We present a comprehensive analysis of the extended emission line region (EELR) in the host galaxy of the tidal disruption event (TDE) AT2019qiz, utilizing VLT/MUSE integral-field spectroscopy. The high spatial-resolution data reveal a bi-conical emission structure approximately $3.7~\mathrm{ kpc}$ in scale within the galactic center, characterized by a prominent [OIII] line in the nucleus and significant [NII] line emission extending into the EELR. Spectral analysis of the EELR indicates line ratios consistent with Seyfert ionization in the center and LINER-type ionization in the outer diffuse region, suggesting ionization from galactic nuclear activity. The required ionizing luminosity, estimated from the H$\rm{ \alpha}$ and H$\rm{ \beta}$ luminosities based on the photoionization and recombination balance assumption, is $10^{ 41.8}$ $\mathrm{ erg\,s^{ -1}}$ for all spaxels classified as active galactic nucleus (AGN), and $10^{ 40.7}$ $\mathrm{ erg\,s^{ -1}}$ for spaxels in the central $0.9~\mathrm{ kpc}$ Seyfert region. However, the current bolometric luminosity of the nucleus $L_{ \text{ bol}} \leq 10^{ 40.8}\,\mathrm{ erg\,s^{ -1}}$, estimated from quiescent-state soft X-ray observations, is insufficient to ionize the entire EELR, implying a recently faded AGN or a delayed response to historical activity. Stellar population analysis reveals a post-starburst characteristic in the EELR, and the gas kinematics show disturbances and non-circular components compared to the stellar kinematics. Notably, the recent detection of quasi-periodic eruptions (QPEs) in the X-ray light curve of AT2019qiz confirms the TDE-QPE association. Our findings provide direct evidence for an AGN-like EELR in the host galaxy of the nearest TDE with QPE detection, offering new insights into the complex interplay between TDEs, QPEs, AGN activity, and host galaxy evolution.
Categories: astro-ph.GA astro-ph.HE