相关论文: Transient neutron star X-ray binaries with Simbol-…
I have carried out a project to study the eccentric neutron-star binary Circinus X-1 through an extensive series of observational studies with the Rossi X-ray Timing Explorer satellite and through theoretical computer models I developed to…
We study an influence of X-ray photo-ionization from an accreting neutron star in a high mass X-ray binary. Our aim is to unveil a new principle governing X-ray luminosities of X-ray binaries, with a simple analysis of fluid equations…
We have observed the soft X-ray transient XTE J0421+56 in quiescence with XMM-Newton. The observed spectrum is highly unusual being dominated by a broad feature at 6.5 keV and can be modeled by a strongly absorbed continuum. The spectra of…
It is thought that neutron stars in low-mass binary systems can accrete matter and angular momentum from the companion star and be spun-up to millisecond rotational periods. During the accretion stage, the system is called a low-mass X-ray…
Several binary systems have been detected at High Energy (HE, E > 100 MeV) and/or Very High Energy (VHE, E > 100 GeV) gamma rays. Some of them are X-ray binaries in which accretion feeds relativistic radio jets and powers the non-thermal…
The advent of moderately high-resolution X-ray spectroscopy with Chandra and XMM promised to usher in a new age in the study of neutron stars: we thought we would study neutron stars like stars, with resolved absorption spectra revealing…
The observation of thermal emission from isolated neutron stars and the modeling of the corresponding cooling curves has been very useful to get information on the properties of matter at very high densities. More recently, the detection of…
Vela X-1 is the archetype of high-mass X-ray binaries, composed of a neutron star and a massive B supergiant. The supergiant is a source of a strong radiatively-driven stellar wind. The neutron star sweeps up this wind, and creates a huge…
Accreting millisecond X-ray pulsars are an important subset of low-mass X-ray binaries in which coherent X-ray pulsations can be observed during occasional, bright outbursts (X-ray luminosity $L_X\sim 10^{36}$ erg s$^{-1}$). These…
We analyze the currently available observations of X-ray binaries in a consistent way, to re-determine the masses of the neutron stars in these systems. In particular, our attention is focussed on a realistic and consistent assessment of…
A paper by Qian & Wasserburg suggests the optical absorption lines of uranium observed in the spectra of ultra-metal-poor stars (defined as [Fe/H] $<$-3) arise from contamination from a supernova in a binary star system. Assuming the binary…
We have observed the radio-quiet X-ray pulsar 1E 1207.4-5209 with the high throughput EPIC cameras onboard XMM-Newton. The spectrum of this peculiar source is characterized by two broad absorption features which present significant…
In this proof-of-concept study we demonstrate that in a binary system mass can be transferred toward an accreting compact object at extremely high rate. If the transferred mass is efficiently converted to X-ray luminosity (with disregard of…
Observations of soft X-ray transients (SXTs) in quiescence have found that the binaries harboring black holes are fainter than those that contain a neutron star. Narayan and collaborators postulated that the faint X-ray emission from black…
By definition transients are sudden events, some, like supernovae, are catastrophic, while others might be due to recurrent phenomena. The aim of studying transients is to reveal the physical conditions causing them, in this sense ideal…
Accreting neutron stars (NSs) represent a unique laboratory for probing the physics of accretion in the presence of strong magnetic fields ($B\gtrsim 10^8$ G). Additionally, the matter inside the NS itself exists in an ultra-dense, cold…
Recently the first finding of a spin period of an accreting neutron star in M31 is reported. The observed spin period is 1.2 s and it shows 1.27 d modulations due to orbital motion. From the orbital information, the mass donor could not be…
In this study, we examine the properties of donor stars of the three recently discovered ultraluminous X-ray sources (ULXs) powered by rotating neutron stars. For this purpose, we constructed a theoretical relation between the X-ray…
We review the polarization properties of X-ray emission from highly magnetized neutron stars, focusing on emission from the stellar surfaces. We discuss how x-ray polarization can be used to constrain neutron star magnetic field and…
Optical/near-infrared (optical/NIR; OIR) light from low-mass neutron star X-ray binaries (NSXBs) in outburst is traditionally thought to be thermal emission from the accretion disc. Here we present a comprehensive collection of…