Host: Dong Lai
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Abstract:
The static-looking apparent night sky is, in reality, full of phenomena that are dynamic in nature and are often transient. One such category of transients is the stellar demises, also known as supernovae (SNe). Type II-P supernovae (SNe) were canonically established with a typical 100 day plateau in their temporal flux evolution, which is still a kind of ‘magic number’ for most of these SNe observed in nature. However, time and again, theoretical works have shown a great diversity in plateau lengths ranging from tens of days to more than 150 d. Longer plateau SNe have been studied in several works, yet, the short-plateau SNe were missing from the observational scenario. With the advent of surveys such as ZTF, ATLAS, etc., we are able to discover more diverse transients including Type II SNe with shorter plateaus. This talk is focused on short-plateau SNe with plateau lengths varying from 65 d to 75 d. We constrain various observational and physical properties associated with these events using ground and space-based multiwavelength observations. We further modeled these events by performing 1D hydrodynamical simulations to ascertain their explosion parameters and progenitor properties. The progenitors of short-plateau events were earlier thought to be high-mass red supergiant stars, going through an evolutionary process with standard mass loss prescription. Our findings revealed a large diversity in the progenitors of these events, indicating that the short-plateau events can come from a wide range of red supergiant stars with elevated mass loss. Furthermore, detailed spectroscopic follow up of these events in various phases are crucial for their understanding. We are discovering tens of thousands of such events yearly, yet, only a tiny fraction of these transients, specifically SNe, get much attention, a majority are left unclassified. In JWST era, with transient astronomy now reaching much higher redshifts, and the upcoming launch of the Vera C. Rubin Observatory, this number will explode. We will require more 4-10 m class telescopes to be able to follow up on these exciting transients.
Biography:
I am Rishabh Singh Teja and I will be joining TDLI as a postdoctoral fellow. This year I have obtained my PhD from the Indian Institute of Astrophysics, India with my thesis focused on short-plateau Type II supernovae. I have worked extensively in the multi-wavelength observations of core-collapse supernovae and their 1-D hydrodynamical modeling. I had finished my BSc (Hons) and MSc in Physics from the University of Delhi with the university Gold medal in the latter. I wish to further explore the time domain astronomy with multiwavelength observations of other exotic transients.
