相关论文: The Variable Warm Absorber in Circinus X-1

We combine emission line and X-ray luminosities for 45 sources from the Chandra Deep Field South (CDF-S), and seven HELLAS sources, to obtain a new sample of 52 X-ray selected type-II active galactic nuclei (AGNs). Eighteen of our sources…

We present the first detection of carbon radio recombination line absorption along the line of sight to Cygnus A. The observations were carried out with the LOw Frequency ARray in the 33 to 57 MHz range. These low frequency radio…

This paper is a sequel to the extensive study of warm absorber (WA) in X-rays carried out using high resolution grating spectral data from XMM-Newton satellite (WAX-I). Here we discuss the global dynamical properties as well as the…

We present an analysis of an XMM-Newton observation of the Seyfert 1 Galaxy NGC 985. The EPIC spectra present strong residuals to a single power-law model, indicating the presence of ionized absorbing gas and a soft excess. A broad-band fit…

In this work, the analysis of multi-epoch (1995-2010) X-ray observations of the Seyfert 1 galaxy H0557-385 is presented. The wealth of data presented in this analysis show that the source exhibits dramatic spectral variability, from a…

I present a study of the X-ray spectral properties of a sample containing 24 type-1 active galactic nuclei using the medium spectral resolution of ``ASCA''. The sample consists of 20 radio-quiet objects and 4 radio-loud objects. A simple…

We have monitored the massive binary star $\eta$ Carinae with the CTIO/SMARTS 1.5~m telescope and CHIRON spectrograph from the previous apastron passage of the system through the recent 2014.6 periastron passage. Our monitoring has resulted…

Warm absorption is a common phenomenon in Seyfert 1s and quasars, but rare in Seyfert 2s. In this paper, we report the detection of warm absorbers with high energy resolution in the Seyfert 2 galaxy IRAS 18325-5926 for the first time with…

We report the detection of rapid wavelength and intensity variations of narrow components in absorption line profiles of the hot galactic supergiant P Cygni. During most of the time, in one week of observations, there were two such…

We have analyzed all available archival XMM-Newton observations of X Comae, a bright X-ray quasar behind the Coma cluster, to study the properties of the warm-hot intergalactic medium in the vicinity of the nearest massive galaxy cluster.…

We present observations of the UV absorption lines in the Seyfert 1 galaxy NGC 3516, obtained at a resolution of $\lambda$/$\Delta\lambda$ $\approx$ 40,000 with the Space Telescope Imaging Spectrograph (STIS) on 2000 October 1. The UV…

We present the results of a 200 ks Chandra observation of part of the Groth Strip region, using the ACIS-I instrument. We present a relatively simple method for the detection of point-sources and calculation of limiting sensitivities, which…

We present an X-ray absorption line spectroscopic study of the large-scale hot interstellar medium (HISM) in the Galaxy. We detect Ne IX K$_\alpha$ absorption lines in the {\sl Chandra} grating spectra of seven Galactic low-mass X-ray…

The presence of a ``warm absorber'' was first suggested to explain spectral variability in an X-ray spectrum of the radio-quiet QSO MR2251-178. A unified picture, in which X-ray warm absorbers and ``intrinsic'' UV absorbers are the same,…

Warm absorber (WA) is an ionised gas present in the line of sight to the AGN central engine. The effect of the absorber is imprinted in the absorption lines observed in X-ray spectra of AGN. In this work, we model the WA in Seyfert 1 galaxy…

We observed 1E 1207.4--5209, a neutron star in the center of the supernova remnant PKS 1209--51/52, with the ACIS detector aboard the Chandra X-ray observatory and detected two absorption features in the source spectrum. The features are…

The super-soft source (SSS) phase of a nova eruption, observed a few days after the outburst, usually displays an absorbed X-ray thermal continuum with absorption features, emitted by the white dwarf (WD) atmosphere. However, the X-ray…

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.…

We present almost-simultaneous detections of Cygnus X-1 in the radio and mm regimes, obtained during the low/hard X-ray state. The source displays a flat spectrum between 2 and 220 GHz, with a spectral index flatter than 0.15 (3sigma).…

Infrared carbon stars without visible counterparts are generally known as extreme carbon stars. We have selected a subset of these stars with absorption features in the 10-13 $\mu$m range, which has been tentatively attributed to silicon…