We present MUSE integral field spectroscopic observations of the host galaxy ( PGC 043234 ) of one of the closest ( z = 0.0206 , D \simeq 90 Mpc ) and best-studied tidal disruption events ( TDE ) , ASASSN-14li .
The MUSE integral field data reveal asymmetric and filamentary structures that extend up to \gtrsim 10 kpc from the post-starburst host galaxy of ASASSN-14li .
The structures are traced only through the strong nebular [ O iii ] \lambda 5007 , [ N ii ] \lambda 6584 , and H \alpha emission lines .
The total off nuclear [ O iii ] \lambda 5007 luminosity is 4.7 \times 10 ^ { 39 } erg s ^ { -1 } and the ionized H mass is \sim 10 ^ { 4 } ( 500 / n _ { e } ) M _ { \odot } .
Based on the BPT diagram , the nebular emission can be driven by either AGN photoionization or shock excitation , with AGN photoionization favored given the narrow intrinsic line widths .
The emission line ratios and spatial distribution strongly resemble ionization nebulae around fading AGNs such as IC 2497 ( Hanny ’ s Voorwerp ) and ionization “ cones ” around Seyfert 2 nuclei .
The morphology of the emission line filaments strongly suggest that PGC 043234 is a recent merger , which likely triggered a strong starburst and AGN activity leading to the post-starburst spectral signatures and the extended nebular emission line features we see today .
We briefly discuss the implications of these observations in the context of the strongly enhanced TDE rates observed in post-starburst galaxies and their connection to enhanced theoretical TDE rates produced by supermassive black-hole binaries .