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<p>Dear Everyone,</p>
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<p>Next week we will have a seminar by <span>James Gillanders</span>.</p>
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<p>Best,<br>
Haakon (on behalf of the organizers)<br>
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<b data-stringify-type="bold">When and where: Thursday 25th April, 13:15 in A5:1003</b></div>
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Speaker: James Gillanders, Postdoc at Oxford<br>
Title: Identifying heavy r-process elements in the spectra of two compact binary mergers<span aria-label="" class="c-mrkdwn__br" data-stringify-type="paragraph-break"></span><br>
Abstract: Kilonovae are the optical counterpart associated with the radioactive decay of an ensemble of freshly synthesised unstable isotopes produced by the rapid neutron-capture process (r-process). The r-process is responsible for synthesising approximately
half of all elements beyond the iron peak. Direct observations of r-process nucleosynthesis are limited; to date, the only observed production site remains binary neutron star mergers. These merger systems evolve rapidly and are intrinsically faint compared
to virtually all other known extragalactic transients, and so remain elusive to wide-field surveys optimised to search for such events. While there are proposed detections of ~10 kilonova events, only two of these have been observed spectroscopically – AT2017gfo/GRB170817A
and AT2023vfi/GRB230307A. In this talk, I will present the spectral observations that exist for kilonovae, with a focus on the heavy r-process element identifications that can be extracted from such observations. Specifically, I will present the results of
my recent work to constrain the composition of AT2017gfo, both at early and late times. I will also highlight new work on the exciting JWST spectral observations of AT2023vfi, and what we can extract from these near-infrared, late-time observations.</div>
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