Related papers: Kinematic differences between NLS1 and BLAGN sourc…
We have conducted a multiwavelength survey of 42 radio loud narrow-1ine Seyfert 1 galaxies (RLNLS1s), selected by searching among all the known sources of this type and omitting those with steep radio spectra. We analyse data from radio…
Narrow-Line Seyfert 1 galaxies (NLS1s) are generally believed to be radio-quiet Active Galactic Nuclei (AGN) with relatively less-massive (10$^{5}$$-$10$^{8}$~M$_{\odot}$) Super-Massive Black Holes (SMBH). Using the FIRST radio detections…
The optical spectra of 3,896 Seyfert~1 (Sy1) galaxies detected with WISE at z < 0.4 were analyzed for evidence of outflows. In 37% of the Sy1s the outflows appear as broad, blue-shifted, of the [OIII]5007, with a mean maximum velocity V_max…
$\gamma$-ray-emitting narrow-line Seyfert 1 galaxies ($\gamma$-NLS1) constitute an intriguing small population of Active Galactic Nuclei with $\gamma$-ray emission resembling low power flat-spectrum radio quasars (FSRQ), but with differing…
Massive Black Holes detected in the centers of many nearby galaxies show an approximately linear relation with the luminosity of the host bulge, with the black hole mass being 0.001-0.002 of the bulge mass. Previous work suggested that…
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…
Narrow-line Seyfert 1 (NLS1) galaxies are active galactic nuclei (AGN) believed to be in the early stages of their evolution. A fraction of them have been found to host relativistic jets. Due to the lack of large-scale diffuse radio…
I briefly review the X/UV absorber models and show that the observations of NLS1s are generally consistent with the models. The covering factor of absorbers in NLS1s is likely to be high and there is some evidence of super-solar…
(abridged) We present a comprehensive study of a sample of 23 genuine radio-loud NLS1 galaxies which have the radio-loudness parameters greater than 100. The radio sources of the sample are ubiquitously compact. A significant fraction of…
We present a study of the nuclear morphology of a sample of narrow- and broad-line Seyfert 1 galaxies (NLS1's and BLS1's) based on broad-band images in the Hubble Space Telescope archives. In our previous study, we found that large-scale…
The masses of central supermassive black holes in a soft X-ray selected sample of the narrow-line Seyfert 1 galaxies (NLS1s) are estimated by some different methods to test their theoretical models. Apart from the methods using the H$\beta$…
The effect of the observed continuum emitted from a relativistic jet on the measurement of the full width half maximum (FWHM) of an emission line is analyzed. If the jet contribution is not properly subtracted, the FWHM of the line could…
It is becoming clear that we can define two different types of nearby AGN belonging to the Seyfert 1 class (S1), on the basis of the match of the intensities of their Broad Balmer Lines (BBL) with the Boltzmann Plots (BP). These two types…
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…
The {\gamma}-ray detection from several radio-loud (RL) narrow-line Seyfert 1 (NLS1) galaxies has enabled us to study powerful relativistic jets in active galactic nuclei (AGNs) with smaller black hole masses and higher accretion rates than…
In the last decade of Active Galactic Nuclei (AGN) monitoring programs, the Mets\"ahovi Radio Observatory detected multiple times seven powerful flaring narrow-line Seyfert 1 (NLS1) galaxies at 37 GHz. Several hypotheses have been proposed,…
In order to investigate how the growth of galactic bulges progresses with the growth of central black holes (BHs), we observed molecular gas (fuel for the coming star formation) in possibly young active galaxies, narrow-line Seyfert 1…
The last decade has witnessed a steadily increasing number of observational studies concerning the rare class of radio loud narrow-line Seyfert 1 galaxies, of which several hundred are currently known. According to the current AGN paradigm,…
The gamma-ray emitting narrow-line Seyfert 1 galaxies are a unique class of objects that launch powerful jets from relatively lower-mass black hole systems compared to the Blazars. However, the black hole masses estimated from the total…
We report the observation of features near 1 keV in the ASCA spectra from three ``Narrow Line Seyfert 1'' (NLS1) galaxies. We interpret these as oxygen absorption in a highly relativistic outflow. If interpreted as absorption edges, the…