BEGIN:VCALENDAR VERSION:2.0 PRODID:-//linuxsoftware.nz//NONSGML Joyous v1.4//EN BEGIN:VEVENT SUMMARY:Late-time tails in nonlinear evolutions of merging black holes DTSTART:20250220T143000Z DTEND:20250220T160000Z DTSTAMP:20260914T174509Z UID:44c5c722-48ba-4a11-992b-3c08136bf5b1 SEQUENCE:2 CREATED:20250218T152926Z DESCRIPTION:It has been known for many years\, that the boundary condition alter the tails of scalar radiation in spherically symmetric spacetimes. It was however an open question to which extent this result generalises to gravitational waves in vacuum. Using the pseudospectral SpEC code we we u ncover for the first time late-time gravitational-wave tails in fully nonl inear 3+1 dimensional numerical relativity simulations. We achieve this re sult by exploiting the strong magnification of late-time tails due to bina ry eccentricity and showcase here the tail presence in head-on configurati ons for several mass ratios close to unity. The impact of the boundary con ditions is uncovered in a systematic study\, showing that the boundary con ditions are the primary source for errors in the tails. The simulations ar e also compared to perturbative evolutions\, which display striking agreem ent with full nonlinear ones. LAST-MODIFIED:20250218T153049Z LOCATION:DF Seminar Room (2-8.3)\, 2nd floor of Physics Building URL:http://df.vps.tecnico.ulisboa.pt/pt/eventos/late-time-tails-in-nonline ar-evolutions-of-merging-black-holes/ X-ALT-DESC;FMTTYPE=text/html:

It has been known f or many years\, that the boundary condition alter the tails of scalar radi ation in spherically symmetric spacetimes. It was however an open question to which extent this result generalises to gravitational waves in vacuum. Using the pseudospectral SpEC code we we uncover for the first time late- time gravitational-wave tails in fully nonlinear 3+1 dimensional numerical relativity simulations.

We achieve this result by exploiting th e strong magnification of late-time tails due to binary eccentricity and s howcase here the tail presence in head-on configurations for several mass ratios close to unity. The impact of the boundary conditions is uncovered in a systematic study\, showing that the boundary conditions are the prima ry source for errors in the tails.

The simulations are also comp ared to perturbative evolutions\, which display striking agreement with fu ll nonlinear ones.

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