Discovery and follow-up of the unusual nuclear transient OGLE17aaj
: Gromadzki M, Hamanowicz A, Wyrzykowski L, Sokolovsky KV, Fraser M, Kozlowski S, Guillochon J, Arcavi I, Trakhtenbrot B, Jonker PG, Mattila S, Udalski A, Szymanski MK, Soszynski I, Poleski R, Pietrukowicz P, Skowron J, Mroz P, Ulaczyk K, Pawlak M, Rybicki KA, Sollerman J, Taddia F, Kostrzewa-Rutkowska Z, Onori F, Young DR, Maguire K, Smartt SJ, Inserra C, Gal-Yam A, Rau A, Chen TW, Angus CR, Buckley DAH, Buckley DAH
Publisher: EDP SCIENCES S A
: 2019
: Astronomy and Astrophysics
: ASTRONOMY & ASTROPHYSICS
: ASTRON ASTROPHYS
: ARTN L2
: 622
: 5
: 1432-0746
: 1432-0746
DOI: https://doi.org/10.1051/0004-6361/201833682
: https://research.utu.fi/converis/portal/detail/Publication/39595853
Aims
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).
Methods
We present the OGLE-IV light curve that covers the slow 60-day-long rise to maximum along with photometric, spectro-scopic, and X-ray follow-up during the first year.
Results
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.
