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The pulsed radiation from PSR B0833-45 (Vela) has a phased-averaged spectral energy distribution (SED) of an apparently simple structure across a wide energy range, from optical light to hard gamma-rays. However, the Vela pulses in narrow…

High Energy Astrophysical Phenomena · Physics 2017-08-07 Bronisław Rudak , Jarosław Dyks

The Parkes telescope has been monitoring 286 radio pulsars approximately monthly since 2007 at an observing frequency of 1.4 GHz. The wide dispersion measure (DM) range of the pulsar sample and the uniformity of the observing procedure make…

High Energy Astrophysical Phenomena · Physics 2021-01-06 H. Kumamoto , S. Dai , S. Johnston , M. Kerr , R. M. Shannon , P. Weltevrede , C. Sobey , R. N. Manchester , G. Hobbs , K. Takahashi

The Vela pulsar (J0835-4510) is known to exhibit variations in Faraday rotation and dispersion on multi-decade timescales due to the changing sightline through the surrounding Vela supernova remnant and the Gum Nebula. Until now, variations…

High Energy Astrophysical Phenomena · Physics 2024-11-04 C. P. Lee , N. D. R. Bhat , M. Sokolowski , B. W. Meyers , A. Magro

We report the results of the spectral and timing analysis of observations of the Vela pulsar with the Chandra X-ray Observatory. The spectrum shows no statistically significant spectral lines in the observed 0.25--8.0 keV band. It consists…

Recently published results \citep{kijak2011b} indicated the evidence for a new aspect in radio pulsars spectra. We studied the radio spectrum of PSR B1259-63 in an unique binary with Be star LS 2883 and showed that this pulsar undergoes a…

Astrophysics of Galaxies · Physics 2012-12-06 M. Dembska , J. Kijak , W. Lewandowski

We explore the long-term evolution of the spin period of the High Mass X-ray Binary (HMXB) pulsar Vela X-1 over a period of 46 yr. Our analysis indicates nearly periodic variations in the spin period of the pulsar on time-scales of about…

High Energy Astrophysical Phenomena · Physics 2022-04-26 Amar Deo Chandra , Jayashree Roy , P. C. Agrawal , Manojendu Choudhury

We report the detailed spectral measurements over a wide frequency range of three pulsars: J1741-3016, J1757-2223 and J1845-0743, using the Giant Metrewave Radio Telescope, which allowed us to identify them as a new gigahertz-peaked spectra…

High Energy Astrophysical Phenomena · Physics 2022-01-11 K. Rożko , R. Basu , J. Kijak , W. Lewandowski

Pulsars show two classes of rotational irregularities that can be used to understand neutron-star interiors and magnetospheres: glitches and timing noise. Here we present an analysis of the Vela pulsar spanning nearly 21 yr of observation…

High Energy Astrophysical Phenomena · Physics 2016-04-27 R. M. Shannon , L. T. Lentati , M. Kerr , S. Johnston , G. Hobbs , R. N. Manchester

We present multi-frequency scatter broadening evolution of 29 pulsars observed with the LOw Frequency ARray (LOFAR) and Long Wavelength Array (LWA). We conducted new observations using LOFAR Low Band Antennae (LBA) as well as utilized the…

High Energy Astrophysical Phenomena · Physics 2019-06-26 M. A. Krishnakumar , Yogesh Maan , Bhal Chandra Joshi , P. K. Manoharan

The Vela pulsar is one of the most exciting gamma-ray sources and has been at the forefront of high-energy pulsar science since the detection of gamma-ray pulsations at the radio period by SAS-2 in 1975. With the unprecedented angular…

High Energy Astrophysical Phenomena · Physics 2009-12-22 T. J. Johnson , Ö. Çelik , M. Kerr , A. K. Harding , G. A. Caliandro

We present high time resolution observations of single pulses from the Vela pulsar (PSR B0833-45) made with a baseband recording system at observing frequencies of 660 and 1413 MHz. We have discovered two startling features in the 1413 MHz…

Astrophysics · Physics 2009-11-06 Simon Johnston , Willem van Straten , Michael Kramer , Matthew Bailes

We conducted radio interferometric observations of six pulsars at 610 MHz using the Giant Metrewave Radio Telescope (GMRT). All these objects were claimed or suspected to be the gigahertz-peaked spectra (GPS) pulsars. For a half of the…

High Energy Astrophysical Phenomena · Physics 2015-06-24 M. Dembska , R. Basu , J. Kijak , W. Lewandowski

Three periastron passages of the PSR B1259$-$63/LS 2883 binary system, consisting of a 48 ms rotation-powered pulsar and a $\sim30$ M$_{\odot}$ Be star, have been observed by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space…

High Energy Astrophysical Phenomena · Physics 2018-08-15 T. J. Johnson , K. S. Wood , M. Kerr , R. H. D. Corbet , C. C. Cheung , P. S. Ray , N. Omodei

We report on broad multi-wavelength observations of the 2010-2011 periastron passage of the gamma-ray loud binary system PSR B1259-63. High resolution interferometric radio observations establish extended radio emission trailing the…

(Abridged) We investigate the flux density variability and changes in the parsec-scale radio structure of the flat spectrum radio quasar PKS 1510-089. This source was target of multi-epoch VLBI and Space-VLBI observations at 4.8, 8.4 and 22…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 M. Orienti , T. Venturi , D. Dallacasa , F. D'Ammando , M. Giroletti , G. Giovannini , S. Vercellone , M. Tavani

The major programme for observing young, non-recycled pulsars with the Parkes telescope has transitioned from a narrow-band system to an ultra-wideband system capable of observing between 704 and 4032 MHz. We report here on the initial two…

High Energy Astrophysical Phenomena · Physics 2021-02-10 Simon Johnston , C. Sobey , S. Dai , M. Keith , M. Kerr , R. N. Manchester , L. S. Oswald , A. Parthasarathy , R. M. Shannon , P. Weltevrede

The flux density spectra of radio pulsars are known to be steep and, to first order, described by a power-law relationship of the form S_{\nu} \propto \nu^{\alpha}, where S_{\nu} is the flux density at some frequency \nu and \alpha is the…

Solar and Stellar Astrophysics · Physics 2015-06-15 Samuel D. Bates , Duncan R. Lorimer , Joris P. W. Verbiest

In this paper we present results from flux density measurements for 21 pulsars over a wide frequency range, using the Giant Metrewave Radio Telescope (GMRT) and the Effelsberg telescope. Our sample was a set of mostly newly discovered…

High Energy Astrophysical Phenomena · Physics 2014-10-31 M. Dembska , J. Kijak , A. Jessner , W. Lewandowski , B. Bhattacharyya , Y. Gupta

We compare the noise in interferometric measurements of the Vela pulsar from ground- and space-based antennas with theoretical predictions. The noise depends on both the flux density and the interferometric phase of the source. Because the…

Individual pulses from pulsars have intensity-phase profiles that differ widely from pulse to pulse, from the average profile, and from phase to phase within a pulse. Widely accepted explanations for pulsar radio emission and its time…

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