Related papers: Highly-Magnetized Pulsars and Integral
Pulsars orbiting the Galactic center black hole, Sgr A*, would be potential probes of its mass, distance and spin, and may even be used to test general relativity. Despite predictions of large populations of both ordinary and millisecond…
(Abridged) Gamma-ray emission from pulsars has long been modeled using a vacuum dipole field. This approximation ignores changes in the field structure caused by the magnetospheric plasma and strong plasma currents. We present the first…
(abridged) Gamma-ray binaries are massive stars with compact object companions that are observed to emit most of their energy in the gamma-ray range. One of these binaries is known to contain a radio pulsar, PSR B1259-63. Synchrotron and…
Pulsars emit low-frequency radio waves through to high-energy gamma-rays that are generated anywhere from the surface out to the edges of the magnetosphere. Detecting correlated mode changes in the multi-wavelength emission is therefore key…
Extended very-high-energy $\gamma$-ray emission from middle-aged pulsars as revealed recently by several groundbased $\gamma$-ray experiments has strong implication on the transport of high-energy particles in the interstellar medium…
We report the first detection of pulsed X-ray emission from the young, energetic radio and Gamma-ray pulsar PSR B1706-44. We find a periodic signal at a frequency of f = 9.7588088 +/- 0.0000026 Hz (at epoch 51585.34104 MJD), consistent with…
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…
The core component width in normal pulsars, with periods ($P$) $>$ 0.1 seconds, measured at the half-power point at 1 GHz has a lower boundary line (LBL) which closely follows the $P^{-0.5}$ scaling relation. This result is of fundamental…
We report the detection of pulsed gamma-ray emission from the fast millisecond pulsars (MSPs) B1937+21 (also known as J1939+2134) and B1957+20 (J1959+2048) using 18 months of survey data recorded by the \emph{Fermi} Large Area Telescope…
My thesis deals with a fundamental question of high energy gamma-ray astronomy. Namely, I studied the cut-off shape of the Crab pulsar spectrum to distinguish between the leading scenarios for the pulsar models. Pulsars are celestial…
Recently, a precise (sub-arcsecond) localization of the repeating fast radio burst (FRB) 121102 has led to the discovery of persistent radio and optical counterparts, the identification of a host dwarf galaxy at a redshift of $z=0.193$, and…
We explore the possibilities for detecting pulsars that have ceased to radiate in the radio band. We consider two models: the model with hindered particle escape from the pulsar surface (first suggested by Ruderman and Sutherland 1975) and…
In July 2021, PKS 1510-089 exhibited a significant flux drop in the high-energy gamma-ray (by a factor 10) and optical (by a factor 5) bands and remained in this low state throughout 2022. Similarly, the optical polarization in the source…
Guillemot et al. recently reported the discovery of $\gamma$-ray pulsations from the 22.7ms pulsar (pulsar A) in the famous double pulsar system J0737-3039A/B. The $\gamma$-ray light curve (LC) of pulsar A has two peaks separated by…
Detecting and studying pulsars above a few GHz in the radio band is challenging due to the typical faintness of pulsar radio emission, their steep spectra, and the lack of observatories with sufficient sensitivity operating at high…
In the hard X-ray spectra of some X-ray binaries line features around 500 keV are detected. We interpret these as arising from pair annihilation in relativistic outflows leading to a significant Doppler shift of the frequencies of the…
Subpulse modulation has been regarded as one of the most insightful and intriguing aspects of pulsar radio emission. This phenomenon is generally explained by the presence of a carousel of sparks in the polar acceleration gap region that…
The nearly 100% linear polarization has been reported for a few fast radio bursts. This finding places severe limits on the emission mechanism. I argue that the totally polarized radiation could be generated in the course of relativistic…
We report on X-ray and gamma-ray observations of the millisecond pulsar B1937+21 taken with the Chandra X-ray Observatory, XMM-Newton, and the Fermi Large Area Telescope. The pulsar X-ray emission shows a purely non-thermal spectrum with a…
The process of electron positron pair annihilation, driven by strong fields (Inverse Schwinger mechanism) and high-frequency waves, is studied using the Dirac Heisenberg Wigner formalism. In an electron positron plasma, the presence of a…