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We present an $r$--band photometric monitoring of the two images A and B ofthe gravitationally lensed quasar SDSS J1442+4055 using the Liverpool Telescope(LT). From the LT light curves between 2015 December and 2018 August, we deriveat once a time delay of 25.0 $\pm$ 1.5 days (1$\sigma$ confidence interval; Ais leading) and microlensing magnification gradients below 10$^{-4}$ magday$^{-1}$. The delay interval is not expected to be affected by an appreciablemicrolensing--induced bias, so it can be used to estimate cosmologicalparameters. This paper also focuses on new Gran Telescopio Canarias (GTC) andLT spectroscopic observations of the lens system. We determine the redshift oftwo bright galaxies around the doubly imaged quasar using LT spectroscopy,while GTC data lead to low--noise individual spectra of A, B, and the mainlensing galaxy G1. The G1 spectral shape is accurately matched to anearly--type galaxy template at $z$ = 0.284, and it has potential for furtherrelevant studies. Additionally, the quasar spectra show absorption bymetal--rich gas at $z \sim$ 2. This dusty absorber is responsible for anextinction bump at a rest--frame wavelength of 2209 $\pm$ 2 \AA, which hasstrengths of $\sim$ 0.47 and 0.76 mag $\mu$m$^{-1}$ for A and B, respectively.In such intervening system, the dust--to--gas ratio, gas--phase metallicityindicator [Zn/H], and dust depletion level [Fe/Zn] are relatively high.

astrophysical journal/the astrophysical journal

Gravitationally Lensed Quasar SDSS J1442+4055: Redshifts of Lensing  Galaxies, Time Delay, Microlensing Variability, and Intervening Metal System  at z ~ 2