| Name: | Neeraj Kumari |
| Affiliation: | Physical Research Laboratory Ahmedabad |
| Conference ID : | ASI2024_614 |
| Title : | Multi-wavelength studies of Active Galactic Nuclei (AGNs) |
| Authors : | Neeraj Kumari, Sachindra Naik, Arghajit Jana, Main Pal |
| Authors Affiliation: | Neeraj Kumari, Sachindra Naik (Physical Research Laboratory, Ahmedabad 380009 India)
Arghajit Jana (Instituto de Estudios Astrofisicos, Universidad Diego Portales, Santiago, Chile)
Main Pal (Centre for Theoretical Physics, Jamia Millia Islamia, New Delhi-110025, India) |
| Mode of Presentation: | Oral |
| Abstract Category : | Thesis |
| Abstract : | Active Galactic Nuclei (AGNs) are the most luminous and persistent objects in the Universe, emitting in entire wavelength range from radio to Gamma rays. This enormous radiation is attributed to the accretion of material onto a supermassive black hole located at the centre of a galaxy. The SED of type1 AGN shows the presence of primary spectral components such as big blue bump in UV range, soft X-ray excess below ~2keV, Fe emission lines in 6-7keV, reflection hump in 10-50keV range and power-law continuum emission with high energy cut-off. These components are thought to be originating from distinct regions of AGN and are expected to vary differently. One of the most important properties of these objects is that they are highly variable on different time scales. Our understanding of variability properties of these objects is still not complete. Therefore, the spectral and timing studies of the AGNs can provide a better understanding of the central engine and its surrounding medium. This thesis work is dedicated to the analytical studies of three Seyfert galaxies: Mrk509, NGC1566 and NGC4051.
To fulfil the thesis objectives, the data from various space-based observatories such as Swift, XMM-Newton and NuSTAR are utilized. To disentangle the origin of short-term variabilities in Seyfert 1 galaxy Mrk509, long-term Swift data from 2006 to 2019 in multi-waveband have been used. Another detailed spectral and timing study has been performed for the 2018 outburst of the Changing-look AGN (CL-AGN) NGC1566 where its intensity increased up to ~25-30 times its quiescent state intensity. The CLAGNs are a newly emerging class of AGNs where an
AGN switches its type over the years. Lastly, a small flaring event in narrow-line Seyfert1 (NLS1) galaxy NGC4051 has been studied in detail. The methodology, results and inferences obtained from these studies will be discussed in the talk. |
