Related papers: Discovery of a 2 Kpc Binary Quasar

We report the discovery of a new gravitational lens candidate Q2138-431AB, comprising two quasar images at a redshift of 1.641 separated by 4.5 arcsecs. The spectra of the two images are very similar, and the redshifts agree to better than…

We report the discovery of the new double quasar CTQ 839. This B = 18.3, radio quiet quasar pair is separated by 2.1" in BRIH filters with magnitude differences of delta m_B = 2.5, delta m_R = delta m_I = 1.9, and delta m_H = 2.3. Spectral…

We present an investigation of the environment (\approx 600 kpc radius) of a pair of luminous z=4.25 quasars, SDSS J1439-0034 A,B, separated by 33''. An analysis of high-quality Subaru spectra of the quasars suggests that this configuration…

SDSSJ092712.65+294344.0 was identified by the SDSS as a quasar, but has the unusual property of having two emission line systems offset by 2650 km/s. One of these contains the usual combination of broad and narrow lines, the other only…

We present the discovery of a triplet of quasars at z~1.51. The whole system is well accommodated within 25 arcsec (i.e., 200 kpc in projected distance). The velocity differences among the three objects (as measured through the broad MgII…

We present the first luminous, spatially resolved binary quasar that clearly inhabits an ongoing galaxy merger. SDSS J125455.09+084653.9 and SDSS J125454.87+084652.1 (SDSS J1254+0846 hereafter) are two luminous z=0.44 radio quiet quasars,…

We report the results of an optical spectroscopic follow-up of four double quasar candidates in the Sloan Digital Sky Survey (SDSS) database. SDSS J1617+3827 is most likely a lensed quasar at z = 2.079, consisting of two images with r ~…

We report the discovery of a pair of quasars at $z=1.487$, with a separation of $8\farcs585\pm0\farcs002$. Subaru Telescope infrared imaging reveals the presence of an elliptical and a disk-like galaxy located almost symmetrically between…

We report on the discovery of a supermassive binary black hole system in the radio galaxy 0402+379, with a projected separation between the two black holes of just 7.3 pc. This is the closest black hole pair yet found by more than two…

Galaxies are believed to evolve through merging, which should lead to multiple supermassive black holes in some. There are four known triple black hole systems, with the closest pair being 2.4 kiloparsecs apart (the third component is more…

Distant quasars are unique tracers to study the formation of the earliest supermassive black holes (SMBHs) and the history of cosmic reionization. Despite extensive efforts, only two quasars have been found at $z\ge7.5$, due to a…

The z=1.377, B=17.0 mag quasar SBS 0909+532 A, B is a double with two images separated by 1.107 +/- 0.006 arcsec. Because the faint image has an emission line at the same wavelength as the MgII 2798 A emission line of the quasar, and lacks…

We report the discovery of a possible close binary system of quasars in SDSS J1048+0055. The [OIII]4959,5007 emission lines are clearly double-peaked, and two discrete radio sources with a projected physical separation of ~20 pc are found…

The strong radio source 3C343.1 consists of a galaxy and a QSO separated by no more than about 0.25 arcsec. The chance of this being an accidental superposition is conservatively 10^-8. The z=0.344 galaxy is connected to the z=0.750 QSO by…

We investigate the theoretical expectations for detections of supermassive binary black holes that can be identified as sub-parsec luminous quasars. To-date, only two candidates have been selected in a sample comprising 17,500 sources…

Close quasar pairs are rare products of galaxy mergers in which both supermassive black holes (SMBHs) are actively accreting, offering strong constraints on merger-driven active galactic nuclei (AGN) evolution. Identifying close quasar…

We report the discovery of an ultra-luminous quasar J030642.51+185315.8 (hereafter J0306+1853) at redshift 5.363, which hosts a super-massive black hole (SMBH) with $M_{BH} = (1.07 \pm 0.27) \times10^{10}~M_\odot$. With an absolute…

So far, roughly 40 quasars with redshifts greater than z=6 have been discovered. Each quasar contains a black hole with a mass of about one billion solar masses ($10^9 M_\odot$). The existence of such black holes when the Universe was less…

We present JWST observations of the environments surrounding two high-redshift quasars, J0252$-$0503 at $z = 7.0$ and J1007$+$2115 at $z = 7.5$, which enable the first constraints on quasar-galaxy clustering at $z \sim 7.3$. Galaxies in the…

Quasar pairs are either physically distinct binary quasars or the result of gravitational lensing. The majority of known pairs are in fact lenses, with a few confirmed as binaries, leaving a population of objects that have not yet been…