Evidence for event horizons: Long-lived modes in ultracompact objects
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Evidence for event horizons : Long-lived modes in ultracompact objects. / Macedo, Caio F. B.; Crispino, Luis C. B.; Cardoso, Vitor; Okawa, Hirotada; Pani, Paolo.
I: International Journal of Modern Physics D, Bind 24, Nr. 9, 1542023, 08.2015.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Evidence for event horizons
T2 - 7th Black Holes Workshop
AU - Macedo, Caio F. B.
AU - Crispino, Luis C. B.
AU - Cardoso, Vitor
AU - Okawa, Hirotada
AU - Pani, Paolo
PY - 2015/8
Y1 - 2015/8
N2 - Gravitational compact astrophysical objects are excellent laboratories to test the strong field regime of theories of gravity. Among these compact objects, lies the ultracompact class: stellar structures that possess a light ring (circular null geodesic). Such ultracompact stars were presented in literature in the earlier solutions of general relativity, and some are claimed to be good candidates to the supermassive objects present at the center of galaxies. In this paper, we present evidences for the claim that compact objects with a light ring should be black holes, based on the existence of long-lived modes obtained through a first-order perturbation theory. These first-order long-lived modes can source nonlinear terms which could turn the star unstable. We show, in particular, a comparison between modes computed through an exact direct integration and through the WKB approximation. Moreover, we present the time evolution of wavepackets for different field configurations. We conjecture some possible outcomes of the nonlinear instability. The discussion presented in this work complements our previous paper [Phys. Rev. D 90 (2014) 044069].
AB - Gravitational compact astrophysical objects are excellent laboratories to test the strong field regime of theories of gravity. Among these compact objects, lies the ultracompact class: stellar structures that possess a light ring (circular null geodesic). Such ultracompact stars were presented in literature in the earlier solutions of general relativity, and some are claimed to be good candidates to the supermassive objects present at the center of galaxies. In this paper, we present evidences for the claim that compact objects with a light ring should be black holes, based on the existence of long-lived modes obtained through a first-order perturbation theory. These first-order long-lived modes can source nonlinear terms which could turn the star unstable. We show, in particular, a comparison between modes computed through an exact direct integration and through the WKB approximation. Moreover, we present the time evolution of wavepackets for different field configurations. We conjecture some possible outcomes of the nonlinear instability. The discussion presented in this work complements our previous paper [Phys. Rev. D 90 (2014) 044069].
KW - Event horizons
KW - long-lived modes
KW - ultracompact stars
KW - gravastars
KW - GRAVITATIONAL-WAVE DETECTORS
KW - STARS
U2 - 10.1142/S0218271815420237
DO - 10.1142/S0218271815420237
M3 - Journal article
VL - 24
JO - International Journal of Modern Physics D
JF - International Journal of Modern Physics D
SN - 0218-2718
IS - 9
M1 - 1542023
Y2 - 18 December 2014 through 19 December 2014
ER -
ID: 300071142