158 citations · 1.1k across the 34 of their papers we have counts for
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Periodicities in the high-mass X-ray binary system RX J0146.9+6121/LS I+61 235
Gordon E. Sarty, Laszlo L. Kiss, Richard Huziak +10
The high-mass X-ray binary RX J0146.9+6121, with optical counterpart LS I+61 235 (V831 Cas), is an intriguing system on the outskirts of the open cluster NGC 663. It contains the s…
The clustering of radio galaxies at z~0.55 from the 2SLAQ LRG survey
David A. Wake, Scott M. Croom, Elaine M. Sadler +1
We examine the clustering properties of low-power radio galaxies at redshift 0.4<z<0.8, using data from the 2SLAQ Luminous Red Galaxy (LRG) survey. We find that radio-detected LRGs…
Radio galaxies in the 2SLAQ Luminous Red Galaxy survey: II. The stellar populations of radio-loud and radio-quiet LRGs
Helen M. Johnston, Elaine M. Sadler, Russell Cannon +3
We present an analysis of the optical spectra of a volume-limited sample of 375 radio galaxies at redshift 0.4<z<0.7 from the 2dF-SDSS Luminous Red Galaxy and QSO (2SLAQ) redshift…
Finding Periods in High Mass X-Ray Binaries
Gordon E. Sarty, Laszlo L. Kiss, Helen M. Johnston +2
This is a call for amateur astronomers who have the equipment and experience for producing high quality photometry to contribute to a program of finding periods in the optical ligh…
Radio galaxies in the 2SLAQ Luminous Red Galaxy Survey: I. The evolution of low-power radio galaxies to z~0.7
Elaine M. Sadler, Russell D. Cannon, Tom Mauch +15
We have combined optical data from the 2dF-SDSS Luminous Red Galaxy and QSO (2SLAQ) redshift survey with radio measurements from the 1.4 GHz VLA FIRST and NVSS surveys to identify…
A search for distant radio galaxies from SUMSS and NVSS: II. Optical Spectroscopy
Carlos De Breuck, Ilana Klamer, Helen Johnston +4
This is the second in a series of papers presenting observations and results for a sample of 76 ultra-steep-spectrum (USS) radio sources in the southern hemisphere designed to find…
MRC B1221-423: a compact steep-spectrum radio source in a merging galaxy
Helen M. Johnston, Richard W. Hunstead, Garret Cotter +1
We present BVRIK images and spectroscopic observations of the z=0.17 host galaxy of the compact steep-spectrum radio source MRC B1221-423. This is a young (~1e5 yr) radio source wi…
An ultra-relativistic outflow from a neutron star accreting gas from a companion
Rob Fender, Kinwah Wu, Helen Johnston +4
Collimated relativistic outflows, or jets, are amongst the most energetic and relativistic phenomena in the Universe. They are associated with supermassive black holes in distant a…
Secular and orbital variability of Cir X-1 observed in optical spectra
Helen M. Johnston, Kinwah Wu, Rob Fender +1
We have observed variations in the optical emission lines from the X-ray binary Circinus X-1. These variations may be attributed both to orbital variations and to long term secular…
Formation of optical lines in black-hole binaries
Kinwah Wu, Roberto Soria, Helen Johnston +1
The HI Balmer emission lines of black-hole binaries show double-peaked profiles during the high-soft state and the quiescent state. In the high-soft state the profiles are asymmetr…
Optical Spectroscopy of GX339-4 during the High-Soft and Low-Hard States II: Line Ionisation and Emission Region
Kinwah Wu, Roberto Soria, Richard W. Hunstead +1
We have carried out observations of the X-ray transient GX339-4 during its high-soft and low-hard X-ray spectral states. Our high-resolution spectroscopic observation in 1999 April…
Multiple and variable X-ray sources in the globular clusters omega Cen, NGC6397, NGC6752, and Liller 1
Frank Verbunt, Helen M. Johnston
We detect stars from the Hipparcos and Tycho Catalogues in the field of view of observations with the ROSAT HRI of three globular clusters. We use the positions of these stars to r…
Circinus X-1: survivor of a highly asymmetric supernova
T. M. Tauris, R. P. Fender, E. P. J. van den Heuvel +2
We have analyzed the kinematical parameters of Cir X-1 to constrain the nature of its companion star, the eccentricity of the binary and the pre-supernova parameter space. We argue…
Optical Spectroscopy of GX339-4 During the High-Soft and Low-Hard States (Paper I)
Roberto Soria, Kinwah Wu, Helen Johnston
We carried out spectroscopic observations of the candidate black-hole binary GX339-4 during its low-hard and high-soft X-ray states, in 1997 and 1998 respectively. We have found th…
High resolution optical and infrared spectroscopic observations of Cir X-1
Helen Johnston, Rob Fender, Kinwah Wu
We present new optical and infrared (IR) observations of Cir X-1 taken near apastron. Both sets of spectra show asymmetric emission lines. Archival optical observations show that a…