Cataclysmic Variables in Globular Clusters and Low Mass X-Ray Binaries.
Abstract
Available from UMI in association with The British Library. Requires signed TDF. An introduction is given to cataclysmic variables (CVs), low mass X-ray binaries (LMXBs) and globular clusters. The radio properties of LMXBs are reviewed. I present optical spectroscopy and photometry of the globular cluster CV candidates, V4 in M30, V101 in M5, the CV candidates in M71 and of the LMXB 4U0614 + 09. VLA observations of the globular cluster X-ray sources in NGC7078, NGC6712, NGC6624 and NGC1851 and a "snapshot" of the galactic LMXB 4U2129 + 47 are presented. The quiescent colours of V4 indicate that its orbital period is <5 hours. Its radial velocity, quiescent and outburst magnitudes show that it is probably not a cluster member. A hump in the light curve of V101, its quiescent colours, outburst magnitude and the results of quiescent state time resolved spectroscopy are all consistent with an orbital period of ~ 5-8 hours. V101 is the only CV whose photometric properties are compatible with cluster membership. Spectroscopy of the two brightest CV candidates in M71 shows that they are subdwarf B stars. The nature of the remaining candidates is discussed. Radio counterparts to the X-ray sources in NGC7078 and NGC6712 are discovered. The observed emission is interpreted in terms of the synchrotron emission mechanism. Upper limits are placed on radio emission from the X-ray sources in NGC6624 and NGC1851 and from the galactic LMXB 4U2129 + 47. 4U0614 + 09 displays photometric variability on two timescales; 10 days and 1 hour. The former is interpreted as a precessing accretion disc whilst the latter could be either long timescale QPO or the orbital period. The optical spectrum is unusual because it only displays the Bowen blend (lambda4640-4660) emission feature not He II lambda4686. Possible explanations for this behaviour are discussed. Simultaneous optical and X-ray photometry shows that the optical flux was anticorrelated with the X-ray emission.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- 1990
- Bibcode:
- 1990PhDT........17M
- Keywords:
-
- Physics: Astronomy and Astrophysics;
- Astronomical Photometry;
- Astronomical Spectroscopy;
- Cataclysmic Variables;
- Globular Clusters;
- X Ray Binaries;
- Light Curve;
- Radio Emission;
- Stellar Color;
- Synchrotron Radiation;
- Variability;
- Very Large Array (Vla);
- X Ray Sources;
- Astrophysics