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

        The variability in the UV resonance lines of the cataclysmic variables MU Cen, AH Her and QU Car

        Author
        Knigge, C.
        Drew, J.E.
        Hoare, M.G.
        Ladous, C.
        Attention
        2299/4048
        Abstract
        We present a time-variability study of the uV resonance lines Nv 1240, Si iv 1397 and C iv 1549 in the dwarf novae AH Her and MU Cen and the nova-like variable QU Car. The main findings are as follows. (i)Virtually no variation can be seen in our data for MU Cen. (ii) AH Her shows velocity shifting of its resonance lines, with semi-amplitudes ranging from approximately 500 to 800 km s1. Since the shifts appear to be linked to binary phase, this has been checked using a quantitative period-search procedure. In this procedure, three different techniques were used: the Lomb-Scargle periodogram, phase-dispersion minimization, and 2 minimization. Based primarily on comparisons with simulated data and a periodogram statistic due to Fisher, we find that we can significantly detect the orbital period in the velocity shifts. (iii) QU Car exhibits short-time-scale variations with a possible orbital trend in its uV resonance lines and/or continuum, but our data are insufficient to confirm the orbital nature of the variations. It is argued, on general grounds, that orbital-phase-linked variability of the UV resonance lines is more easily accounted for if it is due to departures from axisymmetry of the UV line emission from the accretion disc. The amplitudes of the velocity shifts suggest an inner disc location for this asymmetry in AH Her. The possibility of a secondary (uV) hotspot due to the interaction of the mass-transfer stream with the inner disc is considered.
        Publication date
        1994
        Published in
        Monthly Notices of the Royal Astronomical Society
        Other links
        http://hdl.handle.net/2299/4048
        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