University of Hertfordshire Research Archive

        JavaScript is disabled for your browser. Some features of this site may not work without it.

        Browse

        All of UHRABy Issue DateAuthorsTitlesThis CollectionBy Issue DateAuthorsTitles

        Arkivum Files

        My Downloads
        View Item 
        • UHRA Home
        • University of Hertfordshire
        • Research publications
        • View Item
        • UHRA Home
        • University of Hertfordshire
        • Research publications
        • View Item

        Globular clusters as probes of galaxy evolution : NGC 5128

        View/Open
        906502.pdf (PDF, 466Kb)
        Author
        Yi, S.K.
        Kaviraj, S.
        Yoon, S.-J.
        Peng, E.
        Ford, H.
        Attention
        2299/11440
        Abstract
        We present the results of our analysis of the photometric data of globular clusters in the elliptical galaxy NGC 5128 (Cen A). We show that the integrated colour U - B can be an effective metallicity indicator for simple stellar populations. This is because it is sensitive to metallicity via the opacity effect but relatively insensitive to the effective main-sequence turn-off temperature of the population (and thus to age) when T ≈ 7000-12 000 K, that is, when the Balmer Jump is strong. This flat U - B versus T relation is a result of the fact that the blueing effect of the optical continuum with increasing temperature is temporarily stopped by the Balmer Jump, which becomes greater with temperature in this range. In this study we use U - B and B - V as metallicity and age indicators, respectively. We first show that the use of the U - B versus B - V two-colour diagram roughly yields the metallicities and ages of the Milky Way globular clusters independently determined, and then apply the technique to the clusters in NGC 5128. There is a large range in U - B, which corresponds to [Fe/H] of from -2.0 to over +0.3. The large uncertainties from the data and the models currently prevent us from pinning down their ages and metallicities. Although a constant age for all these clusters cannot be ruled out, there is a hint of the metal-rich clusters being younger. Significance of these results and caveats of the analysis are discussed.
        Publication date
        2004-04-21
        Published in
        Monthly Notices of the Royal Astronomical Society
        Published version
        https://doi.org/10.1111/j.1365-2966.2004.07614.x
        Other links
        http://hdl.handle.net/2299/11440
        Metadata
        Show full item record
        Keep in touch

        © 2019 University of Hertfordshire

        I want to...

        • Apply for a course
        • Download a Prospectus
        • Find a job at the University
        • Make a complaint
        • Contact the Press Office

        Go to...

        • Accommodation booking
        • Your student record
        • Bayfordbury
        • KASPAR
        • UH Arts

        The small print

        • Terms of use
        • Privacy and cookies
        • Criminal Finances Act 2017
        • Modern Slavery Act 2015
        • Sitemap

        Find/Contact us

        • T: +44 (0)1707 284000
        • E: ask@herts.ac.uk
        • Where to find us
        • Parking
        • hr
        • qaa
        • stonewall
        • AMBA
        • ECU Race Charter
        • disability confident
        • AthenaSwan