Title: MUSE Reveals a Recent Merger in the Post-Starburst Host Galaxy of the TDE ASASSN-14li

Abstract

We introduce Multi Unit Spectroscopic Explorer (MUSE) integral field spectroscopic observations of the host galaxy (PGC 043234) of one of the closest (z = 0.0206, D ≃ 90 Mpc) and best-studied tidal disruption events (TDEs), ASASSN-14li. The MUSE integral field data reflect asymmetric and filamentary structures that extend up to ≳10 kpc from the post-starburst host galaxy of ASASSN-14li. The structures are traced only through the strong nebular [O III] λ5007, [N II] λ6584, and Hα emission lines. The total off-nuclear [O III] λ5007 luminosity is 4.7 × 1039 erg s^-1, and the ionized H mass is $$\sim {10}^{4}(500/{n}_{{\rm{e}}})\,{M}_{\odot }$$. Based on the Baldwin–Phillips–Terlevich 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.

Authors:

Prieto, J. L.  ^[1];

• Search DOE PAGES for author "Prieto, J. L."
• Search DOE PAGES for ORCID "0000-0003-0943-0026"

Krühler, T.  ^[2];

• Search DOE PAGES for author "Krühler, T."
• Search DOE PAGES for ORCID "0000-0002-8682-2384"

Anderson, J. P.  ^[3];

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• Search DOE PAGES for ORCID "0000-0003-0227-3451"

Galbany, L.  ^[4];

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• Search DOE PAGES for ORCID "0000-0002-1296-6887"

Kochanek, C. S.  ^[5];

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• Search DOE PAGES for ORCID "0000-0001-6017-2961"

Aquino, E.  ^[6];

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• Search DOE PAGES for ORCID "0000-0003-1083-9208"

Brown, J. S.  ^[5];

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• Search DOE PAGES for ORCID "0000-0002-1885-6419"

Dong, Subo  ^[7];

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• Search DOE PAGES for ORCID "0000-0002-1027-0990"

Förster, F.  ^[4];

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Holoien, T. W. -S.  ^[5];

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• Search DOE PAGES for ORCID "0000-0001-9206-3460"

Kuncarayakti, H.  ^[4];

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• Search DOE PAGES for ORCID "0000-0002-1132-1366"

Maureira, J. C.  ^[8];

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• Search DOE PAGES for ORCID "0000-0002-7458-6142"

Rosales-Ortega, F. F.  ^[9];

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• Search DOE PAGES for ORCID "0000-0002-3642-9146"

Sánchez, S. F.  ^[6];

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• Search DOE PAGES for ORCID "0000-0001-6444-9307"

Shappee, B. J.  ^[10];

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• Search DOE PAGES for ORCID "0000-0003-4631-1149"

Stanek, K. Z. ^[5]

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+ Show Author Affiliations

1. Diego Portales Univ. (Chile); Millennium Inst. of Astrophysics, Santiago (Chile)
2. Max-Planck-Institut für Extraterrestrische Physik (MPE), Garching (Germany)
3. European Southern Observatory, Santiago (Chile)
4. Millennium Inst. of Astrophysics, Santiago (Chile); Univ. of Chile, Santiago (Chile)
5. The Ohio State Univ., Columbus, OH (United States)
6. Univ. Nacional Autonoma de Mexico (UNAM), Mexico City (Mexico)
7. Peking Univ., Beijing (China)
8. Univ. of Chile, Santiago (Chile)
9. National Inst. of Astrophysics, Optics and Electronics, Puebla (México)
10. Carnegie Observatories, Pasadena, CA (United States)

Publication Date:

Tue Oct 18 00:00:00 EDT 2016

Research Org.:

Krell Institute, Ames, IA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR)

OSTI Identifier:

1537194

Grant/Contract Number:  

FG02-97ER25308

Resource Type:

Accepted Manuscript

Journal Name:

The Astrophysical Journal. Letters (Online)

Additional Journal Information:

Journal Name: The Astrophysical Journal. Letters (Online); Journal Volume: 830; Journal Issue: 2; Journal ID: ISSN 2041-8213

Publisher:

Institute of Physics (IOP)

Country of Publication:

United States

Language:

English

Subject:

79 ASTRONOMY AND ASTROPHYSICS; accretion, accretion disks; black hole physics; galaxies: active; galaxies: evolution; galaxies: interactions