Modelling of the radio spectrum evolution in the binary pulsar B1259−63

Dembska, M.; Kijak, J.; Koralewska, O.; Lewandowski, Wojciech; Melikidze, George I.; Rożko, Karolina

doi:10.1007/s10509-015-2447-8

Cited by 8 publications

(9 citation statements)

References 24 publications

(34 reference statements)

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“…The observations were conducted using the Giant Metrewave Radio Telescope (GMRT) located near Pune, India. The observations were primarily carried out using standard interferometric schemes with strategically spaced calibrators interspersed with the sources as detailed in Dembska et al (2015a). In one pulsar J1747−2958 we observed simultaneously in the phased-array mode along with the interferometric observations (Basu et al 2016) to look for pulsed emission.…”

Section: Observing Detailsmentioning

confidence: 99%

“…These sources are called gigahertz-peaked spectrum (GPS) pulsars and only a handful of such sources are known. A systematic search for GPS pulsars have been conducted since the initial discovery (Kijak et al 2011a(Kijak et al ,b, 2013Dembska et al 2014Dembska et al , 2015aBasu et al 2016;Kijak et al 2017;Jankowski et al 2017) with seventeen pulsars confirmed to exhibit GPS behaviour. The GPS pulsars are usually associated with young energetic sources which are found in peculiar environments like Pulsar wind nebulae (PWN), HII regions, Supernova remnants (SNR), etc.…”

Section: Introductionmentioning

confidence: 99%

“…In such cases the standard pulsar observation techniques results in serious underestimation of the pulsar flux density due to the presence of long scattering tails. Dembska et al (2015a) showed that interferometric imaging provides the only possible way to securely measure the flux density in highly scattered pulsar profiles. Additionally, Basu et al (2016) also demonstrated that the interferometric techniques were vastly superior to the standard pulsar flux density measurements from a phased-array owing to the possibility of self calibration.…”

Section: Introductionmentioning

confidence: 99%

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Gigahertz-peaked spectra pulsars in Pulsar Wind Nebulae

Basu¹,

Rożko²,

Kijak³

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We have carried out a detailed study of the spectral nature of six pulsars surrounded by Pulsar wind nebulae (PWN). The pulsar flux density were estimated using the interferometric imaging technique of the Giant Metrewave Radio Telescope at three frequencies 325 MHz, 610 MHz and 1280 MHz. The spectra showed a turnover around gigahertz frequency in four out of six pulsars. It has been suggested that the gigahertz peaked spectra (GPS) in pulsars arises due to thermal absorption of the pulsar emission in surrounding medium like PWN, HII regions, Supernova remnants, etc. The relatively high incidence of GPS behaviour in pulsars surrounded by PWN impart further credence to this view. The pulsar J1747−2958 associated with the well known Mouse nebula was also observed in our sample and exhibited GPS behaviour. The pulsar was detected as a point source in the high resolution images. However, the pulsed emission was not seen in the phased array mode. It is possible that the pulsed emission was affected by extreme scattering causing considerable smearing of the emission at low radio frequencies. The GPS spectra were modeled using the thermal free-free absorption and the estimated absorber properties were largely consistent with PWN. The spatial resolution of the images made it unlikely that the point source associated with J1747−2958 was the compact head of the PWN, but the synchrotron self-absorption seen in such sources was a better fit to the estimated spectral shape.

