Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.682166
Title: Properties of star clusters
Author: Buckner, Anne
ISNI:       0000 0004 5923 1604
Awarding Body: University of Kent
Current Institution: University of Kent
Date of Award: 2016
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Abstract:
Star clusters are tracers of both stellar and Galactic evolution. As such it is essential to analyse their properties and distribution in the Galaxy. Ideally clusters’ fundamental properties (distance, reddening, age, metallicity) should be derived homogeneously, so that their uncertainties are systematic and any global trends identified can be trusted. With the increase of newly discovered, purely photometric, large cluster samples from infrared surveys such as 2MASS, WISE, UKIDSS-GPS and VISTA-VVV, new methods to reliably derive these properties are required. This Thesis presents novel methods to homogeneously derive the distances, extinctions, ages and scale height measurements of cluster samples. Distances and extinctions are derived from photometry alone, without the use of isochrone fitting, and cluster distances can be estimated with a better than 40% accuracy. Cluster ages are derived using a pipeline which is designed to consistently determine the values of clusters’ fundamental properties. Novel scale height measurements are established with a 25% uncertainty for a sample size of 38. Using these methods, the FSR List cluster catalogue is found to be biased towards a distance of 3 kpc and modal age of 400 Myr. A dependence between the interstellar absorption value and Galactic longitude is found, characterised by AH (l)[mag/kpc] = 0.10+0.001 × |l−180 ◦ |/ ◦ for regions more than 60 ◦ from the Galactic Centre. The temporal scale height evolution of clusters is accurately traced for the first time. A linear relationship between cluster scale height and log(age/yr) is found which is significantly different from the stellar component of the Galactic Disk. There is also a weak age-independent trend between cluster scale height and Galactocentric distance. No significant temporal or spatial variations of the cluster distribution vertical zero point are found. The Sun’s vertical displacement from the Galactic Plane is measured to be Z⊙ = 18.5 ± 1.2 pc.
Supervisor: Froebrich, Dirk ; Smith, Michael Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.682166  DOI: Not available
Keywords: Q Science
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