BGS/Student Seminars

A Study of Extragalactic NovaeComprehensive Seminar

by Shatakshi Chamoli (IIA-PU)

Asia/Kolkata
Auditorium

Auditorium

Description
Novae are a class of cataclysmic variables with an accreting White Dwarf (WD) primary and Roche Lobe filling secondary star. These systems go into outbursts as a consequence of thermonuclear runaway on the surface of the WD. It leads to an increase in the brightness of the system and the appearance of a "new star" in the sky. Observations of novae in the Milky Way are biased due to our location and dust obscuration towards the centre. Hence, we look to our neighbouring galaxies to study novae in different galactic components, like the spiral arms, bulge and halo. M31 (Andromeda) is visible for most of the year, suffers low extinction and has a higher nova rate than the Milky Way, making it an excellent site for novae population studies. We have conducted a multiwavelength survey of novae in M31 using the GROWTH-India Telescope (GIT) and the UltraViolet Imaging Telescope (UVIT). We have been observing the entire M31 at a daily cadence in multiple bands since 2022, supplemented by UVIT observations of the central field in the F148W filter. We have detected over 50% of the novae reported during the survey and performed detailed light curve analysis for these objects. We also observed the 2024 outburst of the recurrent Nova M31N 2017-01e, the second fastest nova with a recurrence period of 2.5 years. The position of this nova coincides with a blue variable counterpart showing a period of 14.3 days, which is unique for a nova of its kind. In this presentation, I will share preliminary results from our survey of M31 and the peculiar characteristics of M31N 2017-01e.
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