Quasars' physical properties study based on the medium‐band photometric survey

Abstract

AbstractThe study is about the quasars' cosmological evolution. We used the medium‐band photometric survey at the 1‐m Schmidt telescope of the Byurakan Astrophysical Observatory. The HS47‐22 field with an area of 2.38 square degrees has been selected. We have classified objects and composed a sample of quasars using broadband photometric data and morphological classification from the DECaLS survey (Dey et al. 2019), infrared photometry from the WISE survey (Meisner et al. 2018), spectroscopy from the Sloan Digital Sky Survey (Pâris et al. 2018), ROSAT X‐ray data (Molthagen et al. 1997), FIRST radio data (Becker et al. 1995), and stellar parallax data from the GAIA survey (Gaia Collaboration et al. 2018). We have compiled a sample of 682 quasars, determined their photometric redshifts from the medium‐band photometric data, and calculated the absolute stellar magnitudes. The space density of quasars was calculated for different luminosity ranges at different redshifts using the λ‐CDM model with and (Hogg 1999). In this paper, we present the comparison of our results with other works.