Related papers: Coronal Line Emission from NLS1s
We study 12 Seyfert 1 galaxies with a high level of optical polarization. Optical light emerging from the innermost regions is predominantly scattered in a polar region above the central engine directly in our line of sight. These sources…
We investigate the origin of the soft X-ray excess emission from narrow-line Seyfert 1 galaxies Akn564 and Mrk1044 using XMM-Newton observations. We find clear evidence for time delays between the soft and hard X-ray emission from Akn564…
I provide a short review of the properties of Narrow-line Seyfert 1 (NLS1) galaxies across the electromagnetic spectrum and of the models to explain them. Their continuum and emission-line properties manifest one extreme form of Seyfert…
We present here an analysis of the X-ray properties of a sample of LINER galaxies observed with the ROSAT PSPC and HRI instruments. A spatial analysis shows that the bulk of the X-ray emission is consistent with arising from a point source;…
The intensity of the soft X-Ray background is correlated with the distribution of galaxies. To demonstrate this, magnitude limited galaxy samples extracted from bright galaxy catalogues and the Lick counts are utilized. Significant…
Although the properties of the narrow-line region (NLR) of active galactic nuclei(AGN) have been deeply studied by many authors in the past three decades, many questions are still open. The main goal of this work is to explore the NLR of…
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…
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…
The study of NLS1s using ASCA has many advantages. A representative sample can be studied; to date, observations of more than 30 NLS1s have been made. ASCA observations are conducted contiguously, so their X-ray variability properties can…
The current status of understanding of the X-ray emission from Seyfert galaxies involves Comptonization of soft photons by hot subrelativistic electrons. After briefly reviewing the early theoretical basis for the presence of hot optically…
Complex narrow line Seyfert 1s (NLS1s), such as 1H0707-495, differ from simple NLS1s like PG1244+026 by showing stronger broad spectral features at Fe K and larger amplitude flux variability. These are correlated: the strongest Fe K…
We study X-ray and UV emission from the narrow-line Seyfert 1 galaxy II~Zw~177 using a $137\ks$ long and another $13\ks$ short \xmm{} observation performed in 2012 and 2001, respectively. Both observations show soft X-ray excess emission…
We revisited the spectroscopic characteristics of narrow-line Seyfert 1 galaxies (NLS1s) by analysing a homogeneous sample of 296 NLS1s at redshift between 0.028 and 0.345, extracted from the Sloan Digital Sky Survey (SDSS-DR7) public…
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…
We report the results of near infrared observations of 19 soft X-ray selected AGN. The goal of the observations was to search for strong, narrow Paschen-alpha or Brackett-gamma emission lines, as a sign of nuclear starbursts. We found…
This paper presents a comprehensive study of the X-ray properties of low-ionization nuclear emission-line regions (LINERs) and low-luminosity Seyfert galaxies based on observations obtained with ASCA. We analyzed data of 53 observations of…
We present optical spectra and emission-line ratios of 12 Narrow-Line Seyfert 1 (NLS1) galaxies that we observed to study the ionizing EUV continuum. A common feature in the EUV continuum of active galactic nuclei is the big blue bump…
(abridged) With the commissioning of XMM came the discovery of 2.5-10 keV spectral complexity in some narrow-line Seyfert 1 galaxies (NLS1). In this work, we define two samples of NLS1: a complex sample whose members exhibit high-energy…
Coronal lines are forbidden emission lines with a ionisation potential $\chi\gtrsim100\,{\rm eV}$. They are linked to energetic phenomena triggered by AGNs in the circumnuclear medium. We present the first high-angular-resolution…
We study a sample of Narrow-line Seyfert 1 galaxies (NLS1) in their optical and radio features, in order to understand the differences between their radio silent, radio-loud and radio-quiet subclasses. We first show that the different…