AT2019aalc: An obscured tidal disruption event candidate in an active galactic nucleus revealed by its first flare?
Abstract
AT2019aalc is considered a repeating tidal disruption event (TDE) candidate occurring in an active galactic nucleus (AGN). In this paper, we highlight previously unnoticed but intriguing features that include a brief optical dimming prior to the rise of the main flare and a significantly lower post-flare luminosity compared to the pre-flare level. By applying a time-dependent obscured TDE model to AT2019aalc, we successfully reproduce its light curves with the tidal disruption of a 1.122−0.176+0.246M⊙ main-sequence star by a 1.862−0.259+0.255 × 107M⊙ supermassive black hole (SMBH). Both the pre-flare dimming and the reduced post-flare luminosity are attributed to obscuration of the intrinsic AGN emission. The total energy of the event derived from our fit is 1.24×1051 ergs and about 0.2 M⊙ of debris mass is accreted by the SMBH. In addition, the g−r color of the net flare in AT2019aalc exhibits a continuous reddening trend during the first flare, consistent with a gradual increase in E(B−V) predicted by the obscured TDE model. These results suggest that AT2019aalc can be considered a second member of the recently proposed class of obscured TDE candidates hosted in AGNs. } \keywords{galaxies: active-galaxies: nuclei-quasars: supermassive black holes-quasars: individual (AT2019aalc)-transients: tidal disruption events.
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BibTeX
@misc{gu2026at2019aalc,
title = {{AT2019aalc: An obscured tidal disruption event candidate in an active galactic nucleus revealed by its first flare?}},
author = {Ying Gu and Xiao Li and Xue-Guang Zhang and En-Wei Liang},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.24005},
eprint = {2609.24005},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.24005},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - AT2019aalc: An obscured tidal disruption event candidate in an active galactic nucleus revealed by its first flare?
AU - Ying Gu
AU - Xiao Li
AU - Xue-Guang Zhang
AU - En-Wei Liang
PY - 2026
DA - 2026/09/21
PB - arXiv
DO - 10.48550/arxiv.2609.24005
UR - https://arxiv.org/abs/2609.24005
AB - AT2019aalc is considered a repeating tidal disruption event (TDE) candidate occurring in an active galactic nucleus (AGN). In this paper, we highlight previously unnoticed but intriguing features that include a brief optical dimming prior to the rise of the main flare and a significantly lower post-flare luminosity compared to the pre-flare level. By applying a time-dependent obscured TDE model to AT2019aalc, we successfully reproduce its light curves with the tidal disruption of a 1.122_−0.176^+0.246M_⊙ main-sequence star by a 1.862_−0.259^+0.255 × 10^7M_⊙ supermassive black hole (SMBH). Both the pre-flare dimming and the reduced post-flare luminosity are attributed to obscuration of the intrinsic AGN emission. The total energy of the event derived from our fit is 1.24×10^51 ergs and about 0.2 M_⊙ of debris mass is accreted by the SMBH. In addition, the g−r color of the net flare in AT2019aalc exhibits a continuous reddening trend during the first flare, consistent with a gradual increase in E(B−V) predicted by the obscured TDE model. These results suggest that AT2019aalc can be considered a second member of the recently proposed class of obscured TDE candidates hosted in AGNs. } \keywords{galaxies: active-galaxies: nuclei-quasars: supermassive black holes-quasars: individual (AT2019aalc)-transients: tidal disruption events.
ER -