by Dr. Viswesh Marthi, NCRA Pune

Abstract:

Stars twinkle due to atmospheric turbulence, as a result of
which their brightness as well as colour appear rapidly modulated. Planets
like Venus and Jupiter do not twinkle. At radio wavelengths, pulsars and
fast radio bursts (FRBs) offer the perfect analogy: they scintillate.
Scintillation carries the spectral imprint of the radio wave propagation
through the medium. Since radio astronomy operates in the regime of
coherent detection, the phase of the electric field carries vital
information about interstellar medium. Usually, it is difficult to
retrieve these phases, and it falls under the class of problems called
holography. However, the optical uses of scintillation are now beginning
to be explored using new algorithms and techniques, including very long
baseline interferometry, revealing the structure of the ionised
interstellar medium (IISM) at scales of 0.01 AU. Potentially, these
structures can themselves be used as an interferometer in the IISM to
achieve very high angular resolution at the pulsar or FRB. This talk will
be at a student-friendly level, where I'll convey the sense of excitement
of applying scintillation to the study of compact objects and the IISM.