MSV-2035 Astronomy Document - Inside Design - FINAL - FINAL

Astronomy & Astrophysics 52 complexities in the physical conditions of the various components of these systems. Based on long term spectroscopic monitoring during quiescence, the presence of a white dwarf primary was firmly established in recurrent novae with giant secondaries. Using observations during outburst, it was shown that the mass of the white dwarf in the recurrent nova U Sco is increasing. The first detection of low frequency synchrotron radio emission from a recurrent nova was made by the GMRT observations of the 2006 outburst of the recurrent nova RS Oph. AstroSat's SXT and UVIT are carrying out unprecedented high cadence observations of novae, catching the emergence of supersoft phase of a nova and its highly variable and poorly understood evolution on very rapid scales of minutes to hours. Observations of the recurrent nova V3890 Sgr using the AstroSat during its supersoft X-ray phase following the 2019 outburst provided the densest possible monitoring of a nova outburst from a low-Earth orbit. It demonstrated the fast evolution of the super-soft emission in this object, including a rapid first appearance on day 8.57 after the outburst, clearly establishing the presence of a massive white dwarf primary in the system.All these results are of immense importance in the studies of nova systems as potential single degenerate progenitors of supernovae of Type Ia. The use of SNe Ia as cosmological probes requires an understanding of the homogeneity and heterogeneity of these system through detailed studies of the events occurring at low redshifts. This has been the main theme in the studies of SNe Ia that have led to a few important results. Early phase spectra of several events have shown the presence of carbon rich dust in their ejecta, indicating differences in the explosion channel. The studies of low luminosity Iax events have shown these supernovae to be the result of a pure deflagration explosion, most likely in a double degenerate system. Detailed analysis of the light curve of the nearby, normal Ia, SN 2014J, indicated the properties of the interstellar medium in its host galaxy to be different from that of theMilkyWay. Various types of core collapse SNe (CCSNe) have been studied extensively. Starting with a detailed spectroscopic monitoring of the nearby H-rich supernova SN 1987A (from VBO) that led to the identification of barium in the hydrogen-rich CCSNe, several CCSNe have been studied to understand dust formation, circumstellar material (CSM) interaction and for constraining the underlying physical mechanisms. While the very early phase observations in the optical have enabled the detection of shock breakout (e.g. in SN 2018hna) and indications of CSM interaction (e.g. SN 2016gfy, SN 2019uo), the late time radio observations of several CCSNe (e.g. SN 1993J, SN 2004dj, SN 2010jl) have enabled constraining the physical parameters of the CSM. Atargeted survey of 24 recent CCSNe in the low frequency radio using the GMRT led to the detection of just about 6 events. Based on polarimetric observations, and observations during the late phases, presence of dust and asymmetry in the ejecta have been inferred for many supernovae. Such studies provide important constraints on the mass loss in the progenitor during its evolution. Long termmonitoring of the stripped envelope Type Ib SN 2001em using the GMRT indicated interaction between the supernova ejecta and the dense shell indicative of a massive binary system as possible progenitor. Comparing theoretical simulations of light curves and synthetic spectra with observations, explosion parameters and progenitor properties of several supernovae Multi-wavelength observations of various types of SNe has been an active programme for the researchers in the country. The observations, made primarily using Indian facilities but also quite often combined with data from international facilities, typically range from pre-maximum to late post-maximum days. The major goals of these studies are to estimate the explosion parameters constraining underlying physical mechanisms, understand the host galaxy properties and interaction of the supernova with its immediate environment, in an attempt to understand the progenitors and explosionmechanisms of various types of supernovae. MEGA SCIENCE VISION-2035