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Title: Butterfly in a Cocoon, Understanding the Origin and Morphology of Globular Cluster Streams: The Case of GD-1

Abstract

Tidally disrupted globular cluster (GC) streams are usually observed, and therefore perceived, as narrow, linear, and one-dimensional structures in the 6D phase space. In this paper, we show that the GD-1 stellar stream, which is the tidal debris of a disrupted GC, possesses a secondary diffuse and extended stellar component (~100 pc wide) around it, detected at the >5σ 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 GC streams.

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3]; ORCiD logo [4];  [5]
  1. Stockholm Univ. (Sweden)
  2. Univ. de Strasbourg (France)
  3. Univ. of Toronto, ON (Canada)
  4. Univ. of Michigan, Ann Arbor, MI (United States)
  5. Stockholm Univ. (Sweden); The Nordic Inst. for Theoretical Physics (NORDITA), Stockholm (Sweden); Univ. of Michigan, Ann Arbor, MI (United States)
Publication Date:
Research Org.:
Univ. of Michigan, Ann Arbor, MI (United States)
Sponsoring Org.:
USDOE Office of Science (SC); Swedish Research Council (VR); Oskar Klein Centre for Cosmoparticle Physics; Leinweber Center for Theoretical Physics; National Aeronautics and Space Administration (NASA); National Development and Reform Commission; Alfred P. Sloan Foundation; National Science Foundation (NSF)
OSTI Identifier:
1610970
Grant/Contract Number:  
SC0007859; 638-2013-8993; NNX15AK79G
Resource Type:
Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 881; Journal Issue: 2; Journal ID: ISSN 1538-4357
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; Astronomy & Astrophysics; Galaxy: formation; Galaxy: halo; Galaxy: structure; globular clusters: general; stars: kinematics and dynamics

Citation Formats

Malhan, Khyati, Ibata, Rodrigo A., Carlberg, Raymond G., Valluri, Monica, and Freese, Katherine. Butterfly in a Cocoon, Understanding the Origin and Morphology of Globular Cluster Streams: The Case of GD-1. United States: N. p., 2019. Web. https://doi.org/10.3847/1538-4357/ab2e07.
Malhan, Khyati, Ibata, Rodrigo A., Carlberg, Raymond G., Valluri, Monica, & Freese, Katherine. Butterfly in a Cocoon, Understanding the Origin and Morphology of Globular Cluster Streams: The Case of GD-1. United States. https://doi.org/10.3847/1538-4357/ab2e07
Malhan, Khyati, Ibata, Rodrigo A., Carlberg, Raymond G., Valluri, Monica, and Freese, Katherine. Tue . "Butterfly in a Cocoon, Understanding the Origin and Morphology of Globular Cluster Streams: The Case of GD-1". United States. https://doi.org/10.3847/1538-4357/ab2e07. https://www.osti.gov/servlets/purl/1610970.
@article{osti_1610970,
title = {Butterfly in a Cocoon, Understanding the Origin and Morphology of Globular Cluster Streams: The Case of GD-1},
author = {Malhan, Khyati and Ibata, Rodrigo A. and Carlberg, Raymond G. and Valluri, Monica and Freese, Katherine},
abstractNote = {Tidally disrupted globular cluster (GC) streams are usually observed, and therefore perceived, as narrow, linear, and one-dimensional structures in the 6D phase space. In this paper, we show that the GD-1 stellar stream, which is the tidal debris of a disrupted GC, possesses a secondary diffuse and extended stellar component (~100 pc wide) around it, detected at the >5σ 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 GC streams.},
doi = {10.3847/1538-4357/ab2e07},
journal = {The Astrophysical Journal (Online)},
number = 2,
volume = 881,
place = {United States},
year = {2019},
month = {8}
}

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Cited by: 7 works
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