Related papers: Discovery of Four kpc-Scale Binary AGNs

According to hierarchical structure formation models, merging galaxies are expected to be seen in different stages of their coalescence. However, currently there are no straightforward observational methods neither to select nor to confirm…

Some Type-1 active galactic nuclei (AGNs) are showing extremely asymmetric Balmer lines with the broad peak redshifted or blueshifted by thousands of km/s. These AGNs may be good candidates for supermassive binary black holes (SMBBHs). The…

The conditions under which binary black hole (BBH) mergers embedded in active galactic nucleus (AGN) disks produce detectable optical counterparts remain poorly constrained observationally. We report multi-epoch optical imaging and…

Despite the increasing number of Gravitational Wave (GW) detections, the astrophysical origin of Binary Black Hole (BBH) mergers remains elusive. A promising formation channel for BBHs is inside accretion discs around supermassive black…

Supermassive black holes (SMBHs) can be ejected from their galactic centers due to gravitational wave recoil or the slingshot mechanism following a galaxy merger. If an ejected SMBH retains its inner accretion disk, it may be visible as an…

We present a new sample of 116 double-peaked Balmer line Active Galactic Nuclei (AGN) selected from the Sloan Digital Sky Survey. Double-peaked emission lines are believed to originate in the accretion disks of AGN, a few hundred…

Binary supermassive black hole (SMBH) systems result from galaxy mergers, and will eventually coalesce due to gravitational wave (GW) emission if the binary separation can be reduced to $\lesssim 0.1$ pc by other mechanisms. Here, we…

We study the fraction of dual AGN in a sample of 167 nearby (z<0.05), moderate luminosity, ultra hard X-ray selected AGN from the all-sky Swift BAT survey. Combining new Chandra and Gemini observations together with optical and X-ray…

We present analysis of Chandra X-ray observations of seven quasars that were identified as candidate sub-parsec binary supermassive black hole (SMBH) systems in the Catalina Real-Time Transient Survey (CRTS) based on apparent periodicity in…

We present a sample of 131 quasars from the Sloan Digital Sky Survey at redshifts 0.8<z<1.6 with double peaks in either of the high-ionization narrow emission lines [NeV]3426 or [NeIII]3869. These sources were selected with the intention of…

We present a large sample of eclipsing binary stars detected in the Small Magellanic Cloud fields covering about 14 square degrees that have been monitored for eight years during the third phase of the OGLE survey. This is the largest set…

We report the discovery of a kiloparsec-scale dual active galactic nucleus (AGN) in J0038+4128. From the Hubble Space Telescope (HST) Wide Field Planetary Camera (WFPC2) images, we find two optical nuclei with a projection separation of 4.7…

Mrk\,622 is a Compton Thick AGN and a double-peaked narrow emission line galaxy, thus a dual AGN candidate. In this work, new optical long-slit spectroscopic observations clearly show that this object is rather a triple peaked narrow…

Merger simulations predict that tidally induced gas inflows can trigger kpc-scale dual active galactic nuclei (dAGN) in heavily obscured environments. Previously with the Very Large Array, we have confirmed four dAGN with redshifts between…

We present a sample of 18 optically-selected and X-ray detected spatially offset active galactic nuclei (AGN) from the Sloan Digital Sky Survey (SDSS). In 9 systems, the X-ray AGN is spatially offset from the galactic stellar core that is…

Dual Active Galactic Nuclei (dual AGNs), a phase in some galaxy mergers during which both central supermassive black holes (SMBHs) are active, are expected to be a key observable stage leading up to SMBH mergers. Constraining the population…

Massive black-hole (MBH) binaries, which are expected to form following the merger of their parent galaxies, produce gravitational waves which will be detectable by Pulsar Timing Arrays at nanohertz frequencies (year periods). While no…

We present optical observations of two remarkable new AGN discovered by the Two-Micron All Sky Survey. Both are classified as QSOs based on their optical spectra, near-IR colors, and near-IR and [O III]5007 luminosities, but their optical…

Galaxy mergers produce pairs of supermassive black holes (SMBHs), which may be witnessed as dual quasars if both SMBHs are rapidly accreting. The kiloparsec (kpc)-scale separation represents a physical regime sufficiently close for…

We present strong evidence for dual active galactic nuclei (AGN) in the z=0.36 galaxy COSMOS J100043.15+020637.2. COSMOS Hubble Space Telescope (HST) imaging of the galaxy shows a tidal tail, indicating that the galaxy recently underwent a…