6 papers
The X-ray source population of the globular cluster M15: Chandra high resolution imaging
D. C. Hannikainen, P. A. Charles, L. van Zyl +5
The globular cluster M15 was observed on three occasions with the High Resolution Camera on board Chandra in 2001 in order to investigate the X-ray source population in the cluster…
A new mass-ratio for the X-ray Binary X2127+119 in M15?
L. van Zyl, Z. Ioannou, P. A. Charles +1
The luminous low-mass X-ray binary X2127+119 in the core of the globular cluster M15 (NGC 7078), which has an orbital period of 17 hours, has long been assumed to contain a donor s…
The X-Ray Binary X2127+119 in M15: Evidence for a Very-Low-Mass, Stripped-Giant Companion
L. van Zyl, P. A. Charles, S. Arribas +3
We present integral field spectroscopy of X2127+119, the luminous X-ray binary in the globular cluster M15, obtained with INTEGRAL/WYFFOS on the William Herschel Telescope. We find…
The Nonradially-Pulsating Primary of the Cataclysmic Variable GW Librae
L. van Zyl, B. Warner, D. O'Donoghue +11
The dwarf nova GW Librae is the first cataclysmic variable discovered to have a primary in a white dwarf instability strip, making it the first multi-mode, nonradially-pulsating st…
Spectroscopy of the Optical Counterpart to Ser X-1
R. I. Hynes, P. A. Charles, L. van Zyl +4
We present WHT and VLT spectroscopy of MM Ser, the optical counterpart to Ser X-1. We deblend the red spectra of the two close stars identified by Wachter (1997) and show that the…
Understanding the LMXB X2127+119 in M15
Zach Ioannou, L. van Zyl, T. Naylor +4
We present HST UV observations of the high-inclination low mass X-ray binary AC211 (X2127+119), which is located in the globular cluster M15 (NGC 7078). We have discovered a CIV P…