Avinash A. Deshpande
Articles written in Journal of Astrophysics and Astronomy
Volume 37 Issue 4 December 2016 Article ID 0037 Review
In the rapidly developing field of study of the transient sky,fast radio transients are perhaps the most exciting objects of scrutiny at present. The SKA, with its wide field-of-view and significant improvement in sensitivity over existing facilities, is expected to detect a plethora of fast transients which, in addition to help resolve the mysteries surrounding their nature and origin, will also lead to other interesting applications in astrophysics. We explore some of these possibilities here, and also emphasize the current status and future plans of the Indian communityworking in this area, in the context of ongoing work and extensionof this to the SKA.
Volume 38 Issue 3 September 2017 Article ID 0057
We report the results of our numerical simulation of classical-dissipative dynamics of a charged particle subjected to a non-Markovian stochastic forcing. We find that the system develops a steady-state orbital magnetic moment in the presence of a static magnetic field. Very significantly, the sign of the orbital magnetic moment turns out to be
Volume 40 Issue 1 February 2019 Article ID 0003
Lunar occultation, which occurs when the Moon crosses sight-lines to distant sources, has been studied extensively through apparent intensity pattern resulting from Fresnel diffraction, and has been successfully used to measure angular sizes of extragalactic sources. However, such observations till date havebeen mainly over narrow bandwidth, or averaged over the observing band, and the associated intensity pattern in time has rarely been examined in detail as a function of frequency over a wide band. Here, we revisit the phenomenon of lunar occultation with a view to study the associated intensity pattern as a function of both time and frequency. Through analytical and simulation approach, we examine the variation of intensity across the dynamic spectra, and look for chromatic signatures which could appear as discrete dispersed signal tracks, when the diffraction pattern is adequately smoothed by a finite source size. We particularly explore circumstances in which such diffraction pattern might closely follow the interstellar dispersion law followed by pulsars and transients, such as the Fast Radio Bursts (FRBs), which remain a mystery even after a decade of their discovery. In this paper, we describe details of this investigation, relevant to radio frequencies at which FRBs have been detected, and discuss our findings, along with their implications. We also show how a
Volume 40 | Issue 6
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