Related papers: X-ray fluorescent lines from the Compton-thick AGN…
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…
We analyze the Spitzer spectra of 140 active galactic nuclei (AGN) detected in the hard X-rays (14-195 keV) by the Burst Alert Telescope (BAT) on board Swift. This sample allows us to probe several orders of magnitude in black hole masses…
We have investigated the nature and origin of the Fe K emission lines in Mrk~205 using observations with {\it Suzaku} and {\it XMM-Newton}, aiming to resolve the ambiguity between a broad emission line and multiple unresolved lines of…
It has been suggested that the narrow cores of the Fe K$\alpha$ emission lines in Active Galactic Nuclei (AGNs) are likely produced in the torus, the inner radius of which can be measured by observing the lag time between the $V$ and $K$…
We present the XMM-Newton observation of the merging system IRAS 19254-7245, also known as The Superantennae, whose southern nucleus is classified as a Seyfert 2 galaxy. The XMM-Newton data have allowed us to perform a detailed X-ray…
We conduct X-ray reverberation mapping and spectral analysis of the radio galaxy Centaurus A to uncover its central structure. We compare the light curve of the hard X-ray continuum from Swift Burst Alert Telescope observations with that of…
We investigate the nature of the faint X-ray source population through X-ray spectroscopy and variability analyses of 136 AGN detected in the 2 Ms Chandra Deep Field-North survey with > 200 background-subtracted 0.5-8.0 keV counts…
During the commissioning of the James Webb Space Telescope (JWST), the mid-infrared instrument (MIRI) observed NGC6552 with the MIRI Imager and the medium-resolution spectrograph (MRS). NGC6552 is an active galactic nucleus (AGN) at…
We present results of new ASCA observations of the low-luminosity AGN (LLAGN) NGC 4579 obtained on 1998 December 18 and 28, and we report on detection of variability of an iron K emission line. The X-ray luminosities in the 2--10 keV band…
We report the detection of a narrow Fe-K emission line in the Seyfert 1 galaxy NGC 5548 with the Chandra High-Energy Transmission Gratings. In the galaxy frame we measure a center energy of 6.40 \pm 0.03 keV, a FWHM of 4515 (+3525,-2645)…
Compton-thick active galactic nuclei (CT-AGNs), defined by column density $\mathrm{N_H} \geqslant 1.5 \times 10^{24} \ \mathrm{cm}^{-2}$, are so heavily absorbed that their X-ray emission is often feeble, even undetectable by X-ray…
We present new results from a Chandra HETG observation of NGC 5548 and give a comparison of absorption and emission features found in other Seyfert 1 galaxies using Chandra grating observations. Deep soft X-ray edges are seen in Mkn 509 and…
We present the soft X-ray spectrum of the LINER galaxy M81 derived from a long observation with the XMM RGS. The spectrum is dominated by continuum emission from the active nucleus, but also contains emission lines from Fe L, and H-like and…
Molecular clouds in the Galactic center (GC) reprocess radiation from past outbursts of nearby high-energy sources, generating a bright Fe K-alpha fluorescence at 6.4 keV. The closest clouds to the GC are only $\simeq 1.5$ pc from Sgr A*,…
We present XMM-Newton observations of three AGN taken as part of a hunt to find very heavily obscured Compton-thick AGN. For obscuring columns greater than 10^25 cm^-2, AGN are only visible at energies below 10 keV via reflected/scattered…
We report on Chandra X-ray observations of four narrow-line quasar candidates at z~6, selected from the SHELLQs project, based on the Subaru Hyper Suprime-Cam survey. These objects are characterised by narrow (FWHM<310 km/s), luminous…
We present a new method to predict the line-of-sight column density (NH) values of active galactic nuclei (AGN) based on mid-infrared (MIR), soft, and hard X-ray data. We developed a multiple linear regression machine learning algorithm…
A large population of heavily obscured, Compton Thick AGNs is predicted by models of galaxy formation, models of Cosmic X-ray Background and by the ``relic'' super-massive black-hole mass function measured from local bulges. However, so far…
We examine the near-infrared (NIR) emission from low-luminosity AGNs (LLAGNs). Our galaxy sample includes 15 objects with detected 2-10 keV X-ray emission, dynamical black hole mass estimates from the literature, and available Gemini/NIFS…
We present results from an XMM-Newton observation of the nearby Seyfert 2 galaxy NGC5643. The nucleus exhibits a very flat X-ray continuum above 2 keV, together with a prominent K-alpha fluorescent iron line. This indicates heavy…