相关论文: Complex Narrow Line Seyfert 1s: High spin or high …

While a broad profile of the Fe K$\alpha$ emission line is frequently found in the X-ray spectra of typical Seyfert galaxies, the situation is unclear in the case of Narrow Line Seyfert 1 galaxies (NLS1s)---an extreme subset which are…

Relativistic reflection models of the X-ray spectrum of the `complex' Narrow Line Seyfert 1 (NLS1) 1H 0707-495 require a high spin, moderate inclination, low mass black hole. With these parameters fixed, the observed optical/UV emission…

We analyse the X-ray time-lags in the Narrow Line Seyfert 1 (NLS1) galaxy PG 1244+026 ($M_{\rm BH}\sim 10^7 M_{\rm sun}$, $L/L_{\rm Edd}\sim 1$). The time delay between the soft (0.3--0.7~keV) and harder (1.2--4.0~keV) variations shows…

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…

Narrow-line Seyfert 1 galaxies (NLS1s) are a subclass of active galactic nuclei (AGN). It is often believed that these AGN have small black hole mass, which is responsible for the narrowness of the permitted lines. They are also…

We study the origin of the soft X-ray excess seen in the 'simple' Narrow Line Seyfert 1 galaxy PG1244+026 using all available spectral-timing information. This object shows the standard switch between soft leading the hard band on long…

We explore the origin of the strong soft X-ray excess in Narrow Line Seyfert 1 galaxies using spectral-timing information from a 120ks {\it XMM-Newton} observation of PG 1244+026. Spectral fitting alone cannot distinguish between a true…

(abridged) With the commissioning of XMM came the discovery of 2.5-10 keV spectral complexity in some narrow-line Seyfert 1 galaxies (NLS1). In this work, we define two samples of NLS1: a complex sample whose members exhibit high-energy…

A detailed analysis of a long XMM-Newton observation of the Narrow Line Seyfert 1 galaxy 1H0707-495 is presented, including spectral fitting, spectral variability and timing studies. The two main features in the spectrum are the drop at ~ 7…

Results are presented from a 500ks long XMM-Newton observation of the Narrow-Line Seyfert 1 galaxy IRAS13224-3809. The source is rapidly variable on timescales down to a few 100s. The spectrum shows strong broad Fe-K and L emission features…

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…

The narrow Fe K$\alpha$ line is one of the main signatures of the reprocessing of X-ray radiation from the material surrounding supermassive black holes, and it has been found to be omnipresent in the X-ray spectra of active galactic nuclei…

We report on AGN with extremely soft X-ray spectra observed with ROSAT. From their optical emission lines these objects are classified as narrow-line Seyfert 1 galaxies (NLS1), almost all with extremely large Fe II/H-beta ratios and…

Narrow Line Seyfert 1 galaxies are generally accreting at high fractions of the Eddington limit. They can show complex X-ray spectra, with a strong `soft excess' below 2 keV and a sharp drop at ~7 keV. There is strong evidence linking the…

Narrow-Line Seyfert 1s (NLS1s) are generally considered to be strange Active Galactic Nuclei (AGNs). Surprisingly, this makes them very useful for constraining models. I discuss what happens when one attempts to qualitatively fit the NLS1…

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…

The X-ray spectra of luminous Seyfert 1 galaxies often appear to be reflection dominated. In a number of Narrow Line Seyfert 1 (NLS1) galaxies and galactic black holes in the very high state, the variability of the continuum and of the iron…

Narrow Line Seyfert 1 (NLSy1) galaxies are a peculiar class of type 1 AGN (BLSy1). The X-ray properties of individual objects belonging to this class are often extreme and associated with accretion at high Eddington ratios. Here we present…

High-frequency iron K reverberation lags, where the red wing of the line responds before the line centroid, are a robust signature of relativistic reflection off the inner accretion disc. In this letter, we report the discovery of the Fe K…

We revisited the spectroscopic characteristics of narrow-line Seyfert 1 galaxies (NLS1s) by analysing a homogeneous sample of 296 NLS1s at redshift between 0.028 and 0.345, extracted from the Sloan Digital Sky Survey (SDSS-DR7) public…