SMASH 1: a very faint globular cluster disrupting in the outer reaches of the LMC?

• Published in: arXiv.org 2017-10
• Main Authors: Martin, Nicolas F, Jungbluth, Valentin, Nidever, David L, Bell, Eric F, Besla, Gurtina, Blum, Robert D, Cioni, Maria-Rosa L, Conn, Blair C, Kaleida, Catherine C, Gallart, Carme, Jin, Shoko, Majewski, Steven R, Martinez-Delgado, David, Monachesi, Antonela, Mñoz, Ricardo R, Noël, Noelia E D, Olsen, Knut, Olszewski, Edward W, Stringfellow, Guy S, Roeland P van der Marel, Vivas, A Katherina, Walker, Alistair R, Zaritsky, Dennis
• Format: Article
• Language: English
• Subjects: Disruption; Ellipticity; Iron; Luminosity; Magellanic clouds; Metallicity; Photometry; Star clusters
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1609.05918

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 (\(r_h = 9.1^{+5.9}_{-3.4}\) pc) and very low luminosity (M_V = -1.0 +/- 0.9, \(L_V=10^{2.3 +/- 0.4}\) Lsun) 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\(^\circ\) from the LMC in projection, its 3-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