Related papers: Circinus X-1: survivor of a highly asymmetric supe…
We present optical spectra and images of the X-ray binary Circinus X-1. The optical light curve of Cir X-1 is strongly variable, changing in brightness by 1.2 magnitudes in the space of four days. The shape of the light curve is consistent…
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 an asymmetric H-alpha emission line has been in evidence for…
Cir X-1 is one of the most intriguing galactic X-ray sources. It is a ~16.6 days variable X/radio source, a type-I X-ray burster and a QPO emitter. In spite of an uncertain optical counterpart classification, all these properties identify…
Because supernova remnants are short lived, studies of neutron star X-ray binaries within supernova remnants probe the earliest stages in the life of accreting neutron stars. However, such objects are exceedingly rare: none were known to…
In recent years, accurate observational constraints become available for an increasing number of Galactic X-ray binaries. Together with proper motion measurements, we could reconstruct the full evolutionary history of X-ray binaries back to…
Cygnus X-2 appears to be the descendant of an intermediate-mass X-ray binary (IMXB). Using Mazzitelli's (1989) stellar code we compute detailed evolutionary sequences for the system and find that its prehistory is sensitive to stellar input…
We present the results of millimetre (33 and 35 GHz) and centimetre (2.1, 5.5 and 9.0 GHz) wavelength observations of the neutron star X-ray binary Circinus X-1, using the Australia Telescope Compact Array. We have used advanced calibration…
Cygnus X-1 is a binary star system that is comprised of a black hole and a massive giant companion star in a tight orbit. Building on our accurate distance measurement reported in the preceding paper, we first determine the radius of the…
Circinus X-1 (Cir X-1) is a neutron star binary with an elliptical orbit of 16.6~days. The source is unique for its extreme youth, providing a key to understanding early binary evolution. However, its X-ray variability is too complex to…
We report on the spectral analysis of Circinus X-1 observed by the ASCA satellite in March 1998 along one orbital period. The luminosity of the source (in the 0.1-100 keV band) ranges from $2.5 \times 10^{38}$ erg s$^{-1}$ at the periastron…
A strongly relativistic binary pulsar has been recently discovered with the 64m Parkes telescope (Burgay et al. 2003). Here we use the measured properties of this binary (masses and orbital characteristics as well as age estimates), and we…
We have recently measured the angle between the spin and orbital angular momenta of PSR B1534+12 to be either 25+/-4 deg or 155+/-4 deg. This misalignment was almost certainly caused by an asymmetry in the supernova explosion that formed…
Using phase resolved spectroscopic observations obtained with the Ultraviolet and Visual Echelle Spectrograph on ESO's Kueyen Very Large Telescope supplemented by spectroscopic observations obtained with the Boller and Chivens Spectrograph…
We propose that a non-thermal X-ray arc inside the remnant of Tycho's supernova (SN) represents the interaction between the SN ejecta and the companion star's envelope lost in the impact of the explosion. The X-ray emission of the remnant…
We present results from the first radio observations of a complete orbit (~ 17 days) of the neutron star X-ray binary Circinus X-1 using the Australia Telescope Compact Array Broadband Backend, taken while the system was in an historically…
Cir X-1 is a neutron star X-ray binary characterized by strong variations in flux during its eccentric $\sim$16.6 days orbit. There are also strong variations in the spectral state, and historically it has shown both atoll and Z state…
Be stars are rapidly spinning B stars surrounded by an outflowing disc of gas in Keplerian rotation. Be star/X-ray binary systems contain a Be star and a neutron star. They are found to have non-zero eccentricities and there is evidence…
In this Paper we report on optical spectroscopic observations of the low-mass X-ray binary 2S 0921-630 obtained with the Very Large Telescope. We found sinusoidal radial velocity variations of the companion star with a semi-amplitude of…
Recent observations of the high-mass X-ray binary Cygnus X-1 have shown that both the companion star (41 solar masses) and the black hole (21 solar masses) are more massive than previously estimated. Furthermore, the black hole appears to…
The absence or presence of extremely wide binaries with a radio pulsar and an optical counterpart imposes a strong constraint on the existence and magnitude of kicks in supernova explosions. We search for such systems by comparing the…