Butterfly in a Cocoon, Understanding the origin and morphology of Globular Cluster Streams: The case of GD-1

Abstract

Tidally disrupted globular cluster streams are usually observed, and therefore perceived, as narrow, linear and one-dimensional structures in the 6D phase-space. Here we show that the GD-1 stellar stream ($\approx$ 30 pc wide), which is the tidal debris of a disrupted globular cluster, possesses a secondary diffuse and extended stellar component ($\approx$ 100 pc wide) around it, detected at >5$\sigma$ confidence level. Similar morphological properties are seen in synthetic streams that are produced from star clusters that are formed within dark matter sub-halos and then accrete onto a massive host galaxy. This lends credence to the idea that the progenitor of the highly retrograde GD-1 stream was originally formed outside of the Milky Way in a now defunct dark satellite galaxy. We deem that in future studies, this newly found $cocoon$ component may serve as a structural hallmark to distinguish between the in-situ and ex-situ (accreted) formed globular cluster streams.

11 pages, 10 figures, accepted for publication in The Astrophysical Journal

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Cited by in corpus (43)

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• galstreams: A Library of Milky Way Stellar Stream Footprints and Tracks
• Evidence of a population of dark subhalos from Gaia and Pan-STARRS observations of the GD-1 stream
• Broken into Pieces: ATLAS and Aliqa Uma as One Single Stream
• An all-sky proper motion map of the Sagittarius stream using Gaia DR2
• A stellar stream remnant of a globular cluster below the metallicity floor
• Probing the nature of dark matter with accreted globular cluster streams
• High-resolution spectroscopy of the GD-1 stellar stream localizes the perturber near the orbital plane of Sagittarius
• Detection of Strong Epicyclic Density Spikes in the GD-1 Stellar Stream. An Absence of Evidence for the Influence of Dark Matter Subhalos?
• A closer look at the spur, blob, wiggle, and gaps in GD-1
• Uncovering a 260 pc wide, 35 Myr old filamentary relic of star formation
• The Pristine survey -- XVI. The metallicity of 26 stellar streams around the Milky Way detected with the STREAMFINDER in Gaia EDR3
• The Density Structure of Simulated Stellar Streams
• Exploring the outskirts of globular clusters: the peculiar kinematics of NGC 3201
• Faint objects in motion: the new frontier of high precision astrometry
• Phase-space correlation in stellar streams of the Milky Way halo: The clash of Kshir and GD-1
• Purveyors of fine halos. II. Chemodynamical association of halo stars with Milky Way globular clusters
• The hidden past of M92: Detection and characterization of a newly formed 17° long stellar stream using the Canada-France Imaging Survey
• The impact of a massive Sagittarius dSph on GD-1-like streams
• The oblateness of the Milky Way dark matter halo from the stellar streams of NGC 3201, M68, and Palomar 5
• A chemo-dynamical link between the Gjöll stream and NGC 3201
• The structure of accreted stellar streams
• $S^5$: The destruction of a bright dwarf galaxy as revealed by the chemistry of the Indus stellar stream
• GD-1 Stellar Stream and Cocoon in the DESI Early Data Release
• NGC 1261: an $r$-process enhanced globular cluster from the Gaia-Enceladus event
• Probability of forming gaps in the GD-1 stream by close encounters of globular clusters
• New constraints on the dark matter density profiles of dwarf galaxies from proper motions of globular cluster streams
• Ironing the folds: The phase space chevrons of a GSE-like merger as a dark matter subhalo detector
• LMC-driven anisotropic boosts in stream--subhalo interactions
• 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
• Uniform Modelling of the Stellar Density of Thirteen Tidal Streams within the Galactic Halo
• ESA Voyage 2050 white paper -- Faint objects in motion: the new frontier of high precision astrometry
• Modelling the Track of the GD-1 Stellar Stream Inside a Host with a Fermionic Dark Matter Core-Halo Distribution
• Weakly-Supervised Anomaly Detection in the Milky Way
• The Pristine survey: XXVII. The extremely metal-poor stream C-19 stretches over more than 100 degrees
• Measurement of Substructure from the Kinematics of the GD-1 Stellar Stream
• StarStream: Automatic detection algorithm for stellar streams
• Segue 2 Recently Collided with the Cetus-Palca Stream: New Opportunities to Constrain Dark Matter in an Ultra-Faint Dwarf
• Towards characterizing dark matter subhalo perturbations in stellar streams with graph neural networks
• No Stream Left Unscathed: The imprint of a host galaxy