# Talks presented so far. This page is a collection of various talks I have presented at my home institute and/or national/international seminars, conferences or workshops. ## ARIES annual research scholars' review , Spetember 2020: <iframe src="https://docs.google.com/presentation/d/e/2PACX-1vQ-qiTH-GuNM2dPYTLgxU0TMVowVLPOzAAYxDNECj2Mh6jc4IMoYbcqEU8jUJKOD5HuHwNNNPC60f_N/embed?start=false&loop=false&delayms=3000" frameborder="0" width="660" height="469" allowfullscreen="true" mozallowfullscreen="true" webkitallowfullscreen="true"></iframe> ## BAO meeting, Armenia, Spetember 2020: <iframe src="https://docs.google.com/presentation/d/e/2PACX-1vSWcceTi26db7pEUUaDrUdNsnBNbzR9KxlRS1EXfLYADrlAS5DiSsa--HVMpGIroGRmFoU34dm3sA4f/embed?start=false&loop=false&delayms=3000" frameborder="0" width="660" height="469" allowfullscreen="true" mozallowfullscreen="true" webkitallowfullscreen="true"></iframe> ## ARIES online seminar series, April 2020: <iframe src="https://docs.google.com/presentation/d/e/2PACX-1vTfHDZON1V35fHTG9E-wVuTANOSL4dTETNityhot9Mkl3gct9PHfD3ngIt5HdtpGi-nDb1SwTr1kl4i/embed?start=false&loop=false&delayms=3000" frameborder="0" width="660" height="469" allowfullscreen="true" mozallowfullscreen="true" webkitallowfullscreen="true"></iframe> ## Poster presented in Guilin, China, September 2019. <iframe src="https://docs.google.com/presentation/d/e/2PACX-1vR0DfS1P2Mxm6IH7_4fWrYojErCLmUuf1CTxwE9Iw0fCmGMlf3kgIaC23o9ilNdFIVVhwE8YnqbQwVr/embed?start=false&loop=false&delayms=3000" frameborder="0" width="646" height="803" allowfullscreen="true" mozallowfullscreen="true" webkitallowfullscreen="true"></iframe> ## ARIES Pre-Ph.D. coursework talk-2, June 2019: <iframe src="https://docs.google.com/presentation/d/e/2PACX-1vQMm6_DrlWgBmQzyFcg0aQtRor9Ur6vyDwJkns5d1zWIPMClN-IBQH3Z4uyhIHovaq6ID9jl85h9oAG/embed?start=false&loop=false&delayms=3000" frameborder="0" width="660" height="469" allowfullscreen="true" mozallowfullscreen="true" webkitallowfullscreen="true"></iframe> ## ARIES Pre-Ph.D. coursework talk-1, April 2019: <iframe src="https://docs.google.com/presentation/d/e/2PACX-1vTzMrwKhkqxQ8R5WnipljmR6HAJdDmtDQwE5yGubvTFymkMEy8_xWsR9fSx2zIWPiJStCNCT1Xe5bSM/embed?start=false&loop=false&delayms=3000" frameborder="0" width="660" height="469" allowfullscreen="true" mozallowfullscreen="true" webkitallowfullscreen="true"></iframe>
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research
Posts reated to my research activities
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Research Section

:::info This page is a brief collection of all my present research activities. Here I put the results obtained from the various research projects, few talks/posters that I present related to those results and the resulting publications out of these projects. I will also attempt to write popular science level articles related to various aspects of my work. ::: This animation is an artistic impression of the inner regions of an active galaxy. The animation starts with the optical image of 3C273, a very well known quasar and zooms in up to the sub-parsec scale, where the clumps of gas known as the Broad Line Region (BLR) clouds exist embedded beneath a torus of dust. (video Courtesy: ESO YouTube channel) In early February 1963 Martin Schmidt at the California Institute of Technology, recognized that the spectrum of a radio detected source 3C 273 could be interpreted as if the source is located at red-shift 0.16. This was the first ever discovered quasar, short for quasi stellar source as it was initially known. Within a few years, a lot of such extra-galactic sources were discovered which since then are known as Active galactic Nuclei or AGN. The term quasar is now commonly used for AGN with high luminosity. Active galaxies differ from normal galaxies by the fact that they are luminous objects which outshine their own host galaxies and the high luminosity arises due to the actively accreting Super massive Black Hole (SMBH) residing at the centre. This activity provides us observational signature in all the energy bands. The accretion of matter can be described in the form of optically thick, geometrically thin accretion disk formed in the vicinity of the SMBH. Click here to know more.

7/25/2022
Some review papers which must be read by every beginner student in quasar astronomy.

This is a list of papers related to Active Galactic Nuclei. This list is not aimed to be comprehensive as new knowledge keeps getting on every few days. I'll keep updating this list time and again to keep this list current and meaningful. I am including the paper title and abstracts as well, to save some of my time and efforts. All the articles have links to the full articles available online. 1. The emission lines of quasars and similar objects Kris Davidson, Hagai Netzer (1979) link for full paper. Much of our information about quasars is derived from their emission-line spectra. The analysis of such spectra has become an intricate subject which differs considerably from traditional, low-density nebular astrophysics. This review is intended to explain our present understanding of the situation, including some aspects of galactic nuclei whose luminosities are more modest than quasars. Quasars line-emitting regions are probably photoionized (even if supplementary heating processes also occur). So far, models have been constructed which include ionization and thermal equilibria, the transfer of resonance-line and related photons, and the likely effects of absorption and scattering by dust grains. From comparisons between emission-line intensities produced in these models and observed quasars spectra, it appears that certain densities and pressures and size scales occur in or around quasars. The relative abundances of nitrogen, and oxygen in particular —are moderately "overabundant" elements are not very far from solar values, although it is suspected that heavy elements carbon, in quasars. The emission-line intensities also provide indirect information about quasars ultraviolet and soft-x-ray continua; there are hints that photons with energies between 20 and 300 eV which are not directly observable may even represent the peak of the luminous output of a typical quasar. Finally, some gas-dynamical questions, while extremely important, are very difficult to answer, because of a lack of observables. 2. An introduction to active galactic nuclei: Classification and unification

2/10/2021
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