We report on the discovery and follow-up of a peculiar transient, OGLE17aaj, which occurred in the nucleus of a weakly active galaxy. We investigate whether it can be interpreted as a new candidate for a tidal disruption event (TDE). We present the OGLE-IV light curve that covers the slow 60-day-long rise to maximum along with photometric, spectroscopic, and X-ray follow-up during the first year. OGLE17aaj is a nuclear transient exhibiting some properties similar to previously found TDEs, including a long rise time, lack of colour-temperature evolution, and high black-body temperature. On the other hand, its narrow emission lines and slow post-peak evolution are different from previously observed TDEs. Its spectrum and light-curve evolution is similar to F01004-2237 and AT 2017bgt. Signatures of historical low-level nuclear variability suggest that OGLE17aaj may instead be related to a new type of accretion event in active super-massive black holes.
@article{arxiv.1901.03718,
title = {Discovery and Follow-up of the Unusual Nuclear Transient OGLE17aaj},
author = {M. Gromadzki and A. Hamanowicz and L. Wyrzykowski and K. V. Sokolovsky and M. Fraser and Sz. Kozlowski and J. Guillochon and I. Arcavi and B. Trakhtenbrot and P. G. Jonker and S. Mattila and A. Udalski and M. K. Szymanski and I. Soszynski and R. Poleski and P. Pietrukowicz and J. Skowron and P. Mroz and K. Ulaczyk and M. Pawlak and K. A. Rybicki and J. Sollerman and F. Taddia and Z. Kostrzewa-Rutkowska and F. Onori and D. R. Young and K. Maguire and S. J. Smartt and C. Inserra and A. Gal-Yam and A. Rau and T. -W. Chen and C. R. Angus and D. A. H. Buckley},
journal= {arXiv preprint arXiv:1901.03718},
year = {2019}
}
Comments
5 pages, 3 figures, accepted for publication in Astronomy & Astrophysics as Letter to Editor