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Oxford University Press, Monthly Notices of the Royal Astronomical Society, 2(503), p. 2583-2597, 2021

DOI: 10.1093/mnras/stab393

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A systematic survey for z< 0.04 CLAGNs

This paper was not found in any repository, but could be made available legally by the author.
This paper was not found in any repository, but could be made available legally by the author.

Full text: Unavailable

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Preprint: archiving allowed
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Postprint: archiving allowed
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Published version: archiving allowed
Data provided by SHERPA/RoMEO

Abstract

ABSTRACT We have conducted a systematic survey for z < 0.04 active Galactic nuclei (AGNs) that may have changed spectral class over the past decade. We use SkyMapper, Pan-STARRS and the Véron-Cetty & Véron catalogue to search the entire sky for these ‘changing-look’ AGNs (CLAGNs) using a variety of selection methods, where Pan-STARRS has a coverage of 3$π$ steradians (sky north of Declination −30○) and SkyMapper has coverage of ∼21000 $~\rm {deg^2}$ (sky south of Declination 0○). We use small aperture photometry to measure how colour and flux have changed over time, where a change may indicate a change in spectral type. Optical colour and flux are used as a proxy for changing Hα equivalent width, while WISE 3.4 μm flux is used to look for changes in the hot dust component. We have identified four AGNs with varying spectra selected using our optical colour selection method. Three AGNs were confirmed from recent observations with WiFeS on the 2.3 m telescope at Siding Spring and the other was identified from archival spectra alone. From this, we identify two new CLAGNs; NGC 1346 and 2MASX J20075129–1108346. We also recover Mrk 915 and Mrk 609, which are known to have varying spectra in the literature, but they do not meet our specific criteria for CLAGNs.