相关论文: Catching NGC4051 in the low state with XMM-Newton

We report the results from a Chandra TOO observation of the low-luminosity Narrow Line Seyfert 1 galaxy NGC 4051, obtained during a 6-week duration low-flux state in 2001 February. During the Chandra observation, the 2-10 keV source flux…

The Narrow Line Seyfert 1 galaxy NGC 4051 was observed in one of its prolonged low-lux states by XMM-Newton in November 2002. Here we present the results of an analysis of EPIC-pn data obtained during the observation. Within the low state,…

Archival XMM-Newton data on the nearby Seyfert galaxy NGC 4051, taken in relatively high and low flux states, offer a unique opportunity to explore the complexity of its X-ray spectrum. We find the hard X-ray band to be significantly…

Soft X-rays high resolution spectroscopy of obscured AGNs shows the existence of a complex soft $X$-ray spectrum dominated by emission lines of He and H-like transitions of elements from Carbon to Neon, as well as L-shell transitions due to…

We study the X-ray spectral variability of the Narrow Line Seyfert 1 galaxy NGC 4051 as observed during two XMM-Newton observations. The data show evidence for a neutral and constant reflection component and for constant emission from…

An extended XMM-Newton observation of the Seyfert 1 galaxy NGC 4051 has revealed a rich absorption line spectrum indicating the presence of a photoionized outflow with a wide range of velocities and ionization parameter. At low continuum…

On 9-11 May 1998, the highly-variable, low luminosity Seyfert 1 galaxy NGC4051 was observed in an unusual low flux state by BeppoSAX (Guainazzi et al. 1998) RXTE and EUVE. We present fits of the 4-15 keV RXTE spectrum and BeppoSAX MECS…

NGC 4051 is one of the X-ray brightest and most variable Seyfert galaxies. During 2009 NGC 4051 was caught at its lowest state ever observed by $XMM-Newton$. The low source continuum emission allows a clear measurement of the He-like…

We present and analyze a pointed ROSAT PSPC observation of the Seyfert galaxy NGC 4051. The X-ray spectrum consists of a powerlaw modified by absorption edges and an additional soft excess during the high-state in source flux. Modeling the…

The Narrow-line Seyfert 1 galaxy NGC 4051 is known to exhibit significant X-ray spectral/flux variations and have a number of emission/absorption features. X-ray observations have revealed that these absorption features are blueshifted,…

We study the absorption and emission properties of the photoionised gas near one of the brightest and most variable AGN, the Seyfert galaxy NGC 4051, in order to constrain the geometry, dynamics and ionisation structure of the outflow. We…

We report results from a Suzaku observation of the narrow-line Seyfert 1 NGC 4051. During our observation, large amplitude rapid variability is seen and the averaged 2--10 keV flux is 8.1x10^-12 erg s^-1 cm^-2, which is several times lower…

We report on the X-ray spectral variability of the Seyfert 1 galaxy NGC 4051 observed with the Rossi X-ray Timing Explorer (RXTE) during a 1000 day period between May 1996 and March 1999. The spectra were obtained as part of monitoring…

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 the first detection of a sharp spectral feature in a Narrow-Line Seyfert 1 galaxy. Using XMM-Newton we have observed 1H0707-495 and find a drop in flux by a factor of more than 2 at a rest-frame energy of ~7 keV without any…

We present a comprehensive examination of the X-ray variability of the narrow line Seyfert 1 (NLS1) galaxy NGC4051. We combine over 6.5 years of frequent monitoring observations by RXTE with a >100ks continuous observation by XMM-Newton and…

We present XMM-Newton RGS observations of the soft X-ray spectrum of NGC 4051, and explore their implications for the inner accretion disk and ionized outflow in the active galactic nucleus. We fit the soft X-ray excess with a…

Methods. We analyse two observations taken with the Low Energy Transmission Grating Spectrometer of Chandra. We investigated the spectral response to a sudden flux decrease by a factor of 5, which occurred during the second observation.…

An extended XMM-Newton observation of the Seyfert I galaxy NGC 4051 in 2009 revealed a complex absorption spectrum, with a wide range of outflow velocities and ionisation states.The main velocity and ionisation structure was interpreted in…

BeppoSAX observed the low-luminous Seyfert 1 Galaxy NGC4051 in a ultra-dim X-ray state. The 2-10 keV flux (1.26 x 10^{-12} erg/cm^2/s) was about 20 times fainter than its historical average value, and remained steady along the whole…