Related papers: Precision Timing of Two Anomalous X-Ray Pulsars

We examine the timing history of several anomalous X-ray pulsars (AXPs), and find that they exhibit spin down irregularities statistically similar to those of radio pulsars. We propose that these irregularities are simply glitches like…

The Anomalous X-ray Pulsar (AXP) 1E 1547.0-5408 reactivated in 2009 January with the emission of dozens of short bursts. Follow-up observations with Swift/XRT and XMM-Newton showed the presence of multiple expanding rings around the…

We report on a multi-band high-energy observing campaign aimed at studying the long term spectral variability of the Anomalous X-ray Pulsar (AXP) 1RXS J170849.0-400910, one of the magnetar candidates. We observed 1RXS J170849.0-400910 in…

We have identified the third known accretion-powered millisecond pulsar, XTE J0929-314, with the Rossi X-Ray Timing Explorer. The source is a faint, high-Galactic-latitude X-ray transient (d >~ 5 kpc) that was in outburst during 2002…

It has long been thought that the pulsed X-ray properties of rotation-powered pulsars are stable on long time scales. However, long-term, systematic studies of individual sources have been lacking. Furthermore, dramatic X-ray variability…

PSR J1744-3922 is a binary pulsar exhibiting highly variable pulsed radio emission. We report on a statistical multi-frequency study of the pulsed radio flux variability which suggests that this phenomenon is extrinsic to the pulsar and…

Rossi X-ray Timing Explorer (RXTE) All-Sky Monitor (ASM) observations of the X-ray binary 2S0114+650 show modulations at periods close to both the optically derived orbital period (11.591 days) and proposed pulse period (~ 2.7 hr). The…

1E2259+586 belongs to the group of anomalous X-ray pulsars (AXP) which are thought to be magnetars. Accurate measurements of the proper motion for these interesting objects have not been made. In this work we use the data obtained by…

We report on the aperiodic X-ray timing and color behavior of the accreting millisecond X-ray pulsar (AMXP) IGR J17511-3057, using all the pointed observations obtained with the Rossi X-ray Timing Explorer Proportional Counter Array since…

HETE J1900.1--2455 is a peculiar accreting millisecond X-ray pulsar (AMXP) because it has shown intermittent pulsations after 22 days from the beginning of its outburst. The origin of intermittent pulses in accreting systems remains to be…

It is commonly believed that millisecond radio pulsars have been spun up by transfer of matter and angular momentum from a low-mass companion during an X-ray active mass transfer phase. A subclass of low-mass X-ray binaries is that of the…

We have used the 76-m Lovell, 94-m equivalent WSRT and 100-m Effelsberg radio telescopes to investigate the simultaneous single-pulse properties of the radio emitting magnetar AXP XTE J1810-197 at frequencies of 1.4, 4.8 and 8.35 GHz during…

Unique among neutron stars, 1E 1207.4-5209 is an X-ray pulsar with a spin period of 424 ms that contains at least two strong absorption features in its energy spectrum. This neutron star has been identified as a member of the radio-quiet…

In January 2009, multiple short bursts of soft gamma-rays were detected from the direction of the anomalous X-ray pulsar 1E 1547.0-5408 by different satellites. Here we report on the observations obtained with the INTEGRAL SPI-ACS detector…

We report X-ray imaging, timing, and spectral studies of XTE J1810-197, a 5.54s pulsar discovered by Ibrahim et al. (2003) in recent RXTE observations. In a set of short exposures with the Chandra HRC camera we detect a strongly modulated…

We present temporal analysis of the three outbursts of the X-ray millisecond pulsar SAX J1808.4-3658 that occurred in 1998, 2000 and 2002. With a technique that uses the chi^2 obtained with an epoch folding search to discriminate between…

We report on mid-infrared imaging observations of the anomalous X-ray pulsars (AXPs) 1E 1048.1-5937, 1RXS J170849-400910, and XTE J1810-197. The observations were carried out at 4.5 and 8.0 microns with the Infrared Array Camera and at 24…

We introduce a new method for analysing the aperiodic variability of coherent pulsations in accreting millisecond X-ray pulsars. Our method involves applying a complex frequency correction to the time-domain light curve, allowing for the…

The anomalous X-ray pulsars (AXPs) represent a growing class of neutron stars discovered at X-ray energies. While the nature of their multi-wavelength emission mechanism is still under debate, evidence has been recently accumulating in…

After spending almost a decade in a radio-quiet state, the Anomalous X-ray Pulsar XTE J1810-197 turned back on in early December 2018. We have observed this radio magnetar at 1.5 GHz with ~daily cadence since the first detection of radio…