TY - JOUR
T1 - Delayed appearance and evolution of coronal lines in the TDE AT2019qiz
AU - Short, P.
AU - Lawrence, A.
AU - Nicholl, M.
AU - Ward, M.
AU - Reynolds, T. M.
AU - Mattila, S.
AU - Yin, C.
AU - Arcavi, I
AU - Carnall, A.
AU - Charalampopoulos, P.
AU - Gromadzki, M.
AU - Jonker, P. G.
AU - Kim, S.
AU - Leloudas, G.
AU - Mandel, I
AU - Onori, F.
AU - Pursiainen, M.
AU - Schulze, S.
AU - Villforth, C.
AU - Wevers, T.
PY - 2023
Y1 - 2023
N2 - 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.
AB - 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.
KW - Accretion
KW - Accretion discs
KW - Black hole physics
KW - Transients: tidal disruption events
U2 - 10.1093/mnras/stad2270
DO - 10.1093/mnras/stad2270
M3 - Journal article
SN - 0035-8711
VL - 525
SP - 1568
EP - 1587
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 1
ER -