相关论文: Active Galactic Nuclei Emission-Line Properties Ve…
(Abridged) Narrow Line Seyfert 1 (NLS1) galaxies have low mass black holes and mass accretion rates close to (or exceeding) Eddington, so a standard blackbody accretion disc should peak in the EUV. However, the lack of true absorption…
We report on the spectroscopic study of 19 low luminosity Flat Radio Spectrum (LL FRS) sources selected from Marcha's et al. (1996) 200 mJy sample. In the optical, these objects are mainly dominated by the host galaxy starlight. After…
The depth and coverage of the first years of JWST observations have revealed low luminosity active galactic nuclei (AGN) across a wide redshift range, shedding light on black hole (BH) assembly and feedback. We present our spectroscopic…
We present a comparative study of the physical properties of a homogeneous sample of 144 Narrow line Seyfert 1 (NLSy1) and 117 Broad-line Seyfert 1 (BLSy1) galaxies. These two samples are in a similar luminosity and redshift range and have…
Observations with the James Webb Space Telescope (JWST) have uncovered a substantial population of high-redshift broad-line active galactic nuclei (BLAGNs) characterized by moderate luminosities, weak X-ray emissions, and faint…
Flat-spectrum radio-loud Narrow-Line Seyfert 1 galaxies (NLS1s) are a recently discovered class of $\gamma$-ray emitting Active Galactic Nuclei (AGN), that exhibit some blazar-like properties which are explained with the presence of a…
We investigate the relation between X-ray nuclear emission, optical emission line luminosities and black hole masses for a sample of 47 Seyfert galaxies. The sample, which has been selected from the Palomar optical spectroscopic survey of…
We combine emission line and X-ray luminosities for 45 sources from the Chandra Deep Field South (CDF-S), and seven HELLAS sources, to obtain a new sample of 52 X-ray selected type-II active galactic nuclei (AGNs). Eighteen of our sources…
We present a sample of 930 intermediate-mass black hole (IMBH) active galactic nuclei (AGNs) with black hole masses of $M_\mathrm{BH} \leqslant 2 \times 10^{6}$ M$_{\odot}$, uniformly selected from the Seventeenth Data Release of the Sloan…
We present near- and mid-infrared spectra of eight Low-Luminosity Active Galactic Nuclei (LLAGN), spanning nearly four orders of magnitude in black hole mass and Eddington ratio, obtained with JWST/NIRSpec and MIRI as part of the ReveaLLAGN…
We report on a multiwavelength survey of a sample of 42 flat-spectrum radio-loud narrow-line Seyfert 1 galaxies (RLNLS1s). This is the largest known sample of this type of active galactic nucleus (AGN) to date. We found that 17% of sources…
Understanding the relationship between supermassive black holes (SMBHs) and their host galaxies at different redshifts is crucial for unraveling the processes of SMBH-galaxy co-evolution. We present the properties of nine type 1 Active…
We present optical images of nearby 50 narrow-line Seyfert 1 galaxies (NLS1s) which cover all the NLS1s at z<0.0666 and $\delta \ge -25^{\circ}$ known at the time of 2001. Among the 50 NLS1s, 40 images are newly obtained by our observations…
Narrow-Line Seyfert 1 galaxies (NLS1s) and Narrow-Line quasars (NLQs) seem to amount to ~ 10-30 % of active galactic nuclei (AGNs) in the local universe. Together with their average accretion rate, we argue that the black hole (BH) growth…
We use homogeneous samples of radio-quiet Seyfert 1 galaxies and QSOs selected from the Sloan Digital Sky Survey to investigate the connection between the velocity shift and the equivalent width (EW) of the [OIII] 5007 emission line, and…
Quasars accretion models predict a broad range of optical and ultraviolet properties that depend primarily on black hole mass and accretion rate. Yet, most optically selected luminous quasars display strikingly similar continuum spectra. We…
In the past few years more and more pieces of evidence have been presented for a revision of the widely accepted Unified Model of Active Galactic Nuclei. A model based solely on orientation cannot explain all the observed phenomenology. In…
In a sample of 476931 NELGs obtained from the SDSS DR5 data we find that in 22% of the galaxies the emission line [OIII]$\lambda$5007, H$\beta$, or both, are missing. The nature of the activity in these galaxies was determined using a…
Recent ROSAT studies of narrow-line Seyfert 1 galaxies revealed these objects (with FWHM $H_{\beta} \le 2000 km s^{-1}$) generally show steeper soft X-ray spectra than broad line Seyfert 1's and that there are no AGN with broad lines and…
Based on a new spectroscopic sample observed using the WHT, we examine the kinematic properties of the various emission line regions in narrow line Seyfert 1 galaxies (NLS1s) by modelling their profiles using multiple component fits. We…