Extending the variability selection of active galactic nuclei in the W-CDF-S and SERVS/SWIRE region
Abstract
Context. 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.
Aims: We present our analysis of AGN variability in the second half of the VST survey of the Wide Chandra Deep Field South, 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.
Methods: 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.
Results: 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 ≲20% and a completeness ∼38% with respect to mid-infrared selected samples.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- February 2020
- DOI:
- 10.1051/0004-6361/201937108
- arXiv:
- arXiv:2001.02560
- Bibcode:
- 2020A&A...634A..50P
- Keywords:
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- galaxies: active;
- infrared: galaxies;
- surveys;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- A&