Measurement of Substructure from the Kinematics of the GD-1 Stellar Stream

Abstract

Stellar streams are sensitive tracers of low-mass dark matter subhalos and provide a means to test the Cold Dark Matter (CDM) paradigm on small scales. In this work, we connect the intrinsic velocity dispersion of the GD-1 stream to the number density and internal structure of dark matter subhalos in the mass range $10^5$-$10^9{M}_{\odot }$. We measure the radial velocity dispersion of GD-1 based on 160 identified member stars across four different spectroscopic catalogs. We use repeat observations of the same stars to constrain binarity. We find that the stream's intrinsic radial velocity dispersion ranges from approximately $2$-$5\text{km}{\text{s}}^{-1}$ across its length. The region of GD-1 with the highest velocity dispersion represents a $4\sigma$ deviation from unperturbed stream models formed in a smooth Milky Way potential, which are substantially colder. We use perturbation theory to model the stream's velocity dispersion as a function of dark matter subhalo population parameters, including the number of low-mass subhalos in the Milky Way, the dark matter half-mode mass, and the mass-concentration relation of subhalos. We find that the observed velocity dispersion can be explained by numerous impacts with low-mass dark matter subhalos, or by a single impact with a very compact subhalo with $M\gtrsim 10^8{M}_{\odot }$. Our constraint on the fraction of mass in subhalos is $f_{\mathrm{sub}}=0.05_{-0.03}^{+0.08}$ (68\% confidence). In both scenarios, our model prefers subhalos that are more compact compared to CDM mass-size expectations. These results suggest a possible deviation from CDM at low subhalo masses.

arXiv comment20 pages, 12 figures. Accepted for publication in ApJ

References in corpus (71)

• A Universal Density Profile from Hierarchical Clustering
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• LSST: from Science Drivers to Reference Design and Anticipated Data Products
• Dark Matter Substructure in Galactic Halos
• Where are the missing galactic satellites?
• Profiles of dark haloes: evolution, scatter, and environment
• Observational evidence for self-interacting cold dark matter
• The Aquarius Project: the subhalos of galactic halos
• The Ninth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon Oscillation Spectroscopic Survey
• Sterile Neutrinos as Dark Matter
• Halo Formation in Warm Dark Matter Models
• The mass distribution and gravitational potential of the Milky Way
• Cold dark matter haloes in the Planck era: evolution of structural parameters for Einasto and NFW profiles
• Clumps and streams in the local dark matter distribution
• The subhalo populations of LCDM dark haloes
• Cuspy No More: How Outflows Affect the Central Dark Matter and Baryon Distribution in Lambda CDM Galaxies
• Direct Detection of CDM Substructure
• Evidence for substructure in lens galaxies?
• The properties of warm dark matter haloes
• Constraining the Milky Way potential with a 6-D phase-space map of the GD-1 stellar stream
• Not so lumpy after all: modeling the depletion of dark matter subhalos by Milky Way-like galaxies
• The Early Data Release of the Dark Energy Spectroscopic Instrument
• Detection of a 63 Degree Cold Stellar Stream in the Sloan Digital Sky Survey
• Atomic Dark Matter
• Uncovering CDM halo substructure with tidal streams
• The Local Group on FIRE: Dwarf galaxy populations across a suite of hydrodynamic simulations
• How Lumpy is the Milky Way's Dark Matter Halo?
• The wide-field, multiplexed, spectroscopic facility WEAVE: Survey design, overview, and simulated implementation
• Milky Way Satellite Census. II. Galaxy--Halo Connection Constraints Including the Impact of the Large Magellanic Cloud
• The Spur and the Gap in GD-1: Dynamical evidence for a dark substructure in the Milky Way halo
• Clumpy Streams from Clumpy Halos: Detecting Missing Satellites with Cold Stellar Structures
• Characterization of subhalo structural properties and implications for dark matter annihilation signals
• The number and size of subhalo-induced gaps in stellar streams
• Dark Matter Sub-Halo Counts via Star Stream Crossings
• PeTar: a high-performance N-body code for modeling massive collisional stellar systems
• Stellar Multiplicity Meets Stellar Evolution And Metallicity: The APOGEE View
• Baryonic impact on the dark matter distribution in Milky Way-size galaxies and their satellites
• Linear perturbation theory for tidal streams and the small-scale CDM power spectrum
• Novel constraints on the particle nature of dark matter from stellar streams
• The Southern Stellar Stream Spectroscopic Survey ($S^5$): Overview, Target Selection, Data Reduction, Validation, and Early Science
• Discovery and Characterization of 3000+ Main-Sequence Binaries from APOGEE Spectra
• Dark Matter Constraints from a Unified Analysis of Strong Gravitational Lenses and Milky Way Satellite Galaxies
• Forensics of Subhalo-Stream Encounters: The Three Phases of Gap Growth
• Generation of mock tidal streams
• Star Stream Folding by Dark Galactic Sub-Halos
• The statistics of the subhalo abundance of dark matter haloes
• Evidence of a population of dark subhalos from Gaia and Pan-STARRS observations of the GD-1 stream
• Dynamics of stream-subhalo interactions
• A supra-massive population of stellar-mass black holes in the globular cluster Palomar 5
• Modeling the Impact of Baryons on Subhalo Populations with Machine Learning
• Constraints on the mass-concentration relation of cold dark matter halos with 11 strong gravitational lenses
• Butterfly in a Cocoon, Understanding the origin and morphology of Globular Cluster Streams: The case of GD-1
• Modeling dark matter subhalos in a constrained galaxy: Global mass and boosted annihilation profiles
• Symphony: Cosmological Zoom-in Simulation Suites over Four Decades of Host Halo Mass
• High-resolution spectroscopy of the GD-1 stellar stream localizes the perturber near the orbital plane of Sagittarius
• A deeper look at the GD1 stream: density variations and wiggles
• Searching for the GD-1 Stream Progenitor in Gaia DR2 with Direct N-body Simulations
• DESI Early Data Release Milky Way Survey Value-Added Catalogue
• Velocity Dispersion of the GD-1 Stellar Stream
• The impact of a massive Sagittarius dSph on GD-1-like streams
• Improved particle spray algorithm for modeling globular cluster streams
• The dark side of FIRE: predicting the population of dark matter subhaloes around Milky Way-mass galaxies
• GD-1 Stellar Stream and Cocoon in the DESI Early Data Release
• A million-solar-mass object detected at cosmological distance using gravitational imaging
• Member stars of the GD1 tidal stream from the SDSS, LAMOST and Gaia surveys
• SIDM Concerto: Compilation and Data Release of Self-interacting Dark Matter Zoom-in Simulations
• LMC-driven anisotropic boosts in stream--subhalo interactions
• Massive prompt cusps: A new signature of warm dark matter
• A possible challenge for Cold and Warm Dark Matter
• Inferring the density and membership of stellar streams with flexible models: The GD-1 stream in Gaia Data Release 3
• Semi-Analytic Modeling of Dark Matter Subhalo Encounters with Thin Stellar Streams: Statistical Predictions for GD-1-like Streams in CDM

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