Related papers: Coronal Line Emission from NLS1s

We present XMM-Newton, NuSTAR, Swift and Hubble Space Telescope observations of the Narrow-line Seyfert 1 galaxy Mrk 335 in a protracted low state in 2018 and 2019. The X-ray flux is at the lowest level so far observed, and the extremely…

We report identification of a narrow-line Seyfert 1 galaxy RXJ1236.9+2656. X-ray emission from the NLS1 galaxy undergoes long-term variability with 0.1--2.0 keV flux changing by a factor of 2 within about 3 yr. The ROSAT PSPC spectrum of…

A cross-correlation of the SDSS DR7 with the FIRST radio survey makes it possible to conduct a joined multiwavelength statistical study of radio-optical galaxy properties on a very large number of sources. Our goal is to improve the study…

We present an analysis of the rms variability spectra of a sample of 18 observations of 14 Seyfert galaxies observed by XMM-Newton, which exhibit sufficient variability and signal-to-noise ratio to examine the variations in the iron K-band.…

XMM-Newton observations of the NLS1 Markarian 896 are presented. Over the 2-10 keV band, an iron emission line, close to 6.4 keV, is seen. The line is just resolved and has an equivalent width of ~170 eV. The broad-band spectrum is well…

We aim to characterize the nature of galaxies whose optical emission line diagnostics are consistent with star formation, but whose X-ray properties strongly point towards the presence of an AGN. Understanding these sources is of particular…

Our aim is to explore the nature of emission line galaxies by combining high-resolution observations obtained in different bands to understand which objects are powered by an Active Galactic Nucleus(AGN). From the spectroscopic Palomar…

We identify a correlation space involving optical and UV emission line parameters as well as the soft X-ray spectral index that provides optimal discrimination between all principal classes of active galactic nuclei. Most of the sources in…

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…

As part of an extensive study of the physical properties of active galactic nuclei (AGN) we report high spatial resolution near-IR integral-field spectroscopy of the narrow-line region (NLR) and coronal-line region (CLR) of seven Seyfert…

We present the main results of broad band (0.1-10 keV) BeppoSAX observations of a selected sample of Narrow Line Seyfert 1 galaxies (NLS1s). We have performed a spectroscopic analysis of LECS and MECS data to test their average spectral…

We present multi-frequency radio data for a sample of narrow-line Seyfert 1 galaxies. We first focus on the sub-class of gamma-ray emitting narrow-line Seyfert 1 galaxies, studying the long-term radio variability of five sources and…

We present a new accurate catalog of narrow-line Seyfert 1 galaxies (NLS1s) in the southern hemisphere from the Six-degree Field Galaxy Survey (6dFGS) final data release, which is currently the most extensive spectroscopic survey available…

The observed spectral energy distributions of five GeV-selected narrow-line Seyfert 1 (NLS1) galaxies are fitted with a model including the radiation ingredients from the relativistic jet, the accretion disk, and the corona. We compare the…

Spatially resolved emission-line spectroscopy is a powerful tool to determine the physical conditions in the narrow-line region (NLR) of active galactic nuclei (AGNs). We recently used optical long-slit spectroscopy to study the NLRs of a…

Taking advantage of the most recent measurements by means of high-resolution radio observations and other multiwavelength campaigns, it is possible to elaborate a detailed map of the narrow-line Seyfert 1 Galaxy 1H 0323+342. This map will…

We use the data from a recent, 100 ksec XMM-Newton observation of the Narrow Line Seyfert 1 galaxy Ark 564 to obtain its time average, X-ray spectrum. The 3-11 keV spectrum is well fitted by a power-law of slope 2.43. We detect a weak…

We present a sample of 17 type 2 Seyfert galaxies which have an X-ray column density lower than 10^{22} cm^{-2}. The Compton thin nature of these sources is strongly suggested by isotropic indicators. We estimate the fraction of these…

We report on a study of long-term flux variations in a sample of more than 1000 AGN observed with ROSAT and in the XMM-Newton slew survey. Over a period of 3-19 years, NLS1 galaxies as a class are found to be only slightly more variable…

We have compiled a list of 83 objects classified as Narrow-Line Seyfert 1 galaxies (NLS1s) or known to have a broad Balmer component narrower than 2000 km/s. Out of these, 19 turned out to have been spectroscopically misidentified in…