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We present the results of flux density monitoring of PSR B0329+54 at the frequency of 4.8 GHz using the 32-meter TCfA radiotelescope. The observations were conducted between 2002 and 2005. The main goal of the project was to find…

Astrophysics of Galaxies · Physics 2015-05-28 Wojciech Lewandowski , Jaroslaw Kijak , Yashwant Gupta , Krzysztof Krzeszowski

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

The initial pulse complex (IPC) in short gamma-ray bursts is sometimes accompanied by a softer, low-intensity extended emission (EE) component. In cases where such a component is not observed, it is not clear if it is present but below the…

High Energy Astrophysical Phenomena · Physics 2010-06-25 Jay P. Norris , Neil Gehrels , Jeffrey D. Scargle

We derive the distribution of flux density of a compact source exhibiting strong diffractive scintillation. Our treatment accounts for arbitrary spectral averaging, spatially-extended source emission, and the possibility of intrinsic…

Instrumentation and Methods for Astrophysics · Physics 2012-08-09 Michael D. Johnson , Carl R. Gwinn

We have made observations of 98 low-Galactic-latitude pulsars to measure pulse broadening caused by multipath propagation through the interstellar medium. Data were collected with the 305-m Arecibo telescope at four radio frequencies…

Episodic accretion plays an important role in the evolution of young stars. Although it has been under investigation for a long time, the origin of such episodic accretion events is not yet understood. We investigate the dust and gas…

Solar and Stellar Astrophysics · Physics 2019-10-16 Andreas Postel , Marc Audard , Eduard Vorobyov , Odysseas Dionatos , Christian Rab , Manuel Güdel

We propose that interstellar extreme scattering events, usually observed as pulsar scintillations, may be caused by a coherent agent rather than the usually assumed turbulence of $\rm H_2$ clouds. We find that the penetration of a flux of…

Astrophysics of Galaxies · Physics 2013-12-03 M. Angeles Perez-Garcia , Joseph Silk , Ue-Li Pen

Temporal scatter-broadening can seriously affect our ability to find pulsars orbiting the central mass in our Galaxy. Many of these invaluable probes of geometry around the black hole are expected, but none have been found in close orbits…

Astrophysics of Galaxies · Physics 2015-01-20 Olaf Wucknitz

We present Karl G. Jansky Very Large Array radio observations of the long gamma-ray burst GRB 161219B ($z=0.147$) spanning $1-37$ GHz. The data exhibit unusual behavior, including sharp spectral peaks and minutes-timescale large-amplitude…

We report the discovery of complex flaring activity from the galactic nucleus hosting the five-year-old tidal disruption event eRASSt J234402.9-352640 (J2344). With Einstein Probe and XMM-Newton observations, we detected highly structured…

We present study of a typical explosive event (EE) at sub-arcsecond scale witnessed by strong non-Gaussian profiles with blue- and red-shifted emission of up to 150 km/s seen in the transition-region Si IV 1402.8 \AA, and the chromospheric…

Solar and Stellar Astrophysics · Physics 2015-06-23 Zhenghua Huang , Maria S. Madjarska , Lidong Xia , J. G. Doyle , Klaus Galsgaard , Hui Fu

We present two years of monitoring observations of the extremely variable quasar J1819+3845. We observe large yearly changes in the timescale of the variations (from ~ 1 hour to ~ 10 hours at 5GHz). This annual effect can only be explained…

Astrophysics · Physics 2009-11-07 J. Dennett-Thorpe , A. G. de Bruyn

Extremely asymmetrical scattering (EAS) is a highly resonant type of Bragg scattering with a strong resonant increase of the scattered wave amplitude inside and outside the grating. EAS is realized when the scattered wave propagates…

Optics · Physics 2015-06-26 Timo A. Nieminen , Dmitri K. Gramotnev

The dynamic and secondary spectra of many pulsars show evidence for long-lived, aligned images of the pulsar that are stationary on a thin scattering sheet. One explanation for this phenomenon considers the effects of wave crests along…

Astrophysics of Galaxies · Physics 2018-05-16 Dana Simard , Ue-Li Pen

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…

Extended gamma-ray emission, interpreted as halos formed by the inverse-Compton scattering of ambient photons by electron-positron pairs, is observed toward a number of middle-aged pulsars. The physical origin and actual commonness of the…

High Energy Astrophysical Phenomena · Physics 2022-09-21 Pierrick Martin , Alexandre Marcowith , Luigi Tibaldo

We present long-term observations of two intermittent pulsars, PSRs~J1832+0029 and J1841$-$0500 using the Parkes 64\,m radio telescope. The radio emission for these pulsars switches "off" for year-long durations. Our new observations have…

High Energy Astrophysical Phenomena · Physics 2020-07-08 S. Q. Wang , J. B. Wang , G. Hobbs , S. B. Zhang , R. M. Shannon , S. Dai , R. Hollow , M. Kerr , V. Ravi , N. Wang , L. Zhang

We present average flux density measurements of 151 radio pulsars at 1.4 GHz with the Parkes 'Murriyang' radio telescope. We recommend our results be included in the next version of the ATNF pulsar catalogue. The large sample of pulsars…

High Energy Astrophysical Phenomena · Physics 2023-01-25 Ziyang Wang , Jingbo Wang , Na Wang , Shi Dai , Jintao Xie

We present timing solutions and analyses of 11 pulsars discovered by the Five-hundred-meter Aperture Spherical radio Telescope (FAST). These pulsars were discovered using an ultra-wide bandwidth receiver in drift-scan observations made…

We present the results from an Australian Square Kilometre Array Pathfinder search for radio variables on timescales of hours. We conducted an untargeted search over a 30 deg$^2$ field, with multiple 10-hour observations separated by days…