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We present a timing and scintillation study of the young Galactic halo pulsar PSR J1740+1000 using observations from the Nanshan, FAST, and Parkes radio telescopes. From timing analysis, we measure the pulsar's proper motion for the first…

Astrophysics of Galaxies · Physics 2026-03-02 J. M. Yao , F. F. Kou , J. P. Yuan , Y. Wei , William A. Coles , Richard N. Manchester , N. Wang , S. Q. Wang , W. M. Yan

We consider the time derivatives of the period $P$ of pulsars at the Galactic Center due to variations in their orbital Doppler shifts. We show that in conjunction with a measurement of a pulsar's proper motion and its projected separation…

Instrumentation and Methods for Astrophysics · Physics 2015-06-19 Pierre Christian , Abraham Loeb

We use cyclic spectroscopy to directly measure the scintillation parameter $C_1$ for the millisecond pulsar B1937+21. This marks the first time this constant has been measured for any pulsar without assuming a pulse broadening function…

High Energy Astrophysical Phenomena · Physics 2026-05-27 Jacob E. Turner

X-ray photons coming from an X-ray point source not only arrive at the detector directly, but also can be strongly forward-scattered by the interstellar dust along the line of sight (LOS), leading to a detectable diffuse halo around the…

High Energy Astrophysical Phenomena · Physics 2015-10-23 Junjie Mao , Zhixing Ling , Shuang-Nan Zhang

Extreme Scattering Events are radio-wave lensing events caused by AU-sized concentrations of ionised gas. Although they were discovered more than a decade ago we still have no clear picture of the physical nature of the lenses. To…

Astrophysics · Physics 2007-05-23 Mark A. Walker

We present the detection of 107 pulsars with interstellar scintillation arcs at 856--1712\,MHz, observed with the MeerKAT Thousand Pulsar Array Programme. Scintillation arcs appear to be ubiquitous in clean, high S/N observations, their…

High Energy Astrophysical Phenomena · Physics 2022-11-17 R. A. Main , A. Parthasarathy , S. Johnston , A. Karastergiou , A. Basu , A. D. Cameron , M. J. Keith , L. S. Oswald , B. Posselt , D. J. Reardon , X. Song , P. Weltevrede

The central galaxies of some clusters can be strong emitters in the Ly$\alpha$ and H$\alpha$ lines. This emission may arise either from the cool/warm gas located in the cool core of the cluster or from the bright AGN within the central…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-13 S. Khedekar , E. Churazov , S. Sazonov , R. Sunyaev , E. Emsellem

We show the results of our analysis of the pulse broadening phenomenon in 25 pulsars at several frequencies using the data gathered with GMRT and Effelsberg radiotelescopes. Twenty two of these pulsars were not studied in that regard before…

High Energy Astrophysical Phenomena · Physics 2015-06-16 Wojciech Lewandowski , Marta Dembska , Jaroslaw Kijak , Magdalena Kowalinska

Magnetic fields grown by instabilities driven by differential rotation are believed to be essential to accretion onto black holes. These instabilities saturate in a turbulent state; therefore, the spatial and temporal variability in the…

Instrumentation and Methods for Astrophysics · Physics 2022-12-07 Chunchong Ni , Avery E. Broderick , Roman Gold

We report the discovery and timing of two pulsars from a sample of four circularly polarized sources identified in radio continuum images taken as part of the Australian SKA Pathfinder (ASKAP) Variables and Slow Transients (VAST) survey.…

High Energy Astrophysical Phenomena · Physics 2026-03-17 Rahul Sengar , David L. Kaplan , Emil Lenc , Akash Anumarlapudi , Natasha Hurley-Walker , Ziteng Wang , Laura Driessen , Dougal Dobie , Tara Murphy

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…

High Energy Astrophysical Phenomena · Physics 2019-04-17 F. Kirsten , N. D. R. Bhat , B. W. Meyers , J. -P. Macquart , S. E. Tremblay , S. M. Ord

We analyze a sample of 58 multi-wavelength, Very Long Baseline Array observations of active galactic nuclei (AGN) to determine their scattering properties. Approximately 75% of the sample consists of AGN that exhibit centimeter-wavelength…

Extreme scattering events (ESEs) in the interstellar medium (ISM) were first observed in regular flux measurements of compact extragalactic sources. They are characterized by a flux variation over a period of weeks, suggesting the passage…

We show that surface waves along interstellar current sheets closely aligned with the line of sight lead to pulsar scintillation properties consistent with those observed. This mechanism naturally produces the length and density scales of…

Astrophysics of Galaxies · Physics 2015-06-15 Ue-Li Pen , Yuri Levin

We report wideband scatter-broadening estimates of 14 pulsars towards the Gum nebula region using the Band-3 of the upgraded GMRT. This work increases the measurements of frequency scaling index of scatter-broadening ($\alpha$) across the…

High Energy Astrophysical Phenomena · Physics 2026-02-04 M. A. Krishnakumar , Bhal Chandra Joshi , P. K. Manoharan

Temporal broadening is a commonly observed property of fast radio bursts (FRBs), associated with turbulent media which cause radiowave scattering. Similarly to dispersion, scattering is an important probe of the media along the line of…

The pulse widths, dispersion measures and dispersion indices of Fast Radio Bursts (FRB) impose coupled constraints that all models must satisfy. We show that if the dispersion measures resulted from propagation through the intergalactic…

High Energy Astrophysical Phenomena · Physics 2015-01-07 J. I. Katz

We report on a recent global VLBI experiment in which we study the scatter broadening of pulsars in the spatial and time domain simultaneously. Depending on the distribution of scattering screen(s), geometry predicts that the less spatially…

Instrumentation and Methods for Astrophysics · Physics 2013-08-20 Olaf Wucknitz

We have measured 21-cm absorption and emission spectra in the direction of a further 7 southern pulsars with the Parkes telescope to derive their kinematic distances and to study the interstellar medium. For the first time we have…

Astrophysics · Physics 2009-10-31 Simon Johnston , B. Koribalski , J. M. Weisberg , W. Wilson

We report results of one of the most sensitive pulsar surveys to date targeting the innermost region of the Galactic Center (GC) using the Robert C. Byrd Green Bank Telescope (GBT) at X-band (8--12GHz) using data from the Breakthrough…

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