Abstract Details
| Name: Jigisha Affiliation: Raman Research Institute Conference ID: ASI2018_1745 Title : The dynamic spectral signatures from Lunar Occulation: A simulation study Authors and Co-Authors : Jigisha V. Patel and Avinash A. Deshpande Abstract Type : Poster Abstract Category : Instrumentation and Techniques Abstract : Lunar occultation, which occurs when moon crosses sight-lines to distant sources, has been studied extensively through apparent intensity pattern resulting from Fresnel diffraction, which depends on the angular size of the source, the frequency of observation and distance to the obstruction. Such Lunar occultation observations have been successfully used to measure angular sizes of extragalactic sources. However, such observations to-date have been mainly over narrow bandwidth, or averaged over the observing band, and the associated intensity pattern in time has never been examined in detail as a function of frequency over a wide range. 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 FRBs, which remain a mystery even after a decade of their discovery. In this presentation, we describe details of this investigation, relevant to radio frequencies at which FRBs have been detected, and discuss the findings, along with their implications. |