Related papers: Variable Intrinsic Absorption in Mrk 279
We present analysis and photoionization modeling of the Chandra high resolution spectrum of Mrk 279. There is clear evidence of an absorbing outflow which is best fit by a two component model, one with a low ionization parameter and one…
We present an analysis of all the archival high resolution spectra of the Narrow-line Seyfert 1 galaxy Mrk~335 obtained with Reflection Grating Spectrometer (RGS) on board \textit{XMM-Newton}. The spectra show rich emission and absorption…
We present an investigation into the absorber in front of the z=2.63 radio galaxy MRC 2025-218, using integral field spectroscopy obtained at the Very Large Telescope, and long slit spectroscopy obtained at the Keck II telescope. The…
Between July 2012 and February 2013, NuSTAR and XMM-Newton performed four long-look joint obser- vations of the type 1.8 Seyfert, NGC 1365. We have analyzed the variable absorption seen in these observations in order to characterize the…
We present a systematic investigation of X-ray spectral variability of Seyfert 1 galaxies using a ``spectral-ratio model fitting'' technique, which we developed to estimate contribution of the putative clumpy absorbers to the spectral…
We re-analyzed the 9 observations performed on 2006 by XMM-Newton and Chandra in the 0.3 to 10 keV energy band of NGC 3516 (Seyfert 1.5). The best fit model of these observations consists of a continuum emission absorbed by four ionized…
We present new Hubble Space Telescope (HST)/Cosmic Origins Spectrograph observations of the Narrow-Line Seyfert 1 galaxy NGC 4051. These data were obtained as part of a coordinated observing program including X-ray observations with the…
This paper reports dual-epoch, Very Long Baseline Array observations of H I absorption toward 3C 147. One of these epochs (2005) represents new observations while one (1998) represents the reprocessing of previous observations to obtain…
An XMM-Newton observation of the luminous Seyfert 1 galaxy 1H 0419-577 in September 2002, when the source was in an extreme low-flux state, found a very hard X-ray spectrum at 1-10 keV with a strong soft excess below ~1 keV. Comparison with…
Accretion onto supermassive black hole (SMBH) can release energy via radiation, jets or winds, providing feedback effects on the circumnuclear gas environment. However, not all active galactic nuclei (AGNs) exhibit clear signature of such…
High-quality Far-Ultraviolet Spectroscopic Explorer (FUSE) observations at 20 km /s resolution of interstellar and intergalactic absorption from 910 to 1187 A are presented for the X-ray bright BL Lac object Mrk 421. In this study we…
We analyze 37 RXTE observations of the type 2 Seyfert galaxy Mrk348 obtained during a period of 14 months. We confirm the spectral variability previous reported by Smith et al., in the sense that thecolumn density decreases by a factor of…
We present a flux-resolved X-ray analysis of the dwarf Seyfert 1.8 galaxy NGC 4395, based on three archival $XMM-Newton$ and one archival $NuSTAR$ observations. The source is known to harbor a low mass black hole ($\sim 10^4- {\rm a~…
We present a study of X-ray column density variability in Seyfert 2 galaxies. We show that variations in N_H are observed in almost all the objects with multiple hard X-ray observations. Variation timescales (as short as a few months in…
We study the column densities of neutral atomic, molecular, and warm ionized Galactic gas through their continuous absorption of extragalactic X-ray spectra at |b| > 25 degrees. For N(H,21cm) < 5x10^20 cm^-2 there is an extremely tight…
We report the discovery of an occultation event in the low-luminosity narrow-line Seyfert 1 galaxy WPVS 007 in 2015 February and March. In concert with longer timescale variability, these observations place strong constraints on the nature…
Many Seyfert galaxies are known to exhibit significant X-ray spectral variations and seemingly broad iron K-emission line features. In this paper, we show that the "variable partial covering model", which has been successfully proposed for…
Broad Absorption Line Quasars (BALQs) are actively accreting supermassive black holes that have strong outflows characterized by broad absorption lines in their rest-UV spectra. Variability in these absorption lines occurs over months to…
We present far-ultraviolet spectra of the Seyfert 1.5 galaxy NGC 5548 obtained in 2000 June with the Far Ultraviolet Spectroscopic Explorer (FUSE). Our data span the observed wavelength range 915--1185 Angstroms at a resolution of 20 km/s.…
Recent submillimeter observations have revealed signs of pc-scale molecular inflow and atomic outflow in the nearest Seyfert 2 galaxy, the Circinus galaxy. To verify the gas kinematics suggested by these observations, we performed molecular…