Smash 1: a very faint globular cluster disrupting in the outer reaches of the lMC?

Journal Article · Mon Oct 10 00:00:00 EDT 2016 · Astrophysical Journal Letters

DOI:https://doi.org/10.3847/2041-8205/830/1/L10· OSTI ID:22868615

Martin, Nicolas F.; Jungbluth, Valentin ^[1]; Nidever, David L. ^[2]; Bell, Eric F. ^[3]; Besla, Gurtina ^[4]; Blum, Robert D. ^[5]; Cioni, Maria-Rosa L. ^[6]; Conn, Blair C. ^[7]; Kaleida, Catherine C. ^[8]; Gallart, Carme ^[9]; Jin, Shoko ^[10]; Majewski, Steven R. ^[11]; Martinez-Delgado, David ^[12]; others, and

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1. Observatoire Astronomique de Strasbourg, Université de Strasbourg, CNRS, UMR 7550, 11 rue de l’Université, F-67000 Strasbourg (France)
2. Large Synoptic Survey Telescope, 950 North Cherry Avenue, Tucson, AZ 85719 (United States)
3. Department of Astronomy, University of Michigan, 1085 S. University Avenue, Ann Arbor, MI 48109-1107 (United States)
4. Department of Astronomy, University of Arizona, AZ 85721-0065 (United States)
5. National Optical Astronomy Observatory, 950 N Cherry Avenue, Tucson, AZ 85719 (United States)
6. Universität Potsdam, Institut für Physik und Astronomie, Karl-Liebknecht-Str. 24/25, D-14476 Potsdam (Germany)
7. Research School of Astronomy and Astrophysics, The Australian National University, Mt Stromlo Observatory, via Cotter Road, Weston, ACT 2611 (Australia)
8. Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory, Casilla 603, La Serena (Chile)
9. Instituto de Astrofísica de Canarias, La Laguna, Tenerife (Spain)
10. Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, NL-9700AD Groningen (Netherlands)
11. Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States)
12. Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstr. 12-14, D-69120 Heidelberg (Germany)

We present the discovery of a very faint stellar system, SMASH 1, that is potentially a satellite of the Large Magellanic Cloud. Found within the Survey of the Magellanic Stellar History (SMASH), SMASH 1 is a compact (r{sub h}=9.1{sub −3.4}{sup +5.9} pc) and very low luminosity (M{sub V}=−1.0±0.9, L{sub V}=10{sup 2.3±0.4} L{sub ⊙}) stellar system that is revealed by its sparsely populated main sequence and a handful of red giant branch candidate member stars. The photometric properties of these stars are compatible with a metal-poor ([Fe/H]=−2.2) and old (13 Gyr) isochrone located at a distance modulus of ∼18.8, i.e., a distance of ∼57 kpc. Situated at 11.°3 from the LMC in projection, its three-dimensional distance from the Cloud is ∼13 kpc, consistent with a connection to the LMC, whose tidal radius is at least 16 kpc. Although the nature of SMASH 1 remains uncertain, its compactness favors it being a stellar cluster and hence dark-matter free. If this is the case, its dynamical tidal radius is only ≲19 pc at this distance from the LMC, and smaller than the system’s extent on the sky. Its low luminosity and apparent high ellipticity (ϵ=0.62{sub −0.21}{sup +0.17}) with its major axis pointing toward the LMC may well be the tell-tale sign of its imminent tidal demise.

• OSTI ID: 22868615
• Journal Information: Astrophysical Journal Letters, Vol. 830, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
DISTANCE
LUMINOSITY
MAGELLANIC CLOUDS
METALS
NONLUMINOUS MATTER
SATELLITES
SKY
STARS
THREE-DIMENSIONAL CALCULATIONS