I have been involved in outreach-related activities related to astronomy. I was event Chair for the
; a conference which brought together about 160 Ph.D students working in astronomy across the country. In 2021, we founded a web portal named Young Astronomers' Meet (YAM)-2022 , a platform to present simplified versions of research articles in astrophysics to the general public. I was responsible for managing the website until October 2022, and edit articles received from researchers across the country regularly. Besides, I have actively participated in various outreach activities at my institute, some of which include the ARIES CosmicVarta , held on the 28th of February 2021, and the National Science Day celebration , which took place during the COVID-19 lockdown in the months of May and June 2020.
ARIES e-lecture series
I am a part of a group which studies the properties of the most luminous objects in the known universe yet:
Active Galactic Nuclei (AGN). We use various techniques backed by observational data in X-ray, UV, Optical and radio wavelengths to understand the behaviour of matter in the close proximate regions of the Supermassive Black Holes residing at the centre of these objects. See this video for a very helpful animation zooming into the inner regions of quasars. My Ph.D thesis aims to resolve the inner (sub-parsec) regions of these objects through multi-band observations and inferring the structure and kinematics of matter in those locations.
Resolving the accretion disk structure in AGN: As the innermost regions of AGN are too difficult to resolve spatially, a technique known as *Reverberation Mapping* is used to resolve these innermost regions. As the light travels from the inner to our regions, the fluctuations in the two regions can be recorded, with a lag understood as the light travel time. This technique yields the size of the accretion disk.
Understanding the dynamics of gas in the broad line region (BLR) of AGN: We don't know what is the structure and the dynamics of gas in the BLR. To understand the dynamics of matter in these regions, we use emission line diagnostics as a tool. The various emission lines (Hα, Hβ, MgII, CIV etc. ) originating from these regions can be resolved using ground-based spectroscopic measurements, which provide clues to the structure and dynamics of matter in these regions.
Microvariability studies for a handful of interesting AGN: AGN are known to be variable at all time scales. We exploit this method to relate the exciting phenomenon observed in different wavelengths such as weak emission lines, radio jets and the γ- ray emission, with the microvariability observed in these AGNs.
Photometric Reverberation Mapping: we use the technique of Photometric reverberation mapping using narrow band filters to extract the size and extent of the BLR in AGNs. This method is quite efficient at getting the sizes with a fraction of the telescope time needed for the traditional reverberation mapping campaigns.
Changing look Active Galaxies: Discovery of changing look active galaxies has recently challenged the unified model of active galaxies, however, the possible underlying physical mechanism responsible for the changing-look phenomena is still unclear. We use multi-band polarimetric observations of these changing look AGNs (CLAGN) with the aim of constraining the polarization state and angle of these CLAGNs, which allows us to understand the AGN host galaxies with respect to the general population of galaxies.
Physical properties of very high redshift (z> 5) quasars:
High redshift quasars, being the most luminous non-transient objects, hold the keys to the understanding of the universe during and immediately after the epoch of cosmic re-ionization Using a subset of IR bright quasars, we look for the quasar properties including the SMBH mass using the CIV and MgII emission lines arising out of the Broad-line region of these quasars.
Some of the interesting results obtained recently have been published in papers listed below. Please have a look at them:
In this work, we have studied the Hβ emission line profiles in a peculiar class of Seyfert galaxies: the Narrow Line Seyferts. Using a combination of 11 physical parameters, we have studied the behaviour of a sample of around 150 NLSy1 galaxies as compared to the general Broad Line Seyfert population and discovered that peculiar behaviour of NLSy1 galaxies holds true for a large sample.
AGN are known to be variable at all time scales. In this project, we use a handful of peculiar Narrow Line Seyfert 1 (NLSy1) Galaxies, and checked for the variability at smallest time scales. We relate the phenomenon of γ ray emission jet with the microvariability observed in this sample of AGN and find out that these AGNs behave like blazars at shorter time scales of variability.
As the innermost regions of AGN are too difficult to resolve spatially, we use a technique known as Reverberation Mapping to resolve these innermost regions. As the light travels from the inner to our regions, the fluctuations in the two regions can be recorded, with a lag which is understood as the light travel time. This technique yields the size of the accretion disk. In this work we have used this technique to measure the accretion dize sizes for 19 AGNs selected from the ZTF survey.
Photometric Reverberation mapping is a cost-effective alternative to traditional reverberation mapping. However, the technique has not been used for a large sample of quasars so far. In this work, we have calibrated the technique of PRM with the traditional RM and also performed simulations to devise an optimum strategy for a successful PRM campaign.
. In this study, we present initial results from our accretion disk reverberation mapping campaign targeting AGN with Super High Eddington
Accreting Black Holes (SEAMBH). Our analysis on one of the sources- IRAS 04416+1215;
based on the broadband observations using the Growth India telescope (GIT), reveals that the
size of the accretion disk for this source, calculated by cross-correlating the continuum light
curves is larger than expected from the theoretical model.
Born with an innate desire to travel around the world, I consider myself lucky to be in a profession where I can travel a lot both for work and fun.
At the moment, my travel diary is filled with a few places in India coupled with a visit to China but with time I aim to travel to all the 7 continents on the planet. Some recent travel blog posts are posted below.
I traveled to Kerala in October 2018 only to be left mesmerized by the beauty, culture and the cleanliness of the part of my country rightly known as the 'God's own country'. This article is my version of the experience I had in approximately a week that I spent in Kerala.
China as a place, has always fascinated me since childhood! This article is about my maiden trip to China, which resulted due to an international conference held in Guilin, Guanxi province.
Not too many people have Nagaland in their bucket list. Uncomfortable roads, poor transport system and a lot of corruption are a few factors which contribute to it. Added to it the stories of a still very active insurgency, Nagaland although an extremely beautiful hill state doesn't manage to attract a lot of tourists.
I traveled to Nagaland and of course, will definitely want to visit again!
Sometimes few random things cross my mind and get structured in the form of sometimes little, sometimes eerily long blog posts. Currently, my blog is live on medium. A few posts are avilable below.
Two books by Sanjeev Sanyal, a noted economist: 'Ocean of Churn' and 'The land of the seven rivers' offer a very different perspective on the history of ancient India, in a manner untold before. Both of the books offer a very interesting journey through the geography of India and its surrounding lands and the ocean. I present a brief review of both the book simultaneously.
A personal account of the lockdown implemented to counter spread of the ongoing COVID-19 disease.
The radio has seen a rapid change thanks to the internet broadcast. With 100,000+ channels available to listen for free, is it a watershed moment for the world of radio entertainment? In this article, I put my thoughts regarding the resurgence of radio in the internet era and how to enthrall ourselves with the exciting world of radio.