Extending the variability selection of active galactic nuclei in the W-CDF-S and SERVS/SWIRE region

Abstract

Variability has proven to be a powerful tool to detect active galactic nuclei (AGN) in multi-epoch surveys. The new-generation facilities expected to become operational in the next few years will mark a new era in time-domain astronomy and their wide-field multi-epoch campaigns will favor extensive variability studies. We present our analysis of AGN variability in the second half of the VST survey of the Wide Chandra Deep Field South (W-CDF-S), performed in the r band and covering a 2 sq. deg. area. The analysis complements a previous work, in which the first half of the area was investigated. We provide a reliable catalog of variable AGN candidates, which will be critical targets in future variability studies. We selected a sample of optically variable sources and made use of infrared data from the Spitzer mission to validate their nature by means of color-based diagnostics. We obtain a sample of 782 AGN candidates among which 12 are classified as supernovae, 54 as stars, and 232 as AGN. We estimate a contamination $\lesssim 20\%$ and a completeness $\sim 38\%$ with respect to mid-infrared selected samples.

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Cited by in corpus (6)

• The XMM-SERVS survey: XMM-Newton point-source catalogs for the W-CDF-S and ELAIS-S1 fields
• A random forest-based selection of optically variable AGN in the VST-COSMOS field
• Radio AGN Selection and Characterization in Three Deep-Drilling Fields of the Vera C. Rubin Observatory Legacy Survey of Space and Time
• Selection of optically variable active galactic nuclei via a random forest algorithm
• Variability and transient search in the SUDARE-VOICE field: a new method to extract the light curves
• Properties of Polarized Radio Sources in the Wide Chandra Deep Field South from 2 to 4GHz