Related papers: Characterizing the Evolving X-Ray Spectral Feature…
Type-I X-ray bursts on the surface of a neutron star are a unique probe to the accretion in X-ray binary systems. However, we know little about the feedback of the burst emission upon accretion. Hard X-ray shortages and enhancements of the…
In accreting neutron star X-ray transients, the neutron star crust can be substantially heated out of thermal equilibrium with the core during an accretion outburst. The observed subsequent cooling in quiescence (when accretion has halted)…
We present a new method of matching observations of Type I (thermonuclear) X-ray bursts with models, comparing the predictions of a semi-analytic ignition model with X-ray observations of the accretion-powered millisecond pulsar SAX…
We analyze 24 type I X-ray bursts from GS 1826-24 observed by the Rossi X-ray Timing Explorer between 1997 November and 2002 July. The bursts observed between 1997-98 were consistent with a stable recurrence time of 5.74 +/- 0.13 hr. The…
We investigate the latitude at which type I X-ray bursts are ignited on rapidly rotating accreting neutron stars. We find that, for a wide range of accretion rates, ignition occurs preferentially at the equator, in accord with the work of…
Neutron stars accreting matter from low-mass binary companions are observed to undergo bursts of X-rays due to the thermonuclear explosion of material on the neutron star surface. We use recent results on superfluid and superconducting…
We present a broadband spectral analysis of the atoll source 4U~1636-536 observed for $\sim92$ ks with \nustar{}. The source was found to be in a low-luminosity state during this observation with $3-79 \kev{}$ X-ray luminosity of $L_{3-79…
We report the detection with the BeppoSAX Wide Field Cameras of a superburst from 4U 1254-690. The superburst is preceded by a normal type-I X-ray burst, has a decay time that is the longest of all eight superbursts detected so far and a…
We investigate the impacts of neutrino cooling mechanism inside the neutron star (NS) core on the light curves of type-I X-ray bursts and X-ray superbursts. From several observations of NS thermal evolution, physical processes of fast…
After 6 years of quiescence, Anomalous X-ray Pulsar (AXP) 4U 0142+61 entered an active phase in 2006 March that lasted several months. During the active phase, several bursts were detected, and many aspects of the X-ray emission changed. We…
Thermonuclear flashes of hydrogen and helium accreted onto neutron stars produce the frequently observed Type I X-ray bursts. It is the current paradigm that almost all material burns in a burst, after which it takes hours to accumulate…
Type I X-ray bursts in GS 1826-24, and in several other systems, may induce cooling of the hot inner accretion flow that surrounds the bursting neutron star. Given that GS 1826-24 remained persistently in the hard state over the period…
The Be/X-ray transients V0332+53 and 4U 0115+63 exhibited giant, type-II outbursts in 2015. Here we present Swift/XRT follow-up observations at the end of those outbursts. Surprisingly, the sources did not decay back to their known…
The neutron star (NS) low-mass X-ray binary (LMXB) the Rapid Burster (RB; MXB 1730-335) uniquely shows both Type-I and Type-II X-ray bursts. The origin of the latter is ill-understood but has been linked to magnetospheric gating of the…
The source 4U 1901+03 is a high-mass X-ray pulsar than went into outburst in 2003. Observation performed with the Rossi X-ray Timing Explorer showed spectral and timing variability, including the detection of flares, quasi-periodic…
Iron emission lines at 6.4-6.97 keV, identified with Kalpha radiative transitions, are among the strongest discrete features in the X-ray band. These are one of the most powerful probes to infer the properties of the plasma in the innermost…
In many X-ray point sources on the sky, the X-ray emission arises because hydrogen and/or helium is accreted onto a neutron star from a nearby donor star. When this matter settles on the neutron star surface, it will undergo nuclear fusion.…
We investigate the time dependence of the frequency of X-ray brightness oscillations during thermonuclear bursts from several neutron star low mass X-ray binaries. We find that the oscillation frequencies in the cooling tails of X-ray…
We report the onset of a large amplitude, statistically significant periodicity (~46 d) in the RXTE/ASM data of the prototype X-ray burster 4U 1636-53, the X-ray flux of which has been gradually declining over the last four years. This…
The Be/X-ray pulsar 4U 0115+63 underwent a type II outburst in 2023. After the outburst, similar to the outbursts in 2015 and 2017, the source decayed into a quiescent state. Two out of three XMM-Newton observations conducted after the 2023…