Quasars physical properties study based on the medium-band photometric survey

TL;DR

This study analyzes the cosmological evolution of quasars using medium-band photometric data combined with multi-wavelength surveys, resulting in a large quasar sample and insights into their space density across redshifts.

Contribution

It introduces a comprehensive method for classifying quasars and determining their properties using medium-band photometry integrated with multiple survey data, expanding the understanding of quasar evolution.

Findings

Compiled a sample of 682 quasars with photometric redshifts.

Calculated quasar space density across different luminosities and redshifts.

Compared results with previous studies to validate findings.

Abstract

The 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, infrared photometry from the WISE survey, spectroscopy from the SDSS survey, ROSAT X-ray data, FIRST radio data and stellar parallax data from the GAIA survey. 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 $\lambda$-CDM model with $\Omega_m = 0.3$ and $\Omega_\lambda = 0.7$. In this paper, we present the comparison of our results with other works.