BEGIN:VCALENDAR VERSION:2.0 PRODID:-//linuxsoftware.nz//NONSGML Joyous v1.4//EN BEGIN:VEVENT SUMMARY:Black Hole Ringdown Spirals DTSTART:20260212T143000Z DTEND:20260212T160000Z DTSTAMP:20260423T180851Z UID:30167857-515e-428e-9c43-2c3b61856f05 SEQUENCE:2 CREATED:20260211T092440Z DESCRIPTION:The post-merger of a binary black hole coalescence\, known as the ringdown\, provides important information about the remnant black hole . While dominated by quasi-normal mode emission at early times\, the late time emission is governed by a power-law tail. The amplitude and phase pro perties of the former are found by fitting to numerical relativity wavefor ms\, while the latter are not typically extracted from such simulations du e to extrapolation artifacts (except in rare cases). Most of these studies focus on fitting to either the gravitational wave polarizations or amplit ude. In this talk\, I will instead focus on the instantaneous waveform pha se\, and show how it constitutes an attractor-repulsor system arising from the interference between quasi-normal modes and the power-law tail. I wil l discuss prospects for inferring the properties of the power-law tail in quasi-circular waveforms from numerical relativity\, where they are buried beneath extraction artifacts. LAST-MODIFIED:20260211T092450Z LOCATION:DF Seminar Room (2-8.3)\, 2nd floor of Physics Building URL:http://df.vps.tecnico.ulisboa.pt/pt/eventos/black-hole-ringdown-spiral s/ X-ALT-DESC;FMTTYPE=text/html:

The post-merger of a binary black hole coalescence\, known as the ringdown\, provides importa nt information about the remnant black hole. While dominated by quasi-norm al mode emission at early times\, the late time emission is governed by a power-law tail.

The amplitude and phase properties of the former are found by fitting to numerical relativity waveforms\, while the latter are not typically extracted from such simulations due to extrapolation ar tifacts (except in rare cases). Most of these studies focus on fitting to either the gravitational wave polarizations or amplitude.

In thi s talk\, I will instead focus on the instantaneous waveform phase\, and sh ow how it constitutes an attractor-repulsor system arising from the interf erence between quasi-normal modes and the power-law tail. I will discuss p rospects for inferring the properties of the power-law tail in quasi-circu lar waveforms from numerical relativity\, where they are buried beneath ex traction artifacts.

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