Discovery of the optically bright, wide separation double quasar SDSS J1442+4055

TL;DR

This paper reports the discovery of a new optically bright, wide separation double quasar, SDSS J1442+4055, which is valuable for cosmological studies and monitoring active galactic nuclei.

Contribution

The paper presents the identification of a new wide separation double quasar from SDSS-III data, including analysis of its properties and potential as a gravitational lens system.

Findings

Discovered SDSS J1442+4055 as a bright, wide separation double quasar.

Identified two additional double quasar candidates with potential lensing evidence.

Demonstrated the suitability of these quasars for monitoring and cosmological measurements.

Abstract

Optically bright, wide separation double (gravitationally lensed) quasars can be easily monitored, leading to light curves of great importance in determining the Hubble constant and other cosmological parameters, as well as the structure of active nuclei and halos of galaxies. Searching for new double quasars in the SDSS-III database, we discovered SDSS J1442+4055. This consists of two bright images (18-19 magnitudes in the r band) of the same distant quasar at redshift z = 2.575. The two quasar images are separated by about 2.1 arcsec, show significant parallel flux variations and can be monitored from late 2015. We also found other two double quasar candidates, SDSS J1617+3827 (z = 2.079) and SDSS J1642+3200 (z = 2.264), displaying evidence for the presence of a lensing object and parallel flux variations, but requiring further spectroscopic observations to be confirmed as lensed quasars.