X-Ray Properties of Narrow Line Seyfert 1 Galaxies

Anju, A. (2018) X-Ray Properties of Narrow Line Seyfert 1 Galaxies. Masters thesis, Indian Institute of Science Education and Research Kolkata.

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Abstract

The Fermi gamma-ray space telescope launched in the year 2008 has detected gamma ray emission in about half-a-dozen Narrow Line Seyfert 1 (NLSy1) galaxies, a class of active galactic nuclei (AGN). This has led to the unambiguous presence of relativistic jets in these sources. This discovery has also led to the identification of NLSy1 galaxies as a new population of extragalactic gamma ray emitting sources in addition to blazars and radio galaxies. This discovery of gamma ray emission in a minority of NLSy1 galaxies has thrown open many questions on the nature of the population of NLSy1 galaxies. In this project, we aim to understand the X-ray properties of a large sample of NLSy1 galaxies to (i) understand their general X-ray properties and (ii) to compare how the X-ray properties of NLSy1 galaxies compare to the blazar class of AGN, a dominant population of extragalactic gamma-ray emitting AGN. To achieve the above objectives, analysis of the spectral and timing properties of a large sample of NLSy1 galaxies was carried out. The data towards this project was taken from both XMM-Newton and NuSTAR. In this report we present results on our analysis of one NLSy1 galaxy PMN J0948+0022 using NuSTAR observation and 21 NLSy1 galaxies using XMM-Newton observations. From XMM-Newton observations, the sources are found to show X-ray flux variations with an average variability amplitude of 0.16⁺⁰.⁰²-₀.₀₂. The spectra were fitted with a simple power law with a photon index 2.41⁺⁰.⁰²-₀.₀₂. The flux variability nature as well as the spectral properties of these source are similar to what is known for blazars.

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