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We report the multi-frequency observations of two pulsars: J1740+1000 and B1800-21, using the Giant Metrewave Radio Telescope and the Green Bank Telescope. The main aim of these observations was to estimate the flux density spectrum of…

High Energy Astrophysical Phenomena · Physics 2018-06-20 K. Rozko , K. M. Rajwade , W. Lewandowski , R. Basu , J. Kijak , D. R. Lorimer

The mechanisms of emission and changes in rotation frequency ('glitching') of the Vela pulsar (J0835-4510) are not well understood. Further insight into these mechanisms can be achieved by long-term studies of integrated pulse width, timing…

High Energy Astrophysical Phenomena · Physics 2016-03-21 J. L. Palfreyman , J. M. Dickey , S. P. Ellingsen , I. R. Jones , A. W. Hotan

Pulsars are known to emit non-thermal radio emission that is generally a power-law function of frequency. In some cases, a turnover is seen at frequencies around 100~MHz. Kijak et al. have reported the presence of a new class of ''Gigahertz…

High Energy Astrophysical Phenomena · Physics 2015-11-11 Kaustubh Rajwade , Duncan R Lorimer , Loren D Anderson

Pulsars are rotating neutron stars, sweeping the emission regions from the magnetic poles across our line of sight. Isolated neutron stars lose angular momentum through dipole radiation and (possibly) particle winds, hence they slow down…

Astrophysics · Physics 2009-11-07 R. G. Dodson , P. M. McCulloch , D. R. Lewis

Pulsars are rotating neutron stars, sweeping the emission regions from the magnetic poles across our line of sight. Isolated neutron stars lose angular momentum through dipole radiation and (possibly) particle winds, hence they slow down…

Astrophysics · Physics 2007-05-23 R Dodson , D. R. Lewis , P. M. McCulloch

We present the results of our radio interferometric observations of pulsars at 325 MHz and 610 MHz using the Giant Metrewave Radio Telescope (GMRT). We used the imaging method to estimate the flux densities of several pulsars at these radio…

High Energy Astrophysical Phenomena · Physics 2017-05-24 J. Kijak , R. Basu , W. Lewandowski , K. Rozko , M. Dembska

We present high-resolution multi-frequency single-pulse observations of the Vela pulsar, PSR B0833-45, aimed at studying micro-structure, phase-resolved intensity fluctuations and energy distributions at 1.41 and 2.30 GHz. We show that the…

Astrophysics · Physics 2009-11-07 M. Kramer , S. Johnston , W. van Straten

The main aim is to investigate the possibility of a high frequency turn-over in the radio spectrum of pulsars. Using the GMRT, multi-frequency flux density measurements of several candidate pulsars have been carried out and their spectra…

Astrophysics · Physics 2009-11-11 J. Kijak , Y. Gupta , K. Krzeszowski

We report on the spectral (pulse averaged) and timing analysis of the ~ 20 ksec observation of the X-ray binary pulsar Vela X-1 performed during the BeppoSAX Science Verification Phase. The source was observed in two different intensity…

We have observed a complex and continuous change in the integrated pulse profile of PSR B2217+47, manifested as additional components trailing the main peak. These transient components are detected over 6 years at $150$ MHz using the LOw…

The behaviour of the pulsar spectrum at high radio frequencies can provide decisive information about the nature of the radio emission mechanism. We report recent observations of a selected sample of pulsars at lambda=9mm (32 GHz) with the…

Astrophysics · Physics 2009-11-13 O. Loehmer , A. Jessner , M. Kramer , R. Wielebinksi , O. Maron

We studied the radio spectrum of PSR B1259-63 in an unique binary with Be star LS 2883 and showed that the shape of the spectrum depends on the orbital phase. We proposed a qualitative model which explains this evolution. We considered two…

Solar and Stellar Astrophysics · Physics 2015-06-12 Marta Dembska , Jarosław Kijak , Wojciech Lewandowski

We investigate a high frequency turn-over effect in radio spectra for pulsars with positive or flat spectral index. Using GMRT and Effelsberg observatory, we estimated the flux density to reconstruct pulsar spectra. We find objects that…

Astrophysics of Galaxies · Physics 2011-06-30 J. Kijak , W. Lewandowski , O. Maron , Y. Gupta , A. Jessner

In this paper we present recent Low Frequency Array (LOFAR) observations of the pulsar J1740+1000. We confirm that its spectrum has a turnover at 260 MHz, which is unusual for a typical pulsar. We argue that in this case interferometric…

High Energy Astrophysical Phenomena · Physics 2021-04-02 K. Rozko , J. Kijak , K. Chyzy , W. Lewandowski , T. Shimwell , S. S. Sridhar , M. Curylo , A. Krankowski , L. Blaszkiewicz

We present the first direct evidence for turn-over in pulsar radio spectra at high frequencies. Two pulsars are now shown to have a turn-over frequency > 1GHz. We also find some evidence that the peak frequency of turn-over in pulsar…

Astrophysics · Physics 2007-05-23 J. Kijak , Y. Gupta , K. Krzeszowski

We report the measurements of low radio frequency spectra of fourteen gigahertz-peaked spectra (GPS) pulsar candidates, between 300~MHz and 700~MHz, using the upgraded Giant Meterwave Radio Telescope. Combining newly collected measurements…

High Energy Astrophysical Phenomena · Physics 2025-04-14 K. Rożko , J. Kijak , R. Basu , P. Dabhade , W. Lewandowski

Low-frequency spectral studies of radio pulsars represent a key method for uncovering their emission mechanisms, magnetospheric structure, and signal interactions with the surrounding interstellar medium (ISM). In recent years, more…

Astrophysics of Galaxies · Physics 2025-10-13 Ting Yu , Zhongli Zhang , Hongyu Gong , Zhigang Wen

This paper presents an investigation of spectral properties of 10 millisecond pulsars (MSPs) discovered by the uGMRT, observed from 2017-2023 using band 3 (300-500 MHz) and 4 (550-750 MHz) of uGMRT. For these MSPs, we have reported a range…

High Energy Astrophysical Phenomena · Physics 2024-08-15 Rahul Sharan , Bhaswati Bhattacharyya , Sangita Kumari , Jayanta Roy , Ankita Ghosh

Braking index measurements offer the opportunity to explore the processes affecting the long-term spin evolution of pulsars and possible evolutionary connections between the various pulsar populations. For young pulsars the long-term trends…

High Energy Astrophysical Phenomena · Physics 2017-01-18 C. M. Espinoza , A. G. Lyne , B. W. Stappers

We study the radio spectrum of PSR B1259-63 orbiting around the Be star LS 2883 and show that the shape of the spectrum depends on the orbital phase. At frequencies below 3 GHz PSR B1259-63 flux densities are lower when measured near the…

Astrophysics of Galaxies · Physics 2012-01-04 J. Kijak , M. Dembska , W. Lewandowski , G. Melikidze , M. Sendyk
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