Related papers: Narrow-Line Seyfert 1 Galaxies
It is known that the spectral energy distribution (SED) of the nuclear radiation of narrow-line Seyfert 1 galaxies (NLS1s) has different shapes with respect to that of ordinary broad-line Seyfert 1 galaxies (BLS1s), particularly in…
The study of narrow-line Seyfert 1 galaxies (NLS1s) is now mostly limited to low redshift ($z<0.8$) because their definition requires the presence of the H$\beta$ emission line, which is redshifted out of the spectral coverage of major…
We present the preliminary results of a survey performed with Swift to observe a sample of radio-loud Narrow-Line Seyfert 1 Galaxies (RLNLS1s). Optical-to-X-ray data from Swift are complemented with gamma-ray observations from Fermi/LAT and…
Narrow-line Seyfert 1 galaxies (NLS1s) exhibit extreme soft X-ray excess and large variability. We argue that both features can be basically accounted for by the slim disk model. We assume that a central black-hole mass in NLS1 is…
Narrow-line Seyfert 1 (NLS1) galaxies are peculiar active galactic nuclei (AGN). Most of them do not show strong radio emission, but recently seven radio-quiet (or -silent) NLS1s have been detected flaring multiple times at 37 GHz by the…
We study the properties of infrared-selected QSOs (IR QSOs), optically-selected QSOs (PG QSOs) and Narrow Line Seyfert 1 galaxies (NLS1s). We compare their properties from the infrared to the optical and examine various correlations among…
We present evidence that the outflowing UV absorbers in Seyfert 1 galaxies arise primarily in their inner narrow (emission) line regions (NLRs), based on similarities in their locations, kinematics, and physical conditions. 1) Hubble Space…
The recent detection of high-energy gamma rays from Narrow-Line Seyfert 1 Galaxies has confirmed that also this type of active galactic nuclei can generate powerful relativistic jets. I outline the evolution of the knowledge in this…
The detection of significant $\gamma$-ray emission from radio-loud narrow line Seyfert 1 (NLSy1s) galaxies enables us to study jets in environments different than those in blazars. However, due to the small number of known $\gamma$-ray…
The [O III] $\lambda\lambda$ 4959,5007 lines are a useful proxy to test the kinematic of the narrow-line region (NLR) in active galactic nuclei (AGN). In AGN, and particularly in narrow-line Seyfert 1 galaxies (NLS1s) these lines often show…
We present the detection of compact radio structures of fourteen radio-loud narrow line Seyfert 1 (NLS1) galaxies from Very Long Baseline Array observations at 5 GHz, which were performed in 2013. While 50\% of the sources of our sample…
We present a detailed study of 11 narrow-line Seyfert 1 galaxies (NLS1s) from the Six-degree Field Galaxy Survey (6dFGS) that both have optical and X-ray spectroscopic observations. There are five complex NLS1s (C-NLS1s) and six simple…
We argue that the narrow line regions of Seyfert galaxies are powered by the transport of energy and momentum by the radio-emitting jets and consequently that the ratio of the radio power to jet energy flux is much smaller than is usually…
We report the finding of kiloparsec (kpc)-scale radio structures in three radio-loud narrow-line Seyfert 1 (NLS1) galaxies from the Faint Images of the Radio Sky at Twenty-centimeters (FIRST) of the Very Large Array (VLA), which increases…
We use the database from Paper III to quantify the global and nuclear properties of emission-line nuclei in the Palomar spectroscopic survey of nearby galaxies. We show that the host galaxies of Seyferts, LINERs, and transition objects…
Narrow-line Seyfert 1 galaxies (NLS1s) are arguably one of the key AGN subclasses in investigating the origin of the black hole mass - stellar velocity dispersion (M-sigma) relation because of their high accretion rate and significantly low…
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…
We present four radio-loud NLS1 galaxies with extreme emission-line shifts, indicating radial outflow velocities of the ionized gas of up to 2450 km/s, above the escape velocity of the host galaxies. The forbidden lines show strong…
We present measurements of AGN type 1 luminosity function in the forbidden line [OIII]5007\AA using data from SDSS DR7. A special attention is paid to a subclass of Seyfert galaxies - the Narrow-Line Seyfert galaxies. These galaxies have…
In this work we aim at addressing the still open question about the nature of Narrow-Line Seyfert 1 (NLS1) galaxies: are they really active nuclei with lower mass Black-Holes (BHs) than Seyfert 1 (S1) and quasars? Our approach is based on…