Related papers: Accretion column disruption in GX 1+4
We report the detection of pulsations with $\sim 124$ s period in V2116 Oph, the optical counterpart of the low-mass X-ray binary GX 1+4. The pulsations are sinusoidal with modulation amplitude of up to 4% in blue light and were observed in…
We present detailed spectral and timing studies using a NuSTAR observation of GX 1+4 in October 2015 during an intermediate intensity state. The measured spin period of 176.778 s is found to be one of the highest values since its discovery.…
The November 1999 outburst of the transient pulsar SAX J2103.5+4545 was monitored with the large area detectors of the Rossi X-Ray Timing Explorer until the pulsar faded after a year. The 358 s pulsar was spun up for 150 days, at which…
Using RXTE/ASM archival data, we investigate the behaviour of the spectral hardness ratio as a function of X-ray luminosity in a sample of six transient X-ray pulsars (EXO 2030+375, GX 304-1, 4U 0115+63, V 0332+63, A 0535+26 and MXB…
We present the detection of a positive correlation between spin-down rate $\dot{P}$ and pulsed X-ray luminosity in the BATSE archival data of the bright hard X-ray pulsar GX 1+4. We have also seen a delay of 5.6 $\pm$ 1.2 days between the…
We aim both to complement the existing data on the spin history of the peculiar accreting X-ray pulsar GX 1+4 with more past and current data from BeppoSAX, INTEGRAL, and Fermi and to interpret the evolution in the framework of accretion…
We report on the long-term monitoring of three anomalous X-ray pulsars using the Rossi X-ray Timing Explorer (RXTE). We present a phase-coherent timing ephemeris for 4U 0142+61, and show that it has rotated with high stability over 4.4 yr,…
The X-ray binary pulsar GX 1+4 was observed with Ginga every year from 1987 to 1991, and with ASCA in 1994. During the Ginga observations, GX 1+4 was in the steady spindown phase, while the X-ray flux was not steady. The X-ray luminosity…
We report on 10 years of monitoring of the 8.7-s Anomalous X-ray Pulsar 4U 0142+61 using the Rossi X-Ray Timing Explorer (RXTE). This pulsar exhibited stable rotation from 2000 March until 2006 February: the RMS phase residual for a…
We report the detection of an anomalous accretion flare in the tight eccentric pre-main-sequence binary system DQ Tau. In a multi-epoch survey consisting of randomly acquired low to moderate resolution near-infrared spectra obtained over a…
The accretion-powered, X-ray pulsar 4U 1626-67 has recently shown an abrupt torque reversal accompanied by a dramatic spectral transition and a relatively small luminosity change. The time-averaged X-ray spectrum during spin-down is…
In order to probe the activity of the inner disk flow and its effect on the neutron star surface emissions, we carried out the timing analysis of the Rossi X-Ray Timing Explorer (RXTE) observations of the millisecond X-ray pulsar XTE…
We have analyzed 3 observations of the High Mass X-ray Binary A0535+26 performed by the Rossi X-ray Timing Explorer (RXTE) 3, 5, and 6 months after the last outburst in 2011 February. We detect pulsations only in the second observation. The…
We present X-ray light curves and energy spectra for the persistent accreting pulsars 4U 1626-67 and GX 301-2 measured by the All-Sky Monitor (ASM) on Ginga from 1987 March - 1991 October. We compare these with simultaneous and near…
We analyze the observations of the X-ray pulsar LMC X-4 performed by the INTEGRAL observatory and the All-Sky Monitor (ASM) of the RXTE observatory over a wide energy range. The observed hard X-ray flux from the source is shown to change by…
RXTE observations of the X-ray transient pulsar 2S 1417-62 between 1999 November and 2000 August with a total exposure of $\sim 394$ ksec were analyzed. Observations include a main outburst followed by a series of mini outbursts. Changes in…
We present analysis of RXTE--PCA observations of GX 1+4 between March 3, 2001 and January 31, 2003 together with the CGRO--BATSE X-ray flux and frequency derivative time series between 1991 and 1999. From the timing analysis of RXTE-PCA…
We report the discovery of a new, bright (V = 17 mag) AM Her system as the optical counterpart of the soft ROSAT All-Sky-Survey source RX J1846.9+5538 (= 1RXS J184659.4+553834). Optical photometric and spectroscopic follow-up observations…
We present the results of a detailed study of the high mass X-ray binary 2S 0114+650 made with the pointed instruments onboard the Rossi X-ray Timing Explorer. The spectral and temporal behaviour of this source was examined over the pulse,…
We present the results from the analysis of the broad-band X-ray spectra of 5 Anomalous X-ray Pulsars (AXPs) and Soft $\gamma$-ray Repeaters (SGRs). We fit their Suzaku and INTEGRAL spectra with models appropriate for the X-ray emission…