Related papers: Simultaneous multi-frequency single-pulse properti…
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…
Millisecond pulsars (MSPs) are known as highly stable celestial clocks. Nevertheless, recent studies have revealed the unstable nature of their integrated pulse profiles, which may limit the achievable pulsar timing precision. In this…
Swift J1818.0-1607 is a radio-loud magnetar with a spin period of 1.36 s and a dipolar magnetic field strength of B~3E14 G, which is very young compared to the Galactic pulsar population. We report here on the long-term X-ray monitoring…
The phenomenon of sub-pulse drifting is an important single-pulse phenomenon that can potentially provide important insights into the elusive radio emission mechanism in pulsars. We analyze the frequency behaviour of the single pulses of…
The accreting millisecond pulsar XTE J1814-338 exhibits oscillations at the known spin frequency during Type I X-ray bursts. The properties of the burst oscillations reflect the nature of the thermal asymmetry on the stellar surface. We…
Magnetars are slowly rotating, highly magnetized young neutron stars that can show transient radio phenomena for radio pulses and fast radio bursts. We conducted radio observations of from two magnetars SGR$~$J1935+2154 and…
Recent studies have shown possible connections between highly magnetized neutron stars ("magnetars"), whose X-ray emission is too bright to be powered by rotational energy, and ordinary radio pulsars. In addition to the magnetar SGR…
SAX J1748.9-2021 is a transient accretion powered millisecond X-ray pulsar located in the Globular cluster NGC 6440. We report on the spectral and timing analysis of SAX J1748.9-2021 performed on AstroSat data taken during its faint and…
We report the detection of strong, highly circularly polarised, and rotationally modulated radio pulses from the early-mid M dwarf ASKAP J181335-604720, based on strictly simultaneous radio and optical observations with the Australian…
We revisit the phenomenon of pulse nulling using high-quality single-pulse data of PSR B1133+16 from simultaneous multifrequency observations. Observations were made at 325, 610, 1400 and 4850 MHz as part of a joint program between the…
We report on the hard X-ray burst and the first ~100 days NICER monitoring of the soft X-ray temporal and spectral evolution of the newly-discovered magnetar Swift J1818.0-1607. The burst properties are typical of magnetars with a duration…
Aims. We aim to elucidate the pulsar radio emission by studying several single-pulse phenomena, how they relate, and how they evolve with observing frequency. We intend to inspire models for the pulsar radio emission and fast radio bursts.…
We have analyzed XMM-Newton and Chandra observations of the transient magnetar XTE J1810-197, spanning more than 11 years, from the initial phases of the 2003 outburst to the current quiescent level. We investigated the evolution of the…
We present radio coverage of the 2019 outburst of the accreting millisecond X-ray pulsar SAX J1808.4-3658, obtained with MeerKAT. We compare these data to contemporaneous X-ray and optical measurements in order to investigate the coupling…
The 2011 outburst of Swift J1822.3--1606 was extraordinary; periodic modulations at the spin period of the underlying neutron star were clearly visible, remarkably similar to what is observed during the decaying tail of magnetar giant…
The comparative analysis of parameters is carried out for two samples of radio pulsars. Objects of the first sample have periods P > 2 sec, the second is characterized by magnetic fields at the neutron star surface $Bs > 4.4\times10^{13}$…
We observed the anomalous X-ray pulsar 4U 0142+61 using the Proportional Counter Array (PCA) aboard the Rossi X-ray Timing Explorer (RXTE) in March 1996. The pulse frequency was measured as f = 0.11510039(3) Hz with an upper limit of df/dt…
At present, ten years after they were first discovered, ten accreting millisecond pulsars are known. I present a study of the aperiodic X-ray variability in three of these systems, which led to the discovery of simultaneous kHz quasi…
We report on long-term monitoring of anomalous X-ray pulsars (AXPs) using the Rossi X-ray Timing Explorer (RXTE). Using phase-coherent timing, we find a wide variety of behaviors among the sources, ranging from high stability (in 1E…
Precession in an accretion-powered pulsar is expected to produce characteristic variations in the pulse properties. Assuming surface intensity maps with one and two hotspots, we compute theoretically the periodic modulation of the mean…