English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We present a pan-chromatic study of AT2017bcc, a nuclear transient that wasdiscovered in 2017 within the skymap of a reported burst-like gravitationalwave candidate, G274296. It was initially classified as a superluminoussupernova, and then reclassified as a candidate tidal disruption event. Itsoptical light curve has since shown ongoing variability with a structurefunction consistent with that of an active galactic nucleus, however earlierdata shows no variability for at least 10 years prior to the outburst in 2017.The spectrum shows complex profiles in the broad Balmer lines: a centralcomponent with a broad blue wing, and a boxy component with time-variable blueand red shoulders. The H$\alpha$ emission profile is well modelled using acircular accretion disc component, and a blue-shifted double Gaussian which mayindicate a partially obscured outflow. Weak narrow lines, together with thepreviously flat light curve, suggest that this object represents a dormantgalactic nucleus which has recently been re-activated. Our time-seriesmodelling of the Balmer lines suggests that this is connected to a disturbancein the disc morphology, and we speculate this could involve a sudden violentevent such as a tidal disruption event involving the central supermassive blackhole. Although we find that the redshifts of AT2017bcc ($z=0.13$) and G274296($z>0.42$) are inconsistent, this event adds to the growing diversity of bothnuclear transients and multi-messenger contaminants.

Time-varying double-peaked emission lines following the sudden ignition of the dormant galactic nucleus AT2017bcc