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arXiv · 2610.30816

A recurring changing state AGN discovered in the SAMI Galaxy Survey and SDSS

Scott M. Croom·Rebecca McElroy·Dougal Dobie·Thomas Dunn·Yasmeen Janschek·Tyler Klinger·Shaun Parasher·Mitchell Spanner·Oliver J. Thorp
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Abstract

We present a detailed analysis of the AGN in galaxy J085337.26+014303.6 at z=0.0582. A combination of SDSS and SAMI Galaxy Survey data shows that this object has gone through at least one full changing-look AGN cycle, from type 1.9 in 2001 to type 1 in 2015 and 2021, and then type 1.9 again in 2022. While the broad lines in this object show evidence of dust obscuration, detailed spectral analysis plus WISE photometry demonstrate that the changes in this object are related to a physical state change, not changing obscuration. In fact, the WISE light curve suggests that this object may have briefly returned to a type 1.9 state in 2020. In the optical, the host galaxy dominates the light (e.g. only ~10 per cent contribution from the AGN at 4000 Angstoms within a central aperture), even in the high state. In contrast, the brightest WISE W2-band measurements place the AGN at a similar luminosity to the entire host galaxy. The broad Balmer lines show evidence of multiple components, with a weak very-broad component (FWHM=5000-6000 km/s) visible in the low type 1.9 state, and a stronger broad component of FWHM~2000 km/s dominating in the high type 1 state. We propose that this is caused by two spatially distinct regions within the broad line region.

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Scott M. Croom, Rebecca McElroy, Dougal Dobie, Thomas Dunn, Yasmeen Janschek, Tyler Klinger, Shaun Parasher, Mitchell Spanner, Oliver J. Thorp. 2026-10-22. A recurring changing state AGN discovered in the SAMI Galaxy Survey and SDSS. https://arxiv.org/abs/2610.30816

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