During April 2013, a dramatic outburst was discovered at the core of NGC 2617,[13] and the spectral type was found to have changed to a Seyfert 1. An increase in X-ray emission was observed, followed by an increase inultraviolet and theninfraredluminosity.[4] This event can be modeled by X-ray radiation heating theaccretion disk orbiting asupermassive black hole (SMBH) at the center of the galaxy. This was followed by emission at longer wavelengths from the heated disk.[4] An increase in luminosity between 2010 and 2012 may have cleared away dust in the inner part of the disk prior to the outburst, allowing a clearer view and changing the Seyfert type of the galaxy.[14] The SMBH has an estimated mass of30.9+11.8 −8.5 million M☉.[3]
Additional outbursts were observed from 2016 to 2018, in between deep minima.[15]
^Sulentic, Jack W.; et al. (1973),The Revised New Catalogue of Nonstellar Astronomical Objects, Tucson: University of Arizona Press,Bibcode:1973rncn.book.....S.
^Boller, Th.; et al. (July 1992), "ROSAT all sky survey observations of IRAS galaxies.",Astronomy and Astrophysics,261:57–77,Bibcode:1992A&A...261...57B.
^Moran, Edward C.; et al. (October 1996), "Classification of IRAS-selected X-Ray Galaxies in the ROSAT All-Sky Survey",Astrophysical Journal Supplement,106: 341,Bibcode:1996ApJS..106..341M,doi:10.1086/192341.
^Shappee, B. J.; et al. (April 2013), "ASAS-SN Discovery of a Strong AGN Outburst and Dramatic Seyfert Type Change in NGC 2617",The Astronomer's Telegram,5010: 1,Bibcode:2013ATel.5010....1S.
^Oknyansky, V.; et al. (June 2018), "NGC 2617 brightens again after long very low state",The Astronomer's Telegram,11703: 1,Bibcode:2018ATel11703....1O.
