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We report detections of scintillation arcs for pulsars in globular clusters M5, M13 and M15 for the first time using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). From observations of these arcs at multiple epochs, we…

Astrophysics of Galaxies · Physics 2023-08-14 Dandan Zhang , Zhenzhao Tao , Mao Yuan , Jumei Yao , Pei Wang , Qijun Zhi , Weiwei Zhu , Xun Shi , Michael Kramer , Di Li , Lei Zhang , Guangxing Li

We present a new model for the Galactic distribution of free electrons. It (a) describes the distribution of the free electrons responsible for pulsar dispersion measures and thus can be used for estimating the distances to pulsars; (b)…

Astrophysics · Physics 2009-09-29 J. M. Cordes , T. J. W. Lazio

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

The stationary phase point (SPP) method in one-dimensional case is introduced to treat the diffractive scintillation. From weak scattering, where the SPP number N=1, to strong scattering (N$\gg$1), via transitional scattering regime…

Astrophysics · Physics 2014-10-13 C. M. Zhang

Radio waves propagating from distant pulsars in the interstellar medium (ISM), are refracted by electron density inhomogeneities, so that the intensity of observed pulses fluctuates with time. The theory relating the observed pulse…

Astrophysics · Physics 2009-11-10 Stanislav Boldyrev , Carl R. Gwinn

We have measured the properties of the diffractive scintillation toward the Vela pulsar under the extremely strong scattering conditions encountered at 660 MHz. We obtain a decorrelation bandwidth of $\nu_d = 244 \pm 4$ Hz and diffractive…

Astrophysics · Physics 2007-05-23 J. -P. Macquart , S. Johnston , M. Walker , D. Stinebring

Diffractive and refractive magnetospheric scintillations may allow a direct testing of the plasma inside the light cylinder. Unusual electrodynamics of the strongly magnetized electron-positron plasma allow separation of the magnetospheric…

Astrophysics · Physics 2009-10-31 Maxim Lyutikov

Pulse-shape discrimination (PSD) is usually achieved using the different fast and slow decay components of inorganic scintillators, such as BaF2, CsI:Tl, etc. However, LaBr3:Ce is considered to not possess different components at room…

Instrumentation and Detectors · Physics 2021-09-03 Jirong Cang , XinChao Fang , Zhi Zeng , Ming Zeng , Yinong Liu , Zhigang Sun , Ziyun Chen

We use VLBA+VLA observations to measure the sizes of the scatter-broadened images of 6 of the most heavily scattered known pulsars: 3 within the Galactic Centre (GC) and 3 elsewhere in the inner Galactic plane. By combining the measured…

Astrophysics of Galaxies · Physics 2017-08-30 J. Dexter , A. Deller , G. C. Bower , P. Demorest , M. Kramer , B. W. Stappers , A. G. Lyne , M. Kerr , L. G. Spitler , D. Psaltis , M. Johnson , R. Narayan

Free electrons in the interstellar medium cause frequency-dependent delays in pulse arrival times due to both scattering and dispersion. Multi-frequency measurements are used to estimate and remove dispersion delays. In this paper, we focus…

High Energy Astrophysical Phenomena · Physics 2015-06-23 M. T. Lam , J. M. Cordes , S. Chatterjee , T. Dolch

Radio wave scattering can cause severe reductions in detection sensitivity for surveys of Galactic and extragalactic fast ($\sim$ms duration) transients. While Galactic sources like pulsars undergo scattering in the Milky Way interstellar…

Astrophysics of Galaxies · Physics 2022-08-03 S. K. Ocker , J. M. Cordes , S. Chatterjee , M. R. Gorsuch

We consider the role of a propagation effect such as the stimulated Raman scattering on the polarization of radio pulses. When an intense electromagnetic wave with frequency close to the plasma frequency interacts with the plasma in the…

Astrophysics · Physics 2009-10-31 R. T. Gangadhara , H. Lesch , V. Krishan

Radio pulsars, as highly coherent point sources, serve as powerful probes of the ionized interstellar medium (IISM). Pulsar scintillation observations have revealed inverted arclets on the secondary spectrum, indicating quasilinearly…

Astrophysics of Galaxies · Physics 2026-04-14 Zhu Xu , Xun Shi

The search for compact components of strong ($S_{int} \ge 5$ Jy at 102.5 MHz) discrete radio sources from the Pushchino catalogue was carried out using the method of interplanetary scintillation. A total of 3620 sources were examined, and…

High Energy Astrophysical Phenomena · Physics 2022-07-18 S. A. Tyul'bashev , I. V. Chashei , I. A. Subaev , M. A. Kitaeva

Interstellar scattering causes pulsar profiles to grow asymmetrically, thus affecting the pulsar timing residuals, and is strongest at lower frequencies. Different Interstellar medium models predict different frequency ($\nu$) and…

High Energy Astrophysical Phenomena · Physics 2019-05-01 Karishma Bansal , G. B. Taylor , Kevin Stovall , Jayce Dowell

A subset of magnetic stars exhibit periodic radio pulses produced by the coherent electron cyclotron maser mechanism. These pulses are known to exhibit both temporal and spectral variations, which have been attributed to phenomena intrinsic…

Solar and Stellar Astrophysics · Physics 2026-04-21 J. S. Morgan , B. Das , H. E. Bignall

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…

The observing signals from pulsar are always influenced by the interstellar medium (ISM) scattering. In the lower frequency observation, the intensity profiles are broadened and the plane of polarization angle (PPA) curves are flattened by…

Solar and Stellar Astrophysics · Physics 2015-06-16 Abdujappar Rusul , Ali Esamdin , Xiao-Ping Zheng , Jian-Ping Yuan

Results from new observations of pulsars using the Ooty Radio Telescope (ORT) are used for investigating the structure of the Local Interstellar Medium (LISM). The observations show anomalous scintillation effects towards several nearby…

Astrophysics · Physics 2007-05-23 N. D. Ramesh Bhat , Yashwant Gupta , A. Pramesh Rao , P. B. Preethi

Waves propagating through a weakly scattering random medium show a pronounced branching of the flow accompanied by the formation of freak waves, i.e., extremely intense waves. Theory predicts that this strong fluctuation regime is…

Disordered Systems and Neural Networks · Physics 2013-11-05 S. Barkhofen , J. Metzger , R. Fleischmann , U. Kuhl , H. -J. Stoeckmann