Discovery of Four Gravitationally Lensed Quasars from the Sloan Digital Sky Survey

TL;DR

This paper reports the discovery of four new gravitationally lensed quasars from the Sloan Digital Sky Survey, supported by follow-up imaging and spectroscopy, revealing details about their lensing properties and potential complexities.

Contribution

First identification of four gravitationally lensed quasars from SDSS with detailed follow-up observations and analysis of their lensing characteristics.

Findings

Four new lensed quasars discovered with specific image separations.

Differential reddening observed in one system's images.

Potential complexity in lensing galaxy environment for one system.

Abstract

We present the discovery of four gravitationally lensed quasars selected from the spectroscopic quasar catalog of the Sloan Digital Sky Survey. We describe imaging and spectroscopic follow-up observations that support the lensing interpretation of the following four quasars: SDSS J0832+0404 (image separation \theta=1.98", source redshift z_s=1.115, lens redshift z_l=0.659); SDSS J1216+3529 (\theta=1.49", z_s=2.012); SDSS J1322+1052 (\theta=2.00", z_s=1.716); and SDSS J1524+4409 (\theta=1.67", z_s=1.210, z_l=0.320). Each system has two lensed images. We find that the fainter image component of SDSS J0832+0404 is significantly redder than the brighter component, perhaps because of differential reddening by the lensing galaxy. The lens potential of SDSS J1216+3529 might be complicated by the presence of a secondary galaxy near the main lensing galaxy.