Related papers: Discovery of a 2 Kpc Binary Quasar
We present the analysis of OGLE-2016-BLG-0613, for which the lensing light curve appears to be that of a typical binary-lens event with two caustic spikes but with a discontinuous feature on the trough between the spikes. We find that the…
We searched for eclipses of two millisecond pulsars, PSR J1807-2459 and PSR B1908+00. These pulsars are in very low mass binary systems with orbital parameters similar to those of eclipsing binaries. Observations were made with the GBT at…
Binary pulsar systems are superb probes of stellar and binary evolution and the physics of extreme environments. In a survey with the Arecibo telescope, we have found PSR J1903+0327, a radio pulsar with a rotational period of 2.15 ms in a…
We have obtained follow-up observations of the quasar pair LBQS 0107-025A,B and new observations of the nearby quasar LBQS 0107-0232 with the Hubble Space Telescope Faint Object Spectrograph. Extended wavelength coverage of LBQS 0107-025A…
Multiple galaxies hosting active galactic nuclei (AGNs) at kiloparsec separation from each other are exceedingly rare, and in fact, only one quadruple AGN is known so far. These extreme density peaks are expected to pinpoint protocluster…
Galaxy pairs with separations of only a few kpc represent important stages in the merger-driven growth of supermassive black holes (SMBHs). However, such mergers are difficult to identify observationally due to the correspondingly small…
On May 21, 2019 at 03:02:29 UTC Advanced LIGO and Advanced Virgo observed a short duration gravitational-wave signal, GW190521, with a three-detector network signal-to-noise ratio of 14.7, and an estimated false-alarm rate of 1 in 4900 yr…
By discovering a narrow-line emitter embedded in an extended Ly-alpha nebula, Husemann et al. (2018) found that the luminous radio-quiet quasar LBQS 0302-0019 is a dual active galactic nucleus (AGN) system. By combining available archival…
HE 0141-3932 (zem = 1.80) is a bright blue radio-quite quasar with an unusually weak Ly-alpha emission line. Large redshift differences (Delta z = 0.05) are observed between high ionization and low ionization emission lines. Absorption…
We present deep imaging and spectroscopic observations of the z = 1.195 quasar 3C 190 and its immediate environment. The quasar is surrounded by an asymmetric low-surface-brightness envelope in which there are also several galaxies with…
We present the first fully relativistic longterm numerical evolutions of three equal-mass black holes in a system consisting of a third black hole in a close orbit about a black-hole binary. We find that these close-three-black-hole systems…
We draw the multimessenger picture of J1048+7143, a flat-spectrum radio quasar known to show quasi-periodic oscillations in the $\gamma$-ray regime. We generate the adaptively-binned Fermi Large Area Telescope light curve of this source…
Given their extremely large distances and small apparent sizes, quasars are generally considered as objects with near-zero parallax and proper motion. However, some special quasars may have abnormal astrometric characteristics, such as…
We present observations of SDSSp J104433.04--012502.2, a luminous quasar at z=5.80 discovered from Sloan Digital Sky Survey (SDSS) multicolor imaging data. This object was selected as an i'-band dropout object, with i*=21.8 +/- 0.2, z*=19.2…
We present the spectroscopic confirmation and lens modeling of HSC~J0233$-$0205, a strong-lensing system produced by a close pair of elliptical galaxies at $z_d=0.790\pm0.022$ that lenses a multi-component background source at…
We present HST/WFPC2 broadband and ground-based Halpha images, H I 21-cm emission maps, and low-resolution optical spectra of the nearby galaxy ESO 1327-2041, which is located 38 arcsec (14 kpc in projection) west of the quasar PKS…
Supermassive binary black holes at sub-parsec orbital separations have yet to be discovered, with the possible exception of blazar OJ~287. In parallel to the global hunt for nanohertz gravitational waves from supermassive binaries using…
It is pointed out that there are now known four very close pairs of QSOs with separations < 5 arcsec and very different redshifts. Several estimates of the probability that they are accidental configurations range between 10^{-7} and 3.5 x…
We report the discovery of the correlated optical/X-ray low-frequency quasi-periodic oscillations (QPOs) in black hole binary SWIFT J1753.5-0127. The phase lag between two light-curves at the QPO frequency is close to zero. This result puts…
In cases where both components of a binary system show oscillations, asteroseismology has been proposed as a method to identify the system. For KIC 2568888, observed with $Kepler$, we detect oscillation modes for two red giants in a single…