Episodic X-ray Outflows from the Tidal Disruption Event ASASSN-14li

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Hauptverfasser: Ajay, Yukta, Pasham, Dheeraj R., Wevers, Thomas, Coughlin, Eric R., Tombesi, Francesco, Guolo, Muryel, Steiner, James F.
Format: Preprint
Veröffentlicht: 2024
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author Ajay, Yukta
Pasham, Dheeraj R.
Wevers, Thomas
Coughlin, Eric R.
Tombesi, Francesco
Guolo, Muryel
Steiner, James F.
author_facet Ajay, Yukta
Pasham, Dheeraj R.
Wevers, Thomas
Coughlin, Eric R.
Tombesi, Francesco
Guolo, Muryel
Steiner, James F.
contents ASASSN-14li is a low-redshift ($z= 0.0206$) tidal disruption event (TDE) that has been studied extensively across the entire electromagnetic spectrum, and has provided one of the most sensitive measurements of a TDE to-date. Its X-ray spectrum is soft and thermal (kT$\sim$ 0.05 keV) and shows a residual broad absorption-like feature between 0.6-0.8 keV, which can be associated with a blue-shifted O VII (rest-frame energy 0.57 keV) resulting from an ultrafast outflow (UFO) at early times (within 40 days of optical discovery). By carefully accounting for pile-up and using precise XSTAR photo-ionization table models, we analyze the entire archival X-ray data from XMM-Newton and track the evolution of this absorption feature for $\sim$4.5 years post disruption. Our main finding is that, contrary to the previous literature, the absorption feature is transient and intermittent. Assuming the same underlying physical basis (i.e. outflows) for the recurring absorption feature in ASASSN-14li, the outflow is seen to disappear and reappear multiple times during the first $\sim$2 years of its evolution. No observable spectral imprint is detected thereafter. While theoretical studies suggest the launch of outflows in the early phases of the outburst during the super-Eddington regime, the outflow's intermittent behavior for multiple years after disruption is unusual. We discuss this peculiar behavior within the context of varying inner disk truncation, radiation pressure, and magnetically-driven outflow scenarios.
format Preprint
id arxiv_https___arxiv_org_abs_2401_12908
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Episodic X-ray Outflows from the Tidal Disruption Event ASASSN-14li
Ajay, Yukta
Pasham, Dheeraj R.
Wevers, Thomas
Coughlin, Eric R.
Tombesi, Francesco
Guolo, Muryel
Steiner, James F.
High Energy Astrophysical Phenomena
Astrophysics of Galaxies
ASASSN-14li is a low-redshift ($z= 0.0206$) tidal disruption event (TDE) that has been studied extensively across the entire electromagnetic spectrum, and has provided one of the most sensitive measurements of a TDE to-date. Its X-ray spectrum is soft and thermal (kT$\sim$ 0.05 keV) and shows a residual broad absorption-like feature between 0.6-0.8 keV, which can be associated with a blue-shifted O VII (rest-frame energy 0.57 keV) resulting from an ultrafast outflow (UFO) at early times (within 40 days of optical discovery). By carefully accounting for pile-up and using precise XSTAR photo-ionization table models, we analyze the entire archival X-ray data from XMM-Newton and track the evolution of this absorption feature for $\sim$4.5 years post disruption. Our main finding is that, contrary to the previous literature, the absorption feature is transient and intermittent. Assuming the same underlying physical basis (i.e. outflows) for the recurring absorption feature in ASASSN-14li, the outflow is seen to disappear and reappear multiple times during the first $\sim$2 years of its evolution. No observable spectral imprint is detected thereafter. While theoretical studies suggest the launch of outflows in the early phases of the outburst during the super-Eddington regime, the outflow's intermittent behavior for multiple years after disruption is unusual. We discuss this peculiar behavior within the context of varying inner disk truncation, radiation pressure, and magnetically-driven outflow scenarios.
title Episodic X-ray Outflows from the Tidal Disruption Event ASASSN-14li
topic High Energy Astrophysical Phenomena
Astrophysics of Galaxies
url https://arxiv.org/abs/2401.12908