Related papers: CLASS: Coronal Line Activity Spectroscopic Survey
We have analyzed high-resolution X-ray spectra of a sample of 22 active stars observed with the High Energy Transmission Grating Spectrometer on {\em Chandra} in order to investigate their coronal plasma density. Densities where…
Coronal-Line Forest Active Galactic Nuclei (CLiF AGN) are characterized by strong high-ionization lines, which contrast to what is found in most AGNs. Here, we carry out a multiwavelength analysis aimed at understanding the physical…
Tidal disruption of stars by supermassive black holes at the centers of galaxies is expected to produce unique emission line signatures, which have not yet been explored adequately. Here we report the discovery of extremely strong coronal…
We investigated by means of MUSE/VLT observations the true size of the coronal line region (CLR) in a local sample of nine active galactic nuclei known for displaying prominent coronal emission. Our analysis show that the CLR is extended…
We have studied the X-ray nuclear activity of 187 nearby (distance < 15 Mpc) galaxies observed with Chandra/ACIS. We found that 86 of them have a point-like X-ray core, consistent with an accreting black hole (BH). We argue that the…
We present the first spatially resolved investigation of near-infrared coronal lines in dwarf galaxies hosting active galactic nuclei (AGN), using JWST/NIRSpec integral field spectroscopy. Coronal lines (CLs), which are forbidden…
We announce a new facility in the spectral code CLOUDY that enables tracking the evolution of a cooling parcel of gas with time. For gas cooling from temperatures relevant to galaxy clusters, earlier calculations estimated the [Fe XIV]…
We report the new finding that type 1 Seyfert nuclei (S1s) have excess [FeVII]6087 emission with respect to type 2s (S2s). The S1s exhibit broad emission lines which are attributed to ionized gas within 1 pc of the black hole, whereas the…
Our Galaxy harbours a large population of X-ray sources of intermediate to low X-ray luminosity (typically Lx from 10^27 to 10^34 erg/s). At energies below 2 keV, active coronae completely dominate the X-ray landscape. However, the nature…
We present a reverberation mapping analysis of the coronal line [Ne V]$\lambda$3427 emitting region of the quasar COS168 (SDSS J095910.30+020732.2). [Ne V]$\lambda$3427 is known as one of the "coronal lines," which are a species of emission…
VLT and NTT spectra are used to examine the nuclear and extended coronal line emission in a sample of well-known Seyfert 1 and 2 galaxies. The excellent spatial resolution obtained with VLT allowed us to map [SiVI] 1.963 $\mu$m and [SiVII]…
Chandra has detected optically thin, thermal X-ray emission with a size of ~1 arcsec and luminosity ~10^33 erg/s from the direction of the Galactic supermassive black hole (SMBH), Sgr A*. We suggest that a significant or even dominant…
We present 3.5m Apache Point Observatory second-epoch spectra of four low-metallicity emission-line dwarf galaxies discovered serendipitously in the Data Release 5 of the Sloan Digital Sky Survey (SDSS) to have extraordinary large broad…
We present the BAT AGN Spectroscopic Survey (BASS) Near-infrared Data Release 2 (DR2), a study of 168 nearby ($\bar z$ = 0.04, $z$ < 0.6) active galactic nuclei (AGN) from the all-sky Swift Burst Array Telescope X-ray survey observed with…
Images taken in the band centered at 30.4 nm are routinely used to map the radiance of the He II Ly alpha line on the solar disk. That line is one of the strongest, if not the strongest, line in the EUV observed in the solar spectrum, and…
X-ray-emitting coronae of nearby galaxies are expected to be produced either by accretion from the intergalactic medium and/or by various galactic feedback. We herein present a systematical analysis of the Chandra observations of 53 nearby…
This work presents the first results of the Deep IFS View of Nuclei of Galaxies (DIVING$^\mathrm{3D}$) survey. We analysed the nuclear emission-line spectra of a sub-sample we call mini-DIVING$^\mathrm{3D}$, which includes all Southern…
We performed statistical and event studies of linear polarization in the H$\alpha$ line during solar flares. The statistical study revealed that, among 71 H$\alpha$ flares analyzed, including 64 GOES flares, only one event shows significant…
We present the first extensive study of the coronal line variability in an active galaxy. Our data set for the nearby source NGC 4151 consists of six epochs of quasi-simultaneous optical and near-infrared spectroscopy spanning a period of…
We have investigated the optical thickness of the coronal plasma through the analysis of high-resolution X-ray spectra of a large sample of active stars observed with the High Energy Transmission Grating Spectrometer on Chandra. In…