相关论文: The Fe II problem in NLS1s

X-ray variability is very common in active galactic nuclei (AGN), but these variations may not occur similarly in different families of AGN. We aim to disentangle the structure of low ionization nuclear emission line regions (LINERs)…

Large scale, weakly collimated outflows are very common in galaxies with large infrared luminosities. In complex systems in particular, where intense star formation (SF) coexists with an active galactic nucleus (AGN), it is not clear yet…

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…

Narrow Line Seyfert 1 galaxies (NLS1) are very interesting objects which display peculiar properties when compared to their broad line analogues (BLS1). Although well studied in many wavebands, their behaviour at >10 keV is poorly studied…

Active Galactic Nuclei (AGN) have long been known to be variable, but the amplitude, timescale and nature of these changes can often differ dramatically from object to object. The richest source of information about the properties of AGN…

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…

Modelling the low ionization lines (LIL) in active galactic nuclei still faces problems in explaining the observed equivalent widths (EWs). We examine the optical Fe II and near-infrared Ca II triplet (CaT) emission strengths using the…

The centre of NGC 4151 has been observed in the J-band with the SMIRFS integral field unit (IFU) on the UK Infrared Telescope. A map of [Fe II] emission is derived, and compared with the distributions of the optical narrow line region and…

We present multi-component photoionization models allowing for local density inhomogeneities in the NLR to interpret the emission line spectra of Seyfert 2 galaxies. This approach leads to a successful match of a large set of line…

New observations are reported of J-band spectra (1.04micron -- 1.4 micron) of three Seyfert 2 galaxies, Mkn 34, Mkn 78 and NGC 5929. In each case the spectral range includes the near-infrared lines of [FeII], [PII], HeI and Pa beta. Each…

A model for the inner regions of accretion flows is presented where, due to disc instabilities, cold and dense material is clumped into deep sheets or rings. Surrounding these density enhancements is hot, tenuous gas where coronal…

We present a reverberation analysis of the strong, variable optical Fe II emission bands in the spectrum of Akn 120, a low-redshift AGN which is one of the best candidates for such a study. On time scales of several years the Fe II line…

For the past 10 years there has been an active debate over whether fast shocks play an important role in ionizing emission line regions in Seyfert galaxies. To investigate this claim, we have studied the Seyfert 2 galaxy Mkn 78, using HST…

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 variability of optical FeII blends in NGC 4051 is examined from spectra extracted from the AGN Watch program.In our analysis, the FeII complex are subtracted and measured with the following results. Firstly, the FeII variations were…

The Fermi/LAT collaboration recently reported the detection of starburt galaxies in the high energy gamma-ray domain, as well as radio-loud narrow-line Seyfert 1 objects. Motivated by the presence of sources close to the location of…

X-ray spectral features which are unusually strong in many Narrow-Line Seyfert galaxies are found to be consistent with reflection from strongly ionized matter, providing further evidence of a high accretion rate in these objects and…

Many classes of active galactic nuclei (AGN) have been observed and recorded since the discovery of Seyfert galaxies. In this paper, we examine the sample of luminous galaxies in the Baryon Oscillation Spectroscopic Survey (BOSS). We find a…

Non-blazar Active Galactic Nuclei (AGN) have emerged as a new gamma-ray emitting source class on the extragalactic sky and started to deepen our understanding of the physical processes and the nature of AGN in general. The detection of…

We present an analysis of the subdwarf O star Feige 67 with a fully metal-line blanketed NLTE model atmosphere based on high-resolution Far-UV (912-2000 A) and Near-UV (2000-3400 A) spectra from new ORFEUS II echelle observations and the…