The Close AGN Reference Survey: Mrk 1018 returns to
the shadows after 30 years as a Seyfert 1
by Rebecca McElroy (Sydney Uni)
Abstract. We report the discovery of
an AGN that has changed spectral type not once, but twice. So called `changing
look' AGN are an uncommon phenomenon, but twice changed AGN are much rarer.
This AGN first transitioned from a narrow line AGN (type 2) to a broad line
AGN (type 1) in the 1980s. It was recently observed as part of The Close AGN
Reference Survey (CARS). CARS aims to provide a detailed multi-wavelength view
of 40 nearby (0.01 < z < 0.06) unobscured AGN to study the link between AGN
and their host galaxies. The primary CARS observations come from the MUSE
integral field unit on the VLT, and complementary multi-wavelength observations
have been approved from a wide array of sources (SOFIA, Chandra, VLA, HST, and
others). Examination of the MUSE data for this particular source showed that
it no longer had the spectral features typical of a type 1 AGN. The continuum
emission from the accretion disk was no longer visible and the broad lines
were dramatically diminished. In this talk we describe the possible reasons
for this change, supported by analysis of multi-epoch optical photometry and
spectroscopy, alongside data obtained through director's discretionary time
from Chandra, HST, and the VLA. We then conclude by discussing the implications
of this discovery on our understanding of AGN timescales and the physics behind
AGN spectral types.