Archive abstract

Abstract of the proposal for the experiment EM140A


The tidal disruption of a star by a dormant supermassive black hole at galactic centers results in an accretion powered thermal flare in optical/UV bands. The accretion can power a relativistic jet, which upon interaction with the surrounding circum-nuclear medium produces non-thermal radio emission. The transient AT2019dsg (z = 0.051) was discovered on 4 April 2019 by the Zwicky Transient Factory and classified as a potential tidal disruption event based on the broad He lines , a blue continuum emission and a spatial coincidence with the host galaxy center. Based on a preliminary modeling, the synchrotron self-absorption peak is expected at ~ 1 - 2 GHz upto 180 days from the reported flare; the flux density at higher observation frequencies either increases with time or remains stable at the mJy level. Staggered C-band EVN observations will help resolve the compact source structure, enable a measurement of proper motion and a monitoring of flux density and size evolution which in conjunction with physical models can address the energetics and environmental properties of the source. The relative proximity of the source, location in the northern sky and current rising phase make it ideally suited for observations with the EVN.
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