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In separate series of observations of the Crab pulsar, pulse broadening due to scattering was measured at 111 MHz, and variations of dispersion due to pulse delay were measured at higher radio frequencies. In a remarkable event lasting 200…

天体物理学 · 物理学 2009-11-13 A. Kuzmin , B. Ya. Losovsky , C. A. Jordan , F. Graham Smith

We report on Westerbork Synthesis Radio Telescope observations of the Crab pulsar at 350 MHz from 2012 November 24 until 2015 June 21. During this period we consistently observe variations in the pulse profile of the Crab. Both variations…

高能天体物理现象 · 物理学 2018-12-19 L. N. Driessen , G. H. Janssen , C. G. Bassa , B. W. Stappers , D. R. Stinebring

The high sensitivity and wide frequency coverage of the Murchison Widefield Array allow for the measurement of the spectral scaling of the pulsar scattering timescale, $\alpha$, from a single observation. Here we present three case studies…

高能天体物理现象 · 物理学 2019-04-17 F. Kirsten , N. D. R. Bhat , B. W. Meyers , J. -P. Macquart , S. E. Tremblay , S. M. Ord

We report observations of Crab giant pulses made with the Australia Telescope Compact Array and a baseband recorder system, made simultaneously at two frequencies, 1300 and 1470 MHz. These observations were sensitive to pulses with…

天体物理学 · 物理学 2009-11-13 N. D. Ramesh Bhat , Steven J. Tingay , Haydon S. Knight

Giant pulses from Crab pulsar were observed together with Radioastron space radiotelescope, Global EVN radio telescopes and Kvazar-KVO VLBI stations to study the scattering effects in the ISM. Five observing sessions were conducted at 18 cm…

太阳与恒星天体物理 · 物理学 2015-05-06 Alexey Rudnitskiy , Mikhail Popov , Vladimir Soglasnov

In 1997 October daily monitoring observations of the Crab pulsar at 327 MHz and 610 MHz with an 85ft telescope in Green Bank, WV showed a jump in the dispersion measure by 0.1 cm$^{-3}$ pc. Pulses were seen simultaneously at both old and…

天体物理学 · 物理学 2016-08-30 D. C. Backer , T. Wong , J. Valanju

The Crab pulsar emits across a large part of the electromagnetic spectrum. Determining the time delay between the emission at different wavelengths will allow to better constrain the site and mechanism of the emission. We have…

天体物理学 · 物理学 2009-11-13 T. Oosterbroek , I. Cognard , A. Golden , P. Verhoeve , D. D. E. Martin , C. Erd , R. Schulz , J. A. Stuewe , A. Stankov , T. Ho

The stability of the optical pulse of the Crab pulsar is analyzed based on the 1 $\mu$s resolution observations with the Russian 6-meter and William Hershel telescopes equipped with different photon-counting detectors. The search for the…

天体物理学 · 物理学 2007-09-18 S. Karpov , G. Beskin , A. Biryukov , V. Plokhotnichenko , V. Debur , A. Shearer

Using archival data from the 42 foot telescope at the Jodrell Bank Observatory, we produce daily stacks of aligned giant pulses for the Crab pulsar, to study changes to the daily profiles between April 2012 to December 2016. From these, we…

We present a large survey of giant pulses from the Crab Pulsar as observed with the first station of the Long Wavelength Array. Automated methods for detecting giant pulses at low frequencies where scattering becomes prevalent are also…

太阳与恒星天体物理 · 物理学 2016-10-05 T. Eftekhari , K. Stovall , J. Dowell , F. K. Schinzel , G. B. Taylor

The fine structure and the variations of the optical pulse shape and phase of the Crab pulsar are studied on various time scales. The observations have been carried out on 4-m William Hershel and 6-m BTA telescopes with APD photon counter,…

天体物理学 · 物理学 2008-11-26 S. Karpov , G. Beskin , A. Biryukov , V. Debur , V. Plokhotnichenko , M. Redfern , A. Shearer

Simultaneous dual-frequency observations of giant pulses from the Crab pulsar were performed at the frequencies of 61 and 111 MHz. It is shown that scattering of giant pulses from the Crab pulsar occurs at thick, and not at thin screen.

天体物理学 · 物理学 2007-09-13 Alexander A. Ershov

We present a robust approach to incorporating models for the time-variable broadening of the pulse profile due to scattering in the ionized interstellar medium into profile-domain pulsar timing analysis. We use this approach to…

天体物理仪器与方法 · 物理学 2017-04-12 L. Lentati , M. Kerr , S. Dai , R. M. Shannon , G. Hobbs , S. Oslowski

We present simulations of scattering phenomena which are important in pulsar observations, but which are analytically intractable. The simulation code, which has also been used for solar wind and atmospheric scattering problems, is…

星系天体物理 · 物理学 2015-05-19 W. A. Coles , B. J. Rickett , J. J. Gao , G. Hobbs , J. P. W. Verbiest

This paper describes a comprehensive measurement model for the error budget of pulse arrival times with emphasis on intrinsic pulse jitterand plasma propagation effects (particularly interstellar scattering), which are stochastic in time…

天体物理仪器与方法 · 物理学 2010-10-20 J. M. Cordes , R. M. Shannon

Our high-time-resolution observations reveal that individual main pulses from the Crab pulsar contain one or more short-lived microbursts. Both the energy and duration of bursts measured above 1 GHz can vary dramatically in less than a…

高能天体物理现象 · 物理学 2015-05-19 Jared H. Crossley , Jean A. Eilek , Timothy H. Hankins , Jeff S. Kern

A pulsar's pulse profile gets broadened at low frequencies due to dispersion along the line of sight or due to multi-path propagation. The dynamic nature of the interstellar medium makes both of these effects time-dependent and introduces…

The Crab Pulsar's radio emission is unusual, consisting predominantly of giant pulses, with durations of about a micro-second but structure down to the nano-second level, and brightness temperatures of up to $10^{37}\,$K. It is unclear how…

VLBI observations of the Crab pulsar with the 64-m radio telescope at Kalyazin (Russia) and the 46-m radio telescope of the Algonquin Radio Observatory (Canada) at 2.2 GHz and single-dish observations of the millisecond pulsar B1937+21 with…

天体物理学 · 物理学 2009-11-13 V. I. Kondratiev , M. V. Popov , V. A. Soglasnov , Y. Y. Kovalev , N. Bartel , W. Cannon , A. Yu. Novikov

The Crab pulsar has striking radio emission properties, with the two dominant pulse components -- the main pulse and the interpulse -- consisting entirely of giant pulses. The emission is scattered in both the Crab nebula and the…

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