoshoujing Telescope (LAMOST)
• Coude-feed stellar spectral library - atmospheric parameters
• Spectroscopic ages and metallicities of stellar populations: validation of full spectrum fitting
• The shape of the inner Milky Way halo from observations of the Pal 5 and GD-1 stellar streams
• Off the beaten path: Gaia reveals GD-1 stars outside of the main stream
• Dynamical modeling of tidal streams
• Dipping Our Toes in the Water: First Models of GD-1 as a Stream
• Gaps in the GD-1 Star Stream
• An Orbit Fit for the Grillmair Dionatos Cold Stellar Stream
• A deeper look at the GD1 stream: density variations and wiggles
• Modeling GD-1 Gaps in a Milky-Way Potential
• Validation of LAMOST Stellar Parameters with the PASTEL Catalog

Cited by in corpus (6)

• Galactic potential constraints from clustering in action space of combined stellar stream data
• Formation imprints in the kinematics of the Milky Way globular cluster system
• GD-1 Stellar Stream and Cocoon in the DESI Early Data Release
• ED-2: a cold but not so narrow stellar stream crossing the Solar neighbourhood
• Evidence for C and Mg variations in the GD-1 stellar stream
• Uniform Modelling of the Stellar Density of Thirteen Tidal Streams within the Galactic Halo