@PhDThesis{Assis:2021:AcOnGr,
author = "Assis, Adam Smith Gontijo Brito de",
title = "Acoplamento entre ondas gravitacionais e plasmas fortemente
magnetizados em bin{\'a}rias de estrelas de n{\^e}utrons",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "2021",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2020-10-15",
keywords = "ondas gravitacionais, estrelas de n{\^e}utrons, ondas MHD, short
GRBs, ondas eletromagn{\'e}ticas, gravitational waves, neutron
star, magneto-hydrodynamics waves, eletromagnetic waves.",
abstract = "A coalesc{\^e}ncia de bin{\'a}rias de estrelas de n{\^e}utrons
produz quantidade significativa de ondas gravitacionais. A fonte
GW170817 detectada pelo Advanced LIGO e Virgo associada ao
GRB170817A inaugurou a astronomia multi-mensageira, confirmando o
modelo de que as estrelas de n{\^e}utrons s{\~a}o tamb{\'e}m
progenitores de eventos Gamma- Ray Bursts de curta
dura{\c{c}}{\~a}o. A massa total da bin{\'a}ria detectada foi
de 2, 73M, produziu um GRB de curta dura{\c{c}}{\~a}o 2±0, 5s e
com energia isotr{\'o}pica equivalente de ~ 1039\−1040J.
Essas emiss{\~o}es s{\~a}o produzidas de acordo com o modelo de
fireball, que consiste em pares el{\'e}tron-p{\'o}sitron,
radia{\c{c}}{\~a}o e mat{\'e}ria bari{\^o}nica. Esta
{\'u}ltima absorve a maior parte da energia da explos{\~a}o,
chegando a alcan{\c{c}}ar fatores de Lorentz ( ) da ordem de
102-103. Devido aos intensos campos magn{\'e}ticos de estrelas de
n{\^e}utrons e ao plasma fortemente magnetizado circundante a
essas fontes de OGs, os modos Alfv{\'e}n e magneto-ac{\'u}stico
de ondas magneto-hidrodin{\^a}micas s{\~a}o excitados pelas
polariza{\c{c}}{\~o}es das OGs, × e +, respectivamente. As ondas
MHD excitadas, por sua vez, carregam energia atrav{\'e}s do
plasma, sugerindo um mecanismo alternativo para a
acelera{\c{c}}{\~a}o da mat{\'e}ria com altos fatores de
Lorentz. A amplitude da OG depende da frequ{\^e}ncia do sistema,
por conseguinte, a energia depositada no plasma depende da
frequ{\^e}ncia da radia{\c{c}}{\~a}o gravitacional. N{\'o}s
encontramos o conjunto fechado de equa{\c{c}}{\~o}es que
descrevem o plasma MHD ideal excitado pelas OGs emitidas pela
bin{\'a}ria de estrelas de n{\^e}utrons. Calculamos a energia
transferida entre as ondas durante a fase inspiral da
coalesc{\^e}ncia. Nossos resultados mostram que as
frequ{\^e}ncias mais baixas contribuem significativamente para a
absor{\c{c}}{\~a}o da energia no plasma e que, para o modo
magnetoss{\^o}nico, a energia armazenada pode alcan{\c{c}}ar
valores ~ 1036J, quando n{\'o}s consideramos as
condi{\c{c}}{\~o}es do sistema GW170817 emitindo OG na faixa ~
100 Hz at{\'e} ~ 1, 61 kHz. Com c{\'a}lculo an{\'a}logo, para o
modo Alfv{\'e}n, a energia armazenada pelo acoplamento pode
alcan{\c{c}}ar valores ~ 1035J dentro da faixa de
frequ{\^e}ncias. Mostramos que o o vector de Poynting e a
press{\~a}o de radia{\c{c}}{\~a}o produzidos pela
intera{\c{c}}{\~a}o da OG e plasma podem ter pap{\'e}is
importantes na gera{\c{c}}{\~a}o do fluxo
ultrarrelativ{\'{\i}}stico de GRBs. A energia observada para o
GRB170817A, em princ{\'{\i}}pio, pode ser explicada se o
{\^a}ngulo formado entre a orienta{\c{c}}{\~a}o do campo
magn{\'e}tico ambiente e a dire{\c{c}}{\~a}o de
propaga{\c{c}}{\~a}o das OGs {\'e} de /2. Todos os resultados
s{\~a}o obtidos, semi-analiticamente, para as ondas MHD
interagindo coerentemente com as OGs. ABSTRACT: Coalescence of
binary neutron stars produces a significant amount of
gravitational waves. The source GW170817 detected by Advanced LIGO
and Virgo associated with GRB170817A inaugurated the
multi-messenger astronomy, confirming the model that neutron stars
are also progenitors of short Gamma-Ray Burst events. The total
mass of the detected binary was 2.73M, and it produced a short GRB
with duration of 2 ± 0.5s and equivalent isotropic energy of ~
1039 \− 1040 J. This emission is produced according to the
fireball model, which consists of electronpositron pairs,
radiation, and baryonic matter. The last one absorbs most of the
energy from the explosion, reaching Lorentz factors ( ) in the
order of 102 - 103. Due to the intense magnetic fields of the
neutron stars and the strongly magnetized plasma surrounding these
sources of GWs, the Alfv{\'e}n and magneto-acoustic modes of
magneto-hydrodynamic waves are excited, respectively, by the
polarizations × and + of the GWs. The excited MHD waves, in turn,
carry energy through the plasma, suggesting an alternative
mechanism for the acceleration of matter with high Lorentz
factors. The GW amplitude depends on the frequency of the system,
therefore, the energy deposited in the plasma depends on the
frequency of the gravitational radiation. We found the closed set
of equations describing the ideal MHD plasma excited by the GWs
emitted by the neutron binary star. We calculated the energy
transferred between the waves during the inspiral phase of the
coalescence. Our results show that the lower frequencies also
contribute to the absorption of energy in the plasma and that, for
the magnetosonic mode, the stored energy can reach values ~ 1036J,
when we consider similar conditions as GW170817 emitting GW in the
range ~ 100 Hz up to ~ 1.61 kHz. With an analogous calculation,
for the Alfv{\'e}n mode, the energy stored by the coupling can
reach values 1035J within the frequency range. We show that the
Poynting vector and the radiation pressure produced by the
interaction of GW - plasma can play an important role in the
generation of the ultra-relativistic flow of GRBs. The energy
observed for GRB170817A, in principle, can be explained if the
angle formed between the orientation of the background magnetic
field and the GW propagation direction is /2. All results are
obtained, semi-analytically, for the MHD