101 datasets found

We examine the UV/X-ray properties of 1378 quasars in order to link empirical correlations to theoretical models of the physical mechanisms dominating quasars as a function of...

The dense central regions of tidally disrupted galaxies can survive as ultracompact dwarfs (UCDs) that hide among the luminous globular clusters (GCs) in the halo of massive...

Under the hypothesis of gravitational redshift induced by a central supermassive black hole, and based on line widths and shifts of redward-shifted H{beta} and FeII broad...

The origin of jets is one of the most important issues concerning active galactic nuclei, yet it has remained obscure. In this work, we made use of information from emission...

Searches for electromagnetic counterparts of gravitational-wave signals have redoubled since the first detection in 2017 of a binary neutron star merger with a gamma-ray burst,...

We report the results of near-infrared spectroscopic observations of 37 quasars in the redshift range 6.3<z<=7.64, including 32 quasars at z>6.5, forming the largest...

We present optical follow-up imaging obtained with the Katzman Automatic Imaging Telescope, Las Cumbres Observatory Global Telescope Network, Nickel Telescope, Swope Telescope,...

Blazar PG 1553+113 is thought to be a host of supermassive black hole binary system. A 2.2yr quasi-periodicity in the {gamma}-ray light curve was detected, possibly a result of...

While radio emission in quasars can be contributed to by a variety of processes (involving star-forming regions, accretion disk coronas and winds, and jets), the powering of the...

The massive black hole (BH) population in dwarf galaxies (M_BH_<~10^5^M_{sun}) can provide strong constraints on the origin of BH seeds. However, traditional optical searches...

We report the results of a multiyear spectroscopic and photometric monitoring campaign of two luminous quasars, PG0923+201 and PG1001+291, both located at the high-luminosity...

We measure a strong excess in the galaxy number density around PG1630+377, an extremely massive (MBH~109.7M{sun}) quasar at z=1.475, using near-infrared narrowband imaging. We...

AT2019wey (SRGA J043520.9+552226, SRGE J043523.3+552234) is a transient first reported by the ATLAS optical survey in 2019 December. It rose to prominence upon detection, three...

The Super-Kamiokande detector can be used to search for neutrinos in time coincidence with gravitational waves detected by the LIGO-Virgo Collaboration (LVC). Both low-energy...

We constrained the progenitor masses for 169 supernova remnants (SNRs), eight historically observed supernovae (SNe), and the black hole formation candidate in NGC 6946, finding...

We present optical follow-up observation results of three binary black hole merger (BBH) events, GW190408_181802, GW190412, and GW190503_185404, which were detected by the...

We search for gravitational-wave transients associated with gamma-ray bursts (GRBs) detected by the Fermi and Swift satellites during the first part of the third observing run...

Supermassive black hole binaries (SMBHBs) should form frequently in galactic nuclei as a result of galaxy mergers. At subparsec separations, binaries become strong sources of...

We revisit the dependence of the covering factor (CF) of dust torus on physical properties of active galactic nuclei (AGNs) by taking into account an AGN polar dust emission....

We present StrayCats, a catalog of Nuclear Spectroscopic Telescope ARray (NuSTAR) stray light observations of X-ray sources. Stray light observations arise for sources...