251 datasets found

We select a sample of 1437 active galactic nuclei (AGN) from the catalog of the Sloan Digital Sky Survey galaxy properties from the Portsmouth group by detection of the...

Extreme sudden changes in the flow of accreting gas onto supermassive black holes manifest themselves via large-amplitude multiband continuum variability, as well as changes to...

The variability mechanisms from jetted active galactic nuclei (AGNs) are still under debate. Here, the damped random walk (DRW) model, implemented through Gaussian processes...

In this work, we present the first results of the long-term high-cadence spectroscopic monitoring of 15 PG quasars with relatively strong FeII emission, as a part of a broader...

We compiled a sample of 73 active galactic nuclei (AGNs) with reverberation mapping (RM) observations from RM campaigns, including our ongoing campaign of monitoring...

We report first results from a large project to measure black hole (BH) mass in high accretion rate active galactic nuclei (AGNs). Such objects may be different from other AGNs...

The Faint Object Camera (FOC) on board the Hubble Space Telescope (HST) acquired high-resolution spatially resolved polarimetric images of nearby active galactic nuclei (AGNs)...

The Subarcsecond mid-infrared (MIR) atlas of local active galactic nuclei (AGN) is a collection of all available N- and Q-band images obtained at ground-based 8-meter class...

To date, three nuclear transients have been associated with high-energy neutrino events. These transients are generally thought to be powered by tidal disruptions of stars...

These FITS images were generated with the IDL package MIRphot [Asmus2014] by extraction (and combination) of the sub-images from the chopped/nodded total images from COMICS,...

We describe the results of a new reverberation mapping program focused on the nearby Seyfert galaxy NGC 3227. Photometric and spectroscopic monitoring was carried out from 2022...

UBVRI observations of the nucleus of the Seyfert galaxy NGC 5548 from 1990 until 2000 at four astronomical observatories are given in Table2. All data have been reduced to a...

Broadband UBVRI observations of the nucleus of the Seyfert galaxy NGC 4151 from 1989 until 2000 at three astronomical observatories: the Crimean Station of the Sternberg...

Two CCD spectra of the star BM Ori were obtained with the echelle spectrograph of the 6-m telescope. Measured line equivalent widths were used to estimate atmospheric parameters...

The UBV observations of performed between 1972 and 1998 are presented. The aperture is 27.5".

Variability of the continuum, H{beta}, H{gamma} and HeII(4686{AA}) fluxes of the Seyfert I galaxy Mrk 509 is studied using spectra obtained on the 2.6-m telescope of the Crimean...

We obtained new quantitative determinations of the nitrogen abundance and a consistent relation between the nitrogen and oxygen abundances for a sample of Seyfert 2 galaxies...

We provide a comprehensive census of the near-infrared (NIR, 0.8-2.4um) spectroscopic properties of 102 nearby (z<0.075) active galactic nuclei (AGN), selected in the hard...

We present far-infrared (FIR) 70-500{mu}m imaging observations obtained with Herschel/Photodetector Array Camera (PACS) and Spectral and Photometric Imaging REceiver (SPIRE) of...

We present an updated mid-infrared (MIR) versus X-ray correlation for the local active galactic nuclei (AGN) population based on the high angular resolution 12 and 18{mu}m...