Long-term NIR Variability in the UKIDSS Ultra Deep Survey: a new probe of AGN activity at high redshift

E. Elmer, O. Almaini, M. Merrifield, W. G. Hartley, D. T. Maltby, A. Lawrence, I. Botti, P. Hirst

Research output: Contribution to journalArticlepeer-review

Abstract

We present the first attempt to select AGN using long-term NIR variability. By analysing the K-band light curves of all the galaxies in the UKIDSS Ultra Deep Survey, the deepest NIR survey over ~1 sq degree, we have isolated 393 variable AGN candidates. A comparison to other selection techniques shows that only half of the variable sources are also selected using either deep Chandra X-ray imaging or IRAC colour selection, suggesting that using NIR variability can locate AGN that are missed by more standard selection techniques. In particular, we find that long-term NIR variability identifies AGN at low luminosities and in host galaxies with low stellar masses, many of which appear relatively X-ray quiet.
Original languageEnglish
Pages (from-to)3026-3035
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Volume493
Issue number2
Early online date11 Feb 2020
DOIs
Publication statusPublished - 1 Apr 2020

Keywords

  • astro-ph.GA

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