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At a Crossroads: Stellar Streams in the South Galactic Cap

Grillmair, Carl J. (2017) At a Crossroads: Stellar Streams in the South Galactic Cap. Astrophysical Journal, 847 (2). Art. No. 119. ISSN 1538-4357. doi:10.3847/1538-4357/aa8872.

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We examine the distribution of old, metal-poor stars in a portion of the recently released PanSTARRs survey. We find an interesting confluence of four new cold stellar stream candidates that appear to converge on or pass near the south Galactic pole. The stream candidates, which we designate as Murrumbidgee, Molonglo, Orinoco, and Kwando, lie at a distance of ≈20 kpc and range in length from 13° to 95°, or about 5 to 33 kpc. The stream candidates are between 100 and 300 pc in width and are estimated to contain between 3000 and 8000 stars each, suggesting progenitors similar to modern day globular clusters. The trajectories of the streams imply orbits that range from hyperbolic to nearly circular. The Molonglo stream is nearly parallel to, at the same distance as, and offset by only 2.°5 from the previously discovered ATLAS stream, suggesting a possible common origin. Orinoco and Kwando also have similarly shaped, moderately eccentric, obliquely viewed orbits that suggest distinct progenitors within a common, larger parent body.

Item Type:Article
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URLURL TypeDescription Paper
Grillmair, Carl J.0000-0003-4072-169X
Additional Information:© 2017 The American Astronomical Society. Received 2017 July 28; revised 2017 August 14; accepted 2017 August 22; published 2017 September 28. We are very grateful to B. Shiao and R. White of the Space Telescope Science Institute for their assistance in optimizing PS-1 database queries. We also thank an anonymous referee for several useful recommendations. The Pan-STARRS1 Surveys (PS1) have been made possible through contributions of the Institute for Astronomy, the University of Hawaii, the Pan-STARRS Project Office, the Max-Planck Society and its participating institutes, the Max Planck Institute for Astronomy, Heidelberg and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns Hopkins University, Durham University, the University of Edinburgh, Queen's University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Las Cumbres Observatory Global Telescope Network Incorporated, the National Central University of Taiwan, the Space Telescope Science Institute, the National Aeronautics and Space Administration under Grant No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate, the National Science Foundation under Grant No. AST-1238877, the University of Maryland, and Eotvos Lorand University (ELTE). Facility: PS1.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Subject Keywords:Galaxy: halo; Galaxy: stellar content; Galaxy: structure; globular clusters: general
Issue or Number:2
Record Number:CaltechAUTHORS:20170929-083050550
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Official Citation:Carl J. Grillmair 2017 ApJ 847 119
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:81913
Deposited By: Tony Diaz
Deposited On:29 Sep 2017 16:47
Last Modified:15 Nov 2021 19:47

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