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Section: Observing Detailsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Gigahertz-peaked spectra pulsars in Pulsar Wind Nebulae

Basu¹,

Rożko²,

Kijak³

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…It has been proposed that the GPS phenomenon occurs because of thermal free-free absorption in dense ionized material surrounding a pulsar, for example in a pulsar wind nebula, molecular cloud, or supernova remnant (Lewandowski et al 2015;Rajwade et al 2016), or when the radio emission from a pulsar passes through the dense wind of a binary companion. In the case of the pulsar J1302-6350 (B1259-63), the only known radio pulsar with a main-sequence Be star companion, the pulsed flux density and its spectrum was found to vary with orbital phase (Johnston et al 1996;Kijak et al 2011a;Dembska et al 2015a). There is considerable discussion about the spectral shape exhibited by GPS pulsars and their spectra have been modelled by broken power law, log-parabolic (Bates et al 2013;Dembska et al 2014) and free-free absorption models by different authors.…”

Section: Introductionmentioning

confidence: 99%

Spectral properties of 441 radio pulsars

Jankowski

Straten

Keane

et al. 2017

Monthly Notices of the Royal Astronomical Society

201

193

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We present a study of the spectral properties of 441 pulsars observed with the Parkes radio telescope near the centre frequencies of 728, 1382 and 3100 MHz. The observations at 728 and 3100 MHz were conducted simultaneously using the dual-band 10-50cm receiver. These high-sensitivity, multi-frequency observations provide a systematic and uniform sample of pulsar flux densities. We combine our measurements with spectral data from the literature in order to derive the spectral properties of these pulsars. Using techniques from robust regression and information theory we classify the observed spectra in an objective, robust and unbiased way into five morphological classes: simple or broken power law, power law with either low or high-frequency cutoff and log-parabolic spectrum. While about 79% of the pulsars that could be classified have simple power law spectra, we find significant deviations in 73 pulsars, 35 of which have curved spectra, 25 with a spectral break and 10 with a low-frequency turn-over. We identify 11 gigahertz-peaked spectrum (GPS) pulsars, with 3 newly identified in this work and 8 confirmations of known GPS pulsars; 3 others show tentative evidence of GPS, but require further low-frequency measurements to support this classification. The weighted mean spectral index of all pulsars with simple power law spectra is −1.60 ± 0.03. The observed spectral indices are well described by a shifted log-normal distribution. The strongest correlations of spectral index are with spin-down luminosity, magnetic field at the light-cylinder and spin-down rate. We also investigate the physical origin of the observed spectral features and determine emission altitudes for three pulsars.

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“…They showed that the physical properties of certain of environments suggest that thermal absorption can cause the observed spectra to turnover at gigahertz frequencies. The difference between the binary system and a typical GPS pulsar is that for PSR B1259−63 the intensity of the effect changes due to variable amount of matter that the pulsar radiation has to pass through, (Dembska et al 2015b), whereas for the isolated pulsar the geometry of the absorber remains static, producing a stable, GPS-type spectrum. Similar approach was also used by Rajwade, Lorimer & Anderson (2016a) for a selected sample of six pulsars and by Basu et al (2016) to explain the apparent variability of the spectra in PSR B1800−21.…”

Section: Introductionmentioning

confidence: 99%

Gigahertz-peaked Spectra Pulsars and Thermal Absorption Model

Kijak

Basu

Lewandowski

et al. 2017

ApJ

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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 frequencies. The analysis of the shapes of the pulsar spectra allowed us to identify five new gigahertz-peaked spectra (GPS) pulsars. Using the hypothesis that the spectral turnovers are caused by thermal free-free absorption in the interstellar medium, we modeled the spectra of all known objects of this kind. Using the model, we were able to put some observational constrains on the physical parameters of the absorbing matter, which allows us to distinguish between the possible sources of absorption. We also discuss the possible effects of the existence of GPS pulsars on future search surveys, showing that the optimal frequency range for finding such objects would be from a few GHz (for regular GPS sources) to possibly 10 GHz for pulsars and radio-magnetars exhibiting very strong absorption.

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Modelling of the radio spectrum evolution in the binary pulsar B1259−63

Cited by 8 publications

References 24 publications

Gigahertz-peaked spectra pulsars in Pulsar Wind Nebulae

Gigahertz-peaked spectra pulsars in Pulsar Wind Nebulae

Spectral properties of 441 radio pulsars

Gigahertz-peaked Spectra Pulsars and Thermal Absorption Model

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