Related papers: Optical Variability of Narrow-Line Seyfert 1 Galax…
We present a 35 day ASCA observation of the NLS1 Akn 564, which was part of a multiwavelength AGN Watch monitoring campaign. Akn 564 shows a photon index varying across the range 2.45--2.72. The presence of the soft hump component below 1…
Narrow-line Seyfert 1 galaxies (NLS1s), a subclass of active galactic nuclei (AGNs) at early stage of accretion process, are also found to host relativistic jets. However, currently known jetted NLS1s are rare. The majority of NLS1s are…
The origin of radio emission in the majority of Active Galactic Nuclei (AGN) is still poorly understood. Various competing mechanisms are likely involved in the production of radio emission and precise diagnostic tools are needed to…
This article focuses on certain variability and emission characteristics of Active Galactic Nuclei (AGN), especially their radio-loud subset consisting of quasars, BL Lacs and $\gamma$-ray detected narrow-line Seyfert 1 galaxies, all of…
Narrow-line Seyfert 1 galaxies (NLS1s) are a class of active galactic nuclei (AGN) which are known to be one of the few sources of $\gamma$ rays, which originate in a relativistic beamed jet. Becuase of their relatively large distance, a…
The high quality light curves of Kepler space telescope make it possible to analyze the optical variability of AGNs with an unprecedented time resolution. Studying the asymmetry in variations could give independent constraints on the…
We present a detailed multi-frequency analysis of an intense monitoring programme of Seyfert 1 galaxy NGC 4593 over a duration of nearly for a month with Swift observatory. We used 185 pointings to study the variability in six…
In recent years, several Radio-Loud Narrow-Line Seyfert 1 galaxies (RL-NLS1) possessing relativistic jets have come into attention with their detections in Very Large Baseline Array (VLBA) and in $\gamma$-ray observations. In this paper we…
We present an overview on how variability can be used to constrain the location of the ionized outflow in nearby Active Galactic Nuclei using high-resolution X-ray spectroscopy. Without these constraints on the location of the outflow, the…
We have observed four low-luminosity active galactic nuclei classified as Type 1 LINERs with the X-ray Telescope (XRT) and the UltraViolet-Optical Telescope (UVOT) onboard Swift, in an attempt to clarify the main powering mechanism of this…
We report a detailed analysis of the XMM-Newton spectra of six Narrow-Line Seyfert 1 (NLS1) galaxies at redshift z = 0.35--0.92. Compared with the NLS1s at lower redshift in the previously most-studied sample, these NLS1s have larger black…
We report on a short optical monitoring programme of the narrow-line Seyfert 1 Galaxy IRAS 13224-3809. Previous X-ray observations of this object have shown persistent giant variability. The degree of variability at other wavelengths may…
The term 'active galactic nuclei' (AGN) subtends a huge variety of objects, classified on their properties at different wavelengths. Peaked sources (PS) represent a class of AGN at the first stage of evolution, characterised by a peaked…
Several narrow-line Seyfert 1 galaxies (NLS1s) have now been detected in gamma rays, providing firm evidence that at least some of this class of active galactic nuclei (AGN) produce relativistic jets. The presence of jets in NLS1s is…
Hundreds of Type 2 quasars have been identified in Sloan Digital Sky Survey (SDSS) data, and there is substantial evidence that they are generally galaxies with highly obscured central engines, in accord with unified models for active…
We studied the six gamma-ray-detected Narrow Line Seyfert 1 (NLSy1) galaxies using the hard X-ray observations from Nuclear Spectroscopic Telescope Array (NuSTAR) and optical g- \& r-band from Zwicky Transient Facility (ZTF). The X-ray…
Low Luminosity Active Galactic Nuclei (LLAGNs) are contaminated by the light of their host galaxies, thus they cannot be detected by the usual colour techniques. For this reason their evolution in cosmic time is poorly known. Variability is…
We present a detailed timing and spectral study of an extremely variable narrow-line Seyfert~1 galaxy NGC 4748 using observations in the year 2017 and 2014 performed with AstroSat and XMM-Newton, respectively. Both observations show…
We present the results of an intensive ultraviolet monitoring campaign on the Seyfert 1 galaxy NGC 4151, as part of an effort to study its short time-scale variability over a broad range in wavelength. The nucleus of NGC 4151 was observed…
Narrow-line Seyfert 1 galaxies (NLS1s) are active galactic nuclei (AGN) recently identified as a new class of $\gamma$-ray sources. The high energy emission is explained by the presence of a relativistic jet observed at small angles, just…