English
Related papers

Related papers: Time variation in the low frequency spectrum of Ve…

200 papers

A radio source at the Galactic center Sgr A* is a prime supermassive black hole candidate and therefore key to developing our understanding of them. Time variations in the 230 GHz band flux of Sgr A* have been found with the Atacama Large…

High Energy Astrophysical Phenomena · Physics 2020-04-08 Yuhei Iwata , Tomoharu Oka , Masato Tsuboi , Makoto Miyoshi , Shunya Takekawa

We report on simultaneous X-ray and radio observations of the radio-mode-switching pulsar PSR B1822-09 with ESA's XMM-Newton and the WSRT, GMRT and Lovell radio telescopes. PSR B1822-09 switches between a radio-bright and radio-quiet mode,…

High Energy Astrophysical Phenomena · Physics 2017-01-18 W. Hermsen , L. Kuiper , J. W. T. Hessels , D. Mitra , J. M. Rankin , B. W. Stappers , G. A. E. Wright , R. Basu , A. Szary , J. van Leeuwen

The double pulsar PSR J0737-3039A/B displays short, 30 s eclipses that arise around conjunction when the radio waves emitted by pulsar A are absorbed as they propagate through the magnetosphere of its companion pulsar B. These eclipses…

We present the results from both the timing and spectroscopic analysis of the transient X-ray pulsar GS 1843+00 observed by the BeppoSAX satellite on 1997 April 4, when the source was at a luminosity of ~10^{37} erg s^{-1}. GS 1843+00 shows…

We investigate the spectral and temporal behavior of the high mass X-ray binary Vela X-1 during a phase of high activity, with special focus on the observed giant flares and off states. INTEGRAL observed Vela X-1 in a long almost…

The variability of the Vela pulsar (PSR B0833-45) corresponds to well-defined field statistics that vary with pulsar phase, ranging from Gaussian intensity statistics off-pulse to approximately power-law statistics in a transition region…

Astrophysics · Physics 2009-11-07 Iver H. Cairns , P. Das , P. A. Robinson , S. Johnston

Based on the free precession model of the isolated pulsar PSR B1828-11, Link & Epstein 2001) showed that the observed pulse durations require the radio beam to have a non-standard shape: the beam duration is larger for beam sweeps farthest…

Astrophysics · Physics 2009-11-07 Vahid Rezania

We present the results of the spectral and timing analyses of the accreting X-ray pulsar, 2S 1417-624, during the 2018 and 2021 outbursts with Insight-HXMT. We find that the pulse profiles in all energy bands exhibit clear double-peaked…

High Energy Astrophysical Phenomena · Physics 2025-06-17 Qi Liu , Lingda Kong , Can Güngör , Lorenzo Ducci , Long Ji , Wei Wang , Xiaohang Dai , Andrea Santangelo

The following results of dissertation are submitted for defense: 1. Precise measurements of coordinates and proper motion of the pulsar PSR 0329+54 using the VLBI method. 2. Establishing of the reason for the discrepancy between the…

Instrumentation and Methods for Astrophysics · Physics 2024-01-25 Alexander Evgenievich Rodin

We report on a 19 ks observation of the pulsar J1016-5857 with the Chandra X-ray Observatory. This "Vela-like" pulsar has rotation period 107 ms, characteristic age 21 kyr, and spin-down power 2.6e36 ergs/s. A relatively bright centrally…

Astrophysics · Physics 2009-11-10 F. Camilo , B. M. Gaensler , E. V. Gotthelf , J. P. Halpern , R. N. Manchester

We present 154 MHz Murchison Widefield Array imaging observations and variability information for a sample of pulsars. Over the declination range $-80^{\circ} < {\delta} < 10^{\circ}$ we detect 17 known pulsars with mean flux density…

We present a study of the radio and optical properties of the high-frequency peaker (HFP) blazar PKS 1614+051 at $z=3.21$ based on the data covering the time period of 1997-2024. The radio data are represented by the almost instantaneous…

With the ever-increasing sensitivity and timing baselines of modern radio telescopes, a growing number of pulsars are being shown to exhibit transitions in their rotational and radio emission properties. In many of these cases, the two are…

High Energy Astrophysical Phenomena · Physics 2022-05-11 B. Shaw , B. W. Stappers , P. Weltevrede , P. R. Brook , A. Karastergiou , C. A. Jordan , M. J. Keith , M. Kramer , A. G. Lyne

We have detected a strong deflection of radio waves from the pulsar PSR B0834+06 in scintillation observations. Interference between the undeflected pulsar image and deflected subimages allows single dish interferometry of the interstellar…

Recent observations of the Vela pulsar have revealed a peculiar connection of its emission in the soft X-ray and radio ranges. We suggest the model of the radio pulse formation in the Vela pulsar, develop the theory of the radio photon…

High Energy Astrophysical Phenomena · Physics 2009-11-13 S. A. Petrova

We have used archival 74 MHz VLA data spanning the last 15 years in combination with new data from the Long Wavelength Demonstrator Array (LWDA) and data from the literature covering the last 50 years to explore the evolution of Cas A at…

Astrophysics of Galaxies · Physics 2015-05-13 J. F. Helmboldt , N. E. Kassim

In this letter we present the results of a wavelet analysis of the radio light curve of the BL Lac Object PKS B0048-097 from the University of Michigan Radio Astronomy Observatory monitoring program at 8GHz during twenty-five years, from…

Astrophysics · Physics 2009-11-11 M. Kadler , P. A. Hughes , E. Ros , M. F. Aller , H. D. Aller

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…

High Energy Astrophysical Phenomena · Physics 2023-07-26 Samuel J. McSweeney , Lisa Smith , N. D. Ramesh Bhat , Geoff Wright

We present results from X-ray and radio observations of the recently discovered young Vela-like pulsar PSR J2021+3651, which is coincident with the EGRET gamma-ray source GeV 2020+3658. A 19.0-ks Chandra ACIS-S observation has revealed a…

(Abridged) We present high-resolution Chandra X-ray observations of PSR B0833-45, the 89 ms pulsar associated with the Vela supernova remnant. We have acquired two observations separated by one month to search for changes in the pulsar and…

Astrophysics · Physics 2009-10-31 D. J. Helfand , E. V. Gotthelf , J. P. Halpern