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Abstract: First generation metal-free stars, referred
to as population III (Pop III) stars, are believed to be the first
objects to form out of the pristine gas in the very early
Universe. Pop III stars have different structures from the current
generation of stars and are important for generating heavy elements
and shaping subsequent star formation. However, it is very challenging
to directly detect Pop III stars given their high redshifts and short
life-times. In this work, we propose a novel signature for detecting
Pop III stars through their tidal disruption events (TDEs) by massive
black holes. We model the emission properties and calculate the
expected rates for these unique TDEs in the early Universe at z
~10. We find that Pop III star TDEs have much higher mass fallback
rates compared to normal TDEs in the local universe and are therefore
rather luminous, rendering them feasible for detection. They also have
very long observed flare evolution timescale, making it more likely to
detect such TDEs during their rising phase. We further demonstrate
that a large fraction of the TDE emissions are redshifted to infrared
wavelengths and can be detected by the James Webb Space Telescope and
the Nancy Grace Roman Space Telescope. Lastly, the TDE rate
sensitively depends on the black hole mass function in the early
Universe. We find a promising Pop III star TDE detection rate of up to
a few tens per year using the Nancy Grace Roman Space Telescope.
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