An Energy Inventory of Tidal Disruption Events. (arXiv:2007.12198v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Mockler_B/0/1/0/all/0/1">Brenna Mockler</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ramirez_Ruiz_E/0/1/0/all/0/1">Enrico Ramirez-Ruiz</a>
Tidal disruption events (TDEs) offer a unique opportunity to study a single
super-massive black hole (SMBH) under feeding conditions that change over
timescales of days or months. However, the primary mechanism for generating
luminosity during the flares remains debated. Despite the increasing number of
observed TDEs, it is unclear whether most of the energy in the initial flare
comes from accretion near the gravitational radius or from circularizing debris
at larger distances from the SMBH. The energy dissipation efficiency increases
with decreasing radii, therefore by measuring the total energy emitted and
estimating the efficiency we can derive clues about the nature of the emission
mechanism. Here we calculate the integrated energy, emission timescales, and
average efficiencies for the TDEs using the Modular Open Source Fitter for
Transients ({tt MOSFiT}). Our calculations of the total energy generally yield
higher values than previous estimates. This is predominantly because, if the
luminosity follows the mass fallback rate, TDEs release a significant fraction
of their energy long after their light curve peaks. We use {tt MOSFiT} to
calculate the conversion efficiency from mass to radiated energy, and find that
for many of the events it is similar to efficiencies inferred for active
galactic nuclei. There are, however, large systematic uncertainties in the
measured efficiency due to model degeneracies between the efficiency and the
mass of the disrupted star, and these must be reduced before we can
definitively resolve the emission mechanism of individual TDEs.
Tidal disruption events (TDEs) offer a unique opportunity to study a single
super-massive black hole (SMBH) under feeding conditions that change over
timescales of days or months. However, the primary mechanism for generating
luminosity during the flares remains debated. Despite the increasing number of
observed TDEs, it is unclear whether most of the energy in the initial flare
comes from accretion near the gravitational radius or from circularizing debris
at larger distances from the SMBH. The energy dissipation efficiency increases
with decreasing radii, therefore by measuring the total energy emitted and
estimating the efficiency we can derive clues about the nature of the emission
mechanism. Here we calculate the integrated energy, emission timescales, and
average efficiencies for the TDEs using the Modular Open Source Fitter for
Transients ({tt MOSFiT}). Our calculations of the total energy generally yield
higher values than previous estimates. This is predominantly because, if the
luminosity follows the mass fallback rate, TDEs release a significant fraction
of their energy long after their light curve peaks. We use {tt MOSFiT} to
calculate the conversion efficiency from mass to radiated energy, and find that
for many of the events it is similar to efficiencies inferred for active
galactic nuclei. There are, however, large systematic uncertainties in the
measured efficiency due to model degeneracies between the efficiency and the
mass of the disrupted star, and these must be reduced before we can
definitively resolve the emission mechanism of individual TDEs.
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