Monday, December 24 2018
15:30 - 17:00

Alladi Ramakrishnan Hall

Narrow line Seyfert 1 galaxies: A new class of gamma-ray emitting AGN

C.S. Stalin

Indian Institute of Astrophysics

he extragalactic gamma-ray sky as seen by the Fermi gamma-ray space telescope is dominated by the blazar class of active galactic nuclei (AGN). In addition to blazars Fermi has discovered for the first time gamma-ray emission in a minority of Narrow Line Seyfert 1 (NLSy1) galaxies identified as a separate class of AGN by Osterbrock and his group about three decades ago. This discovery of gamma-ray emission in NLSy1 galaxies by Fermi clearly points to the presence of relativistic jets in
them and has brought to question the nature of NLSy1 galaxies. We have carried out detailed multi-wavelength studies on these new class of gamma-ray emitting NLSy1 galaxies. Our analysis indicates that these sources are the low black hole mass counterparts to the flat spectrum category of AGN. In addition to the results on NLSy1 galaxies, I will also highlight some recent observations from the ultra-violet imaging telescope on-board India's multi-wavelength astronomical Observatory, AstroSat launched by the Indian Space Research Organization in 2015.

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