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Delayed appearance and evolution of coronal lines in the TDE AT2019qiz

Short, P; Lawrence, A; Nicholl, M; Ward, M; Reynolds, T M; Mattila, S; Yin, C; Arcavi, I; Carnall, A; Charalampopoulos, P; Gromadzki, M; Jonker, P G; Kim, S; Leloudas, G; Mandel, I; Onori, F; Pursiainen, M; Schulze, S; Villforth, C; Wevers, T

Delayed appearance and evolution of coronal lines in the TDE AT2019qiz Thumbnail


P Short

A Lawrence

M Nicholl

T M Reynolds

S Mattila

C Yin

I Arcavi

A Carnall

P Charalampopoulos

M Gromadzki

P G Jonker

S Kim

G Leloudas

I Mandel

F Onori

M Pursiainen

S Schulze

C Villforth

T Wevers


Tidal disruption events (TDEs) occur when a star gets torn apart by a supermassive black hole as it crosses its tidal radius. We present late-time optical and X-ray observations of the nuclear transient AT2019qiz, which showed the typical signs of an optical-UV transient class commonly believed to be TDEs. Optical spectra were obtained 428, 481, and 828 rest-frame days after optical light-curve peak, and a UV/X-ray observation coincided with the later spectrum. The optical spectra show strong coronal emission lines, including [Fe VII], [Fe X], [Fe XI], and [Fe XIV]. The Fe lines rise and then fall, except [Fe XIV] that appears late and rises. We observe increasing flux of narrow H α and H β and a decrease in broad H α flux. The coronal lines have full width at half-maximum ranging from ∼150−300 km s−1, suggesting they originate from a region between the broad- and narrow-line emitting gas. Between the optical flare and late-time observation, the X-ray spectrum softens dramatically. The 0.3–1 keV X-ray flux increases by a factor of ∼50, while the hard X-ray flux decreases by a factor of ∼6. Wide-field Infrared Survey Explorer fluxes also rose over the same period, indicating the presence of an infrared echo. With AT2017gge, AT2019qiz is one of two examples of a spectroscopically confirmed optical-UV TDE showing delayed coronal line emission, supporting speculations that Extreme Coronal Line Emitters in quiescent galaxies can be echos of unobserved past TDEs. We argue that the coronal lines, narrow lines, and infrared emission arise from the illumination of pre-existing material likely related to either a previous TDE or active galactic nucleus activity.


Short, P., Lawrence, A., Nicholl, M., Ward, M., Reynolds, T. M., Mattila, S., …Wevers, T. (2023). Delayed appearance and evolution of coronal lines in the TDE AT2019qiz. Monthly Notices of the Royal Astronomical Society, 525(1), 1568-1587.

Journal Article Type Article
Acceptance Date Jul 18, 2023
Online Publication Date Jul 26, 2023
Publication Date 2023-10
Deposit Date Jan 25, 2024
Publicly Available Date Jan 25, 2024
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 525
Issue 1
Pages 1568-1587
Public URL


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