124 datasets found

We present ground-based and Swift photometric and spectroscopic observations of the candidate tidal disruption event (TDE) ASASSN-14li, found at the centre of PGC 043234 (d~90...

As an inaugural investigation under the X-ray Winds In Nearby-to-distant Galaxies (X-WING) program, we assembled a data set comprising 132 active galactic nuclei (AGNs) spanning...

We study the general physical properties of Fermi blazars using the Fermi fourth source catalog data (4FGL-DR2). The quasi-simultaneous multiwavelength data of Fermi blazars are...

This paper provides the compilations of properties of the quasars newly obtained by the Sloan Digital Sky Survey (SDSS) during the fourth stage (SDSS-IV). The catalog is...

We present measurements of broad emission lines and virial estimates of supermassive black hole masses (M_BH_) for a large sample of ultrahard X-ray-selected active galactic...

Quasars behind the Galactic plane (GPQs) are important astrometric references and valuable probes of Galactic gas, yet the search for GPQs is difficult due to severe extinction...

Despite their importance for astrometry and navigation, the active galactic nuclei (AGNs) that comprise the International Celestial Reference Frame (ICRF) are relatively poorly...

We present a catalog of central engine properties, i.e., black hole mass (M_BH_) and accretion luminosity (L_disk_), for a sample of 1077 blazars detected with the Fermi Large...

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...

Optical time-domain astronomy has grown rapidly in the past decade, but the dynamic infrared sky is rarely explored. Aiming to construct a sample of mid-infrared outbursts in...

We present the third catalog release of the wide-area (31.3deg^2^) Stripe 82 X-ray survey. This catalog combines previously published X-ray source properties with...

Transient accretion events onto supermassive black holes (SMBHs), such as tidal disruption events (TDEs), Bowen Fluorescence Flares (BFFs), and active galactic nuclei (AGNs),...

Weak emission-line quasars (WLQs) are a subset of type 1 quasars that exhibit extremely weak Ly{alpha}+NV{lambda}1240 and/or CIV{lambda}1549 emission lines. We investigate the...

The most reliable single-epoch supermassive black hole mass (MBH) estimates in quasars are obtained by using the velocity widths of low-ionization emission lines, typically the...

High-resolution X-ray observations offer a unique tool for probing the still-elusive connection between galaxy mergers and active galactic nuclei (AGNs). We present an analysis...

The LIGO/Virgo detected a gravitational wave (GW) event, named GW200224_222234 (also known as S200224ca) and classified as a binary-black hole coalescence, on 2020 February 24....

We collect a large sample with a reliable redshift detected by the Fermi satellite after 10yr of data (4FGL-DR2), including blazars, gamma-ray narrow-line Seyfert 1 galaxies...

Tidal disruption events (TDEs) offer a unique way to study dormant black holes. While the number of observed TDEs has grown thanks to the emergence of wide-field surveys in the...

We continue to explore the relationship between the total number of globular clusters (GCs), N_GC_, and the central black hole mass, M_BH_, in spiral galaxies. We present here...

The high-ionization mid-IR lines, excited in the narrow-line regions of active galactic nuclei (AGN), barely affected by stellar excitation and dust extinction, trace the AGN...