Mapping optically variable quasars towards the galactic plane

TL;DR

This study develops a method to identify quasar candidates near the Galactic plane using optical variability data from the CIDA Equatorial Variability Survey, analyzing a small region to demonstrate its effectiveness amid dense stellar fields.

Contribution

The paper introduces a novel approach combining variability indices and structure function analysis to select quasar candidates in crowded Galactic plane regions.

Findings

288 QSO candidates identified in 2.5 sq. deg.

Method demonstrates potential for QSO detection in dense stellar fields.

First attempt to develop robust QSO detection near the Galactic plane.

Abstract

We present preliminary results of the CIDA Equatorial Variability Survey (CEVS), looking for quasar (hereafter QSO) candidates near the Galactic plane. The CEVS contains photometric data from extended and adjacent regions of the Milky Way disk ($\sim$ 500 sq. deg.). In this work 2.5 square degrees with moderately high temporal sampling in the CEVS were analyzed. The selection of QSO candidates was based on the study of intrinsic optical photometric variability of 14,719 light curves. We studied samples defined by cuts in the variability index (Vindex $>$ 66.5), periodicity index (Q $>$ 2), and the distribution of these sources in the plane (AT , ${\gamma}$), using a slight modification of the first-order of the structure function for the temporal sampling of the survey. Finally, 288 sources were selected as QSO candidates. The results shown in this work are a first attempt to develop a robust method to detect QSO towards the Galactic plane in the era of massive surveys such as VISTA and Gaia.