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Related papers: Long-term scintillation studies of EPTA pulsars. I…

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We propose to use pulsar scintillation measurements to test predictions of alternative theories of gravity. Comparing to single-path pulsar timing measurements, the scintillation measurements can achieve a factor of 10^5 improvement in…

General Relativity and Quantum Cosmology · Physics 2017-05-03 Huan Yang , Atsushi Nishizawa , Ue-Li Pen

To assist with the commissioning (Jiang et al. 2019) of the Five-hundred-meter Aperture Spherical radio Telescope (FAST), we performed a pulsar search, with the primary goal of developing and testing the pulsar data acquisition and…

In this work we study variations in the parabolic scintillation arcs of the binary millisecond pulsar PSR J1643-1224 over five years using the Large European Array for Pulsars (LEAP). The 2D power spectrum of scintillation, called the…

We report measurements of time delays of up to 8 minutes in the centimeter wavelength variability patterns of the intra-hour scintillating quasar PKS 1257-326 as observed between the VLA and the ATCA on three separate epochs. These time…

We present multi-wavelength scatter broadening observations of 47 pulsars, made with the Giant Metre-wave Radio Telescope (GMRT), Ooty Radio Telescope (ORT) and Long Wavelength Array (LWA). The GMRT observations have been made in the phased…

High Energy Astrophysical Phenomena · Physics 2017-09-13 M. A. Krishnakumar , Bhal Chandra Joshi , P. K. Manoharan

Interstellar scintillation can be used to probe transverse sizes of radio sources on scales inaccessible to the nominal resolution of any terrestrial telescope, e.g. $\lesssim 10^{-6}$ arc sec. Methodology is presented that exploits this…

Astrophysics · Physics 2007-05-23 J. M. Cordes

Radio pulsars scintillate because their emission travels through the ionized interstellar medium via multiple paths, which interfere with each other. It has long been realized that the scattering screens responsible for the scintillation…

High Energy Astrophysical Phenomena · Physics 2018-05-25 Robert Main , I-Sheng Yang , Victor Chan , Dongzi Li , Fang Xi Lin , Nikhil Mahajan , Ue-Li Pen , Keith Vanderlinde , Marten H. van Kerkwijk

One contribution to the time resolution of a scintillation detector is the signal time spread due to path length variations of the detected photons from a point source. In an experimental study a rectangular scintillator was excited by…

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 present the measurements of scatter broadening time-scales ($\tau_{sc}$) for 124 pulsars at 327 MHz, using the upgraded Ooty Radio Telescope (ORT). These pulsars lie in the dispersion measure range of 37 $-$ 503 pc cm$^{-3}$ and…

High Energy Astrophysical Phenomena · Physics 2017-06-20 M. A. Krishnakumar , Dipanjan Mitra , Arun Naidu , Bhal Chandra Joshi , P. K. Manoharan

Giant pulses emitted by PSR B1937+21 are bright, intrinsically impulsive bursts. Thus, the observed signal from a giant pulse is a noisy but direct measurement of the impulse response from the ionized interstellar medium. We use this fact…

High Energy Astrophysical Phenomena · Physics 2023-10-12 Nikhil Mahajan , Marten H. van Kerkwijk

We report the discovery of fast, frequency-dependent intensity variations from the scintillating intra-day variable quasar J1819+3845 at a wavelength of 21cm which resemble diffractive interstellar scintillations observed in pulsars. The…

Astrophysics · Physics 2009-11-11 Jean-Pierre Macquart , Ger de Bruyn

I use a method based on interstellar scintillations for discerning information about source sizes on scales less than one micro-arc sec. I use a comprehensive model for a pulsar signal, scintillated amplitude modulated noise, that includes…

Astrophysics · Physics 2007-05-23 J. M. Cordes

We investigate the radio emission behaviour of PSR B0823+26, a pulsar which is known to undergo pulse nulling, using an 153-d intensive sequence of observations. The pulsar is found to exhibit both short (~min) and unusually long-term…

High Energy Astrophysical Phenomena · Physics 2015-06-11 N. J. Young , B. W. Stappers , P. Weltevrede , A. G. Lyne , M. Kramer

We study statistical properties of stochastic variations in pulse arrival times, timing noise, in radio pulsars using a new analysis method applied in the time domain. The method proceeds in two steps. First, we subtract low-frequency…

High Energy Astrophysical Phenomena · Physics 2015-06-11 Steve Price , Bennett Link , Steve Shore , David Nice

The analysis of variations in the emission intensity of the pulsar B0950+08 from 2014 to 2022 with scales from minutes to years was carried out. The observations were obtained in a round-the-clock daily survey conducted on the Large Phased…

High Energy Astrophysical Phenomena · Physics 2025-03-19 T. V. Smirnova , M. O. Toropov , S. A. Tyul'bashev

The recent discovery of ultra-long wavelength gravitational waves through the advent of pulsar timing arrays (PTA) has opened up new avenues for fundamental science. Here we show that every PTA source will be diffractively lensed by…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-04 Dylan L. Jow , Ue-Li Pen

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…

Instrumentation and Methods for Astrophysics · Physics 2010-10-20 J. M. Cordes , R. M. Shannon

We present here a method to study the distribution of electron density fluctuations in pulsar directions as well as to estimate pulsar distances. The method, based on a simple two-component model of the scattering medium discussed by Gwinn…

Astrophysics · Physics 2009-10-30 A. A. Deshpande , R. Ramachandran

The frequency dependence of radio pulse arrival times provides a probe of structures in the intervening media. Demorest et al. 2013 was the first to show a short-term (~100-200 days) reduction in the electron content along the line of sight…