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Mercer 5: A probable new globular cluster in the Galactic bulge

Longmore, A.J., Kurtev, R., Lucas, P.W., Froebrich, D., de Grijs, R., Ivanov, V.D., Maccarone, T.J., Borissova, J., Ker, L.M. (2011) Mercer 5: A probable new globular cluster in the Galactic bulge. Monthly Notices of the Royal Astronomical Society, 416 (1). pp. 465-478. ISSN 0035-8711. (doi:10.1111/j.1365-2966.2011.19056.x)

Abstract

We present a detailed study of a dust-obscured Galactic star cluster Mercer 5 ([MCM2005b] 5) in an extremely crowded field in the Milky Way. Near-infrared (near-IR) photometry from United Kingdom Infrared Digital Sky Surveys (UKIDSS) and the Son of ISAAC on the New Technology Telescope (SofI/NTT), combined with near-IR spectroscopy also from SofI, indicates that it is almost certainly a Galactic globular cluster, located at the edge of the Galactic bulge. The cluster suffers ~9 mag of visual extinction, with strong evidence for an extinction gradient across the cluster. A simulation of the differential reddening in the cluster using empirical data from NGC 6539 (chosen because it had high signal-to-noise ratio data and low field star contamination) as a template mimics the observations extremely well. This simulation and other arguments are used to indicate that the most prominent clump of stars in the colour-magnitude diagrams is a horizontal branch clump. On this basis we conclude that the cluster is at a distance of ~5.5kpc and suffers from visual extinction ranging from ~8.5 to ~12.5 mag. Alternative explanations for its nature, such as a young cluster or an old open cluster, are much less likely, on the grounds of no visible main sequence or stars with IR excesses for the former and location versus lifetime arguments for the latter. © 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS.

Item Type: Article
DOI/Identification number: 10.1111/j.1365-2966.2011.19056.x
Additional information: Unmapped bibliographic data: LA - English [Field not mapped to EPrints] J2 - Mon. Not. R. Astron. Soc. [Field not mapped to EPrints] AD - UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, United Kingdom [Field not mapped to EPrints] AD - Departamento de Física y Astronomía, Facultad de Ciencias, Universidad de Valparaíso, Av. Gran Bretaña 1111, Playa Ancha, Casilla 5030, Valparaíso, Chile [Field not mapped to EPrints] AD - Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield AL10 9AB, United Kingdom [Field not mapped to EPrints] AD - Centre for Astrophysics and Planetary Science, University of Kent, Canterbury CT2 7NH, United Kingdom [Field not mapped to EPrints] AD - Kavli Institute for Astronomy and Astrophysics, Peking University, Yi He Yuan Lu 5, Hai Dian District, Beijing 100871, China [Field not mapped to EPrints] AD - European Southern Observatory, Ave. Alonso de Cordova 3107, Casilla 19, Santiago 19001, Chile [Field not mapped to EPrints] AD - School of Physics and Astronomy, University of Southampton, Hampshire SO17 1BJ, United Kingdom [Field not mapped to EPrints] AD - Institute for Astronomy, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, United Kingdom [Field not mapped to EPrints] DB - Scopus [Field not mapped to EPrints]
Uncontrolled keywords: Galaxy: abundances, Globular clusters: general, Globular clusters: individual: Mercer 5: [MCM2005b] 5, Stars: abundances, Stars: distances
Subjects: Q Science > QB Astronomy > QB460 Astrophysics
Divisions: Faculties > Sciences > School of Physical Sciences > Centre for Astrophysics and Planetary Sciences
Depositing User: Giles Tarver
Date Deposited: 21 Jul 2015 10:02 UTC
Last Modified: 29 May 2019 14:51 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/49562 (The current URI for this page, for reference purposes)
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