Related papers: A Double Outburst from IGR J00291+5934: Implicatio…
The accreting millisecond X-ray pulsar Swift J1756.9$-$2508 went into outburst in April 2018 and June 2019, 8.7 yr after the previous activity period. We investigated the temporal, timing and spectral properties of these two outbursts using…
IGR J17591$-$2342 is a 527-Hz accreting millisecond X-ray pulsar that was discovered in outburst in 2018 August. In this paper, we present quasi-simultaneous radio and X-ray monitoring of this source during the early part of the outburst.…
The accreting millisecond X-ray pulsar SAX J1808.4--3658 shows peculiar low luminosity states known as "reflares" after the end of the main outburst. During this phase the X-ray luminosity of the source varies by up to three orders of…
We present the results obtained from detailed X-ray timing and spectral studies of X-ray pulsar Swift J0243.6+6124 during its giant and normal X-ray outbursts between 2017 and 2023 observed by the Neutron star Interior Composition Explorer…
During the observation of the Galactic-center field by the INTEGRAL observatory on September 9, 2003, the IBIS/ISGRI gamma-ray telescope detected a short (several-hours-long) intense (~380 mCrab at the peak) outburst of hard radiation from…
In this Paper we report on our analysis of three Chandra observations of the accretion-powered millisecond X-ray pulsar IGR J00291+5934 obtained during the late stages of the 2004 outburst. We also report the serendipitous detection of the…
The spin frequency distribution of accreting millisecond X-ray pulsars cuts off sharply above 730 Hz, well below the breakup spin rate for most neutron star equations of state. I review several different ideas for explaining this cutoff.…
Thermonuclear (type-I) bursts exhibit properties that depend both on the local surface conditions of the neutron stars on which they ignite, as well as the physical parameters of the host binary system. However, constraining the system…
The transient accreting millisecond pulsar SAX J1808.4-3658 has shown several outbursts to date but the transition from outburst to quiescence has never been investigated in detail. Thanks to the Swift observing flexibility, we monitored…
In this paper we present a coherent timing analysis of the 401 Hz pulsations of the accreting millisecond X-ray pulsar SAX J1808.4-3658 during its 2019 outburst. Using observations collected with the Neutron Star Interior Composition…
The supergiant fast X-ray transient source IGR J16479-4514 was observed in outburst two times with Swift. Its quiescent state was investigated in-depth only once in 2008 through a relatively long pointed observation with XMM-Newton. The…
We present MAXI and NuSTAR observations of the Be X-ray binary, MAXI J0655-013, in outburst. NuSTAR observed the source once early in the outburst, when spectral analysis yields a bolometric (0.1--100 keV), unabsorbed source luminosity of…
We present results from timing and spectral analysis of the HMXB X-ray pulsar IGR J19294+1816 observed using \asr during its recent Type-I outburst in October, 2019. AstroSat observations sampled the outburst at the decline phase right…
We report on the X-ray aperiodic timing analysis of two accreting millisecond pulsars: XTE J1807-294 and IGR J00291+5934. On the one hand, we discovered in XTE J1807-294 seven pairs of simultaneous kilohertz quasi-periodic oscillations (kHz…
SDSS J080434.20+510349.2 is the 13th dwarf nova containing a pulsating white dwarf. Among the accreting pulsators that have experienced a dwarf novae outburst, SDSS J0804 has the most dramatic history of events within a short time scale:…
Millisecond X-ray pulsars consist of a rapidly-spinning neutron star accreting from a low-mass stellar companion, and are the long-sought evolutionary progenitors of millisecond radio pulsars, as well as promising candidate sources for…
The X-ray pulsar RX J0440.9+4431 went through a giant outburst in 2022 and reached a record-high flux of 2.3 Crab, as observed by Swift/BAT. We study the evolution of different spectral and timing properties of the source using NICER…
IGR J17591--2342, a transient accretion-powered millisecond X-ray pulsar, was discovered during its 2018 outburst. Here, we present a timing and spectral analysis of the source using {\it AstroSat} data of the same outburst. From the timing…
We report a major outburst from the Anomalous X-ray Pulsar 1E 2259+586, in which over 80 X-ray bursts were detected in four hours using the Rossi X-ray Timing Explorer. The bursts range in duration from 2 ms to 3 s and have fluences in the…
SDSS J080434.20+510349.2 is the WZ type binary that displayed rare outburst in 2006 (Pavlenko et al., 2007). During the long-lasting tail of the late stage of the outburst binary shown the two-humped or four-humped profile of the orbital…