Velocity Dispersion of the GD-1 Stellar Stream

Abstract

Tidally dissolved globular clusters form thin stellar streams that preserve a historical record of their past evolution. We report a radial velocity dispersion of $2.3\pm 0.3\text{km}{\text{s}}^{-1}$ in the GD-1 stellar stream using a sample of 43 spectroscopically confirmed members. The GD-1 velocity dispersion is constant over the surveyed $\approx 15^{\circ }$ span of the stream. We also measured velocity dispersion in the spur adjacent to the main GD-1 stream, and found a similar value at the tip of the spur. Surprisingly, the region of the spur closer to the stream appears dynamically colder than the main stream. An unperturbed model of the GD-1 stream has a velocity dispersion of $\approx 0.6\text{km}{\text{s}}^{-1}$, indicating that GD-1 has undergone dynamical heating. Stellar streams arising from globular clusters, which prior to their arrival in the Milky Way, orbited a dwarf galaxy with a cored density profile are expected to have experienced the amount of heating required to match the velocity dispersion observed in GD-1. This suggests that GD-1 has been accreted and that imprints of its original host galaxy, including the inner slope of its dark-matter halo, remain observable in the stream today.

submitted to AAS Journals

References in corpus (11)

• The NumPy array: a structure for efficient numerical computation
• Ultralight scalars as cosmological dark matter
• The DESI Experiment Part I: Science,Targeting, and Survey Design
• The Kinematics of the Ultra-Faint Milky Way Satellites: Solving the Missing Satellite Problem
• Evidence from the H3 Survey that the Stellar Halo is Entirely Comprised of Substructure
• Detection of a 63 Degree Cold Stellar Stream in the Sloan Digital Sky Survey
• Timing the Early Assembly of the Milky Way with the H3 Survey
• SDSS-V: Pioneering Panoptic Spectroscopy
• Generation of mock tidal streams
• Milky Way Mass and Potential Recovery Using Tidal Streams in a Realistic Halo
• Palomar 5 and its Tidal Tails: A Search for New Members in the Tidal Stream

Cited by in corpus (18)

• galstreams: A Library of Milky Way Stellar Stream Footprints and Tracks
• The impact of a massive Sagittarius dSph on GD-1-like streams
• The Pristine survey -- XVII. The C-19 stream is dynamically hot and more extended than previously thought
• The Pristine survey XVIII: C-19: Tidal debris of a dark matter-dominated globular cluster?
• Disconnecting the Dots: Re-Examining the Nature of Stellar "Strings" in the Milky Way
• GD-1 Stellar Stream and Cocoon in the DESI Early Data Release
• The Extended Tidal Tails of NGC 7089 (M2)
• New constraints on the dark matter density profiles of dwarf galaxies from proper motions of globular cluster streams
• Variation in the Stellar Mass Function Along Stellar Streams
• Characterization and dynamics of the peculiar stream Jhelum, A tentative role for the Sagittarius dwarf galaxy
• Mass classification of dark matter perturbers of stellar tidal streams
• Modelling the Track of the GD-1 Stellar Stream Inside a Host with a Fermionic Dark Matter Core-Halo Distribution
• Measuring the Sun's velocity using Gaia EDR3 observations of Stellar Streams
• Elongated Gravity Sources as an Analytical Limit for Flat Galaxy Rotation Curves
• Measurement of Substructure from the Kinematics of the GD-1 Stellar Stream
• Inferring the density and membership of stellar streams with flexible models: The GD-1 stream in Gaia Data Release 3
• Towards characterizing dark matter subhalo perturbations in stellar streams with graph neural networks
• Identification of a dwarf galaxy stream in Gaia, and its possible association with the VPOS structure