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相关论文: Turn-over in pulsar spectra above 1 GHz

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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…

天体物理学 · 物理学 2009-11-11 J. Kijak , Y. Gupta , K. Krzeszowski

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…

星系天体物理 · 物理学 2011-06-30 J. Kijak , W. Lewandowski , O. Maron , Y. Gupta , A. Jessner

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…

高能天体物理现象 · 物理学 2015-11-11 Kaustubh Rajwade , Duncan R Lorimer , Loren D Anderson

We have collected pulsar flux density observations and compiled spectra of 281 objects. The database of Lorimer et al. (\cite{lorimer}) has been extended to frequencies higher than 1.4 GHz and lower than 300 MHz. Our results show that above…

天体物理学 · 物理学 2009-10-31 Olaf Maron , Jaroslaw Kijak , Michael Kramer , Richard Wielebinski

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…

天体物理学 · 物理学 2009-11-13 O. Loehmer , A. Jessner , M. Kramer , R. Wielebinksi , O. Maron

The analytical expression for frequency of the maximum of radio emission intensity in pulsars with free electron emission from the stellar surface has been found. We have explained the correlation, known from observations, between the…

太阳与恒星天体物理 · 物理学 2015-06-11 V. M. Kontorovich , A. B. Flanchik

We report the flux measurement of the Vela like pulsar B1800-21 at the low radio frequency regime over multiple epochs spanning several years. The spectrum shows a turnover around the GHz frequency range and represents a typical example of…

高能天体物理现象 · 物理学 2016-02-22 Rahul Basu , Karolina Rożko , Wojciech Lewandowski , Jarosław Kijak , Marta Dembska

We have analyzed the polarization properties of pulsars at an observing frequency of 4.9 GHz. Together with low frequency data, we are able to trace polarization profiles over more than three octaves into an interesting frequency regime. At…

天体物理学 · 物理学 2007-05-23 A. von Hoensbroech , J. Kijak , A. Krawczyk

In their catalogue of pulsars' radio spectra, Swainston et al. (2022, PASA, 39, e056) distinguish between five different forms of these spectra: those that can be fitted with (i) a simple power law, (ii) a broken power law, (iii) a…

高能天体物理现象 · 物理学 2024-03-29 Houshang Ardavan

In this paper we present the first observations of a large sample of millisecond pulsars at frequencies of 2.7 GHz and 4.9 GHz. Our new flux measurements extend the known spectra for millisecond pulsars to the highest frequencies to date.…

天体物理学 · 物理学 2009-10-31 M. Kramer , C. Lange , D. R. Lorimer , D. C. Backer , K. M. Xilouris , A. Jessner , R. Wielebinski

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…

高能天体物理现象 · 物理学 2018-06-29 Pablo Torne

Motivated by recent results on the location of the radio emission in pulsar magnetospheres, we have developed a model which can account for the large diversity found in the average profile shapes of pulsars. At the centre of our model lies…

天体物理学 · 物理学 2009-11-13 A. Karastergiou , S. Johnston

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…

高能天体物理现象 · 物理学 2025-04-14 K. Rożko , J. Kijak , R. Basu , P. Dabhade , W. Lewandowski

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…

太阳与恒星天体物理 · 物理学 2015-06-15 Samuel D. Bates , Duncan R. Lorimer , Joris P. W. Verbiest

At present three pulsars are known which clearly show a strongly increasing degree of circular polarization with frequency. As this is accompanied by a smooth decrease of linear polarization, we investigate, if this observation can be…

天体物理学 · 物理学 2007-05-23 Alexis von Hoensbroech , Harald Lesch

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…

高能天体物理现象 · 物理学 2017-05-24 J. Kijak , R. Basu , W. Lewandowski , K. Rozko , M. Dembska

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…

高能天体物理现象 · 物理学 2018-02-07 Rahul Basu , Karolina Rożko , Jarosław Kijak , Wojciech Lewandowski

Pulsars are famed for their rotational clock-like stability and their highly-repeatable pulse shapes. However, it has long been known that there are unexplained deviations (often termed "timing noise") from the rate at which we predict…

星系天体物理 · 物理学 2010-06-29 Andrew Lyne , George Hobbs , Michael Kramer , Ingrid Stairs , Ben Stappers

We have observed a total of 67 pulsars at five frequencies ranging from 243 to 3100 MHz. Observations at the lower frequencies were made at the Giant Metre Wave Telescope in India and those at higher frequencies at the Parkes Telescope in…

天体物理学 · 物理学 2009-11-13 Simon Johnston , Aris Karastergiou , Dipanjan Mitra , Yashwant Gupta

On the basis of the unified model of compact radio sources, the dependence of a turnover frequency in the smoothed radio spectrum of a pulsar upon the ratio of the dispersion measure to the period of a pulsar is obtained. This relation is…

天体物理学 · 物理学 2010-05-19 F. V. Prigara
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