Exploiting the IRT-THESEUS Capability to Observe Lensed Quasars

• Published in: Galaxies 2021-06, Vol.9 (2), p.35
• Main Authors: Hamolli, Lindita, Hafizi, Mimoza, De Paolis, Francesco, Nucita, Achille A.
• Format: Article
• Language: English
• Subjects: Astronomical models; Distribution functions; Galaxies; Galaxy distribution; Gamma ray bursts; Gamma rays; gravitational lensing; Imaging spectrometers; Information sources; infrared observation; Infrared spectrometers; Infrared telescopes; Light; Luminosity; Mass distribution; Monte Carlo simulation; Physical properties; Quasars; Red shift; Sky surveys (astronomy); Soft x rays; Space telescopes; Spectrum analysis; Stars & galaxies; Universe
• ISSN: 2075-4434; 2075-4434
• DOI: 10.3390/galaxies9020035

THESEUS is an ESA space based project, which aims to explore the early universe by unveiling a complete census of Gamma-ray Burst (GRB) population in the first billion years. This goal is expected to be realized by the combined observations of its three instruments on board: the Soft X-ray Imager (SXI), the X and Gamma Imaging Spectrometer (XGIS), and the InfraRed Telescope (IRT). This last one will identify, localise, and study the afterglow of the GRBs detected by SXI and XGIS, and about 40% of its time will be devoted to an all-sky photometric survey, which will certainly detect a relevant number of extragalactic sources, including Quasars. In this paper, we focus on the capability of IRT-THESEUS Telescope to observe Quasars and, in particular, Quasars lensed by foreground galaxies. In our analysis we consider the recent results for the Quasar Luminosity Function (QLF) in the infrared band based on the Spitzer Space Telescope imaging survey. In order to estimate the number of lensed Quasars, we develop Monte Carlo simulations using the mass-luminosity distribution function of galaxies and the galaxy and Quasar redshift distributions. We predict about 2.14 × 105 Quasars to be observed during IRT-Theseus sky survey, and approximately 140 of them lensed by foreground galaxies. Detailed studies of these events would provide a powerful probe of the physical properties of Quasars and the mass distribution models of the galaxies.