The spectral evolution of disc dominated tidal disruption events

We perform a detailed numerical and analytical study of the properties of observed light curves from relativistic thin discs, focussing on observational bands most appropriate for comparison with tidal disruption events (TDEs). We make use of asymptotic expansion techniques applied to the spectral e...

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Váldodahkkit: Mummery, A, Balbus, SA
Materiálatiipa: Journal article
Giella:English
Almmustuhtton: Oxford University Press 2020
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author Mummery, A
Balbus, SA
author_facet Mummery, A
Balbus, SA
author_sort Mummery, A
collection OXFORD
description We perform a detailed numerical and analytical study of the properties of observed light curves from relativistic thin discs, focussing on observational bands most appropriate for comparison with tidal disruption events (TDEs). We make use of asymptotic expansion techniques applied to the spectral emission integral, using time-dependent disc temperature profiles appropriate for solutions of the relativistic thin disc equation. Rather than a power law associated with bolometric disc emission L ∼ t−n, the observed X-ray flux from disc-dominated TDEs will typically have the form of a power law multiplied by an exponential (see equation 91). While precise details are somewhat dependent on the nature of the ISCO stress and disc-observer orientational angle, the general form of the time-dependent flux is robust and insensitive to the exact disc temperature profile. We present numerical fits to the UV and X-ray light curves of ASASSN-14li, a particularly well observed TDE. This modelling incorporates strong gravity optics. The full 900 d of ASASSN-14li X-ray observations are very well fit by a simple relativistic disc model, significantly improving upon previous work. The same underlying model also fits the final 1000 d of ASASSN-14li observations in three different UV bandpasses. Finally, we demonstrate that the analytic formulae reproduce the properties of full numerical modelling at both UV and X-ray wavelengths with great fidelity.
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spelling oxford-uuid:2f715b1b-2295-4bc3-a10c-74a24fd36b582022-03-26T12:55:27ZThe spectral evolution of disc dominated tidal disruption eventsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:2f715b1b-2295-4bc3-a10c-74a24fd36b58EnglishSymplectic ElementsOxford University Press2020Mummery, ABalbus, SAWe perform a detailed numerical and analytical study of the properties of observed light curves from relativistic thin discs, focussing on observational bands most appropriate for comparison with tidal disruption events (TDEs). We make use of asymptotic expansion techniques applied to the spectral emission integral, using time-dependent disc temperature profiles appropriate for solutions of the relativistic thin disc equation. Rather than a power law associated with bolometric disc emission L ∼ t−n, the observed X-ray flux from disc-dominated TDEs will typically have the form of a power law multiplied by an exponential (see equation 91). While precise details are somewhat dependent on the nature of the ISCO stress and disc-observer orientational angle, the general form of the time-dependent flux is robust and insensitive to the exact disc temperature profile. We present numerical fits to the UV and X-ray light curves of ASASSN-14li, a particularly well observed TDE. This modelling incorporates strong gravity optics. The full 900 d of ASASSN-14li X-ray observations are very well fit by a simple relativistic disc model, significantly improving upon previous work. The same underlying model also fits the final 1000 d of ASASSN-14li observations in three different UV bandpasses. Finally, we demonstrate that the analytic formulae reproduce the properties of full numerical modelling at both UV and X-ray wavelengths with great fidelity.
spellingShingle Mummery, A
Balbus, SA
The spectral evolution of disc dominated tidal disruption events
title The spectral evolution of disc dominated tidal disruption events
title_full The spectral evolution of disc dominated tidal disruption events
title_fullStr The spectral evolution of disc dominated tidal disruption events
title_full_unstemmed The spectral evolution of disc dominated tidal disruption events
title_short The spectral evolution of disc dominated tidal disruption events
title_sort spectral evolution of disc dominated tidal disruption events
work_keys_str_mv AT mummerya thespectralevolutionofdiscdominatedtidaldisruptionevents
AT balbussa thespectralevolutionofdiscdominatedtidaldisruptionevents
AT mummerya spectralevolutionofdiscdominatedtidaldisruptionevents
AT balbussa spectralevolutionofdiscdominatedtidaldisruptionevents