THE TDE ASASSN-14li AND ITS HOST RESOLVED AT PARSEC SCALES WITH THE EVN
- Millennium Institute of Astrophysics (Chile)
- Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, 7820436 Santiago (Chile)
- Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States)
- Kavli Institute for Astronomy and Astrophysics, Peking University, Yiheyuan Road 5, Haidian District, Beijing 100871 (China)
- Department of Astronomy, Peking University, Yiheyuan Road 5, Haidian District, Beijing 100871 (China)
We report European Very Long Baseline Interferometry Network (EVN) radio continuum observations of ASASSN-14li, one of the best studied tidal disruption events (TDEs) to date. At 1.7 GHz with ≃12 × 6 mas resolution, the emission is unresolved. At 5.0 GHz with ≃3 × 2 mas resolution, the radio emission shows an extended structure that can be modeled with two components: a core-like component and a fainter, possibly elongated source 4.3 mas (∼2 pc) away. Our observations are not conclusive as to the nature of the components, but three scenarios are discussed. One possibility is a core-jet/outflow morphology, thus making of ASASSN-14li the first TDE jet/outflow directly imaged. For this case, the projected separation between the two components can only be explained by superluminal motion, rather than the lower velocities inferred from low-resolution radio observations. However, typical fast moving jets have brightness temperatures ∼5 orders of magnitude higher than we find, thus making this scenario less likely. The second possibility is that we are imaging a non-relativistic jet from past AGN/TDE activity. In this case a past TDE is preferred given that the spatial extension and radio luminosity of the elongated component are consistent with the theoretical predictions for a TDE outflow. Alternatively, the two sources could indicate the presence of a binary black hole, which would then naturally explain the enhanced TDE rates of post-starburst galaxies. Future EVN observations will help us to distinguish between these scenarios.
- OSTI ID:
- 22654154
- Journal Information:
- Astrophysical Journal Letters, Vol. 832, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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