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Properties of star clusters - I. Automatic distance and extinction estimates

Buckner, A.S.M, Froebrich, Dirk (2013) Properties of star clusters - I. Automatic distance and extinction estimates. Monthly Notices of the Royal Astronomical Society, 436 (2). pp. 1465-1478. ISSN 0035-8711. (doi:10.1093/mnras/stt1665)

Abstract

Determining star cluster distances is essential to analyse their properties and distribution in the Galaxy. In particular, it is desirable to have a reliable, purely photometric distance estimation method for large samples of newly discovered cluster candidates e.g. from the Two Micron All Sky Survey, the UK Infrared Deep Sky Survey Galactic Plane Survey and VVV. Here, we establish an automatic method to estimate distances and reddening from nearinfrared photometry alone, without the use of isochrone fitting.We employ a decontamination procedure of JHK photometry to determine the density of stars foreground to clusters and a galactic model to estimate distances. We then calibrate the method using clusters with known properties. This allows us to establish distance estimates with better than 40 per cent accuracy. We apply our method to determine the extinction and distance values to 378 known open clusters and 397 cluster candidates from the list of Froebrich, Scholz & Raftery. We find that the sample is biased towards clusters of a distance of approximately 3 kpc, with typical distances between 2 and 6 kpc. Using the cluster distances and extinction values, we investigate how the average extinction per kiloparsec distance changes as a function of the Galactic longitude. We find a systematic dependence that can be approximated by AH(â??)[mag kpc-1] = 0.10 + 0.001 Ã? |â?? - 180°|/° for regions more than 60° from the Galactic Centre. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

Item Type: Article
DOI/Identification number: 10.1093/mnras/stt1665
Additional information: This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record "Properties of star clusters - I. automatic distance and extinction estimates", Anne S.M. Buckner and Dirk Froebrich, is available online at: http://www.dx.doi.org/10.1093/mnras/stt1665
Uncontrolled keywords: stars, distances, fundamental parameters, statistics, dust, extinction, open clusters and associations, galaxies, star cluster
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: 20 Jul 2015 13:05 UTC
Last Modified: 29 May 2019 14:51 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/49553 (The current URI for this page, for reference purposes)
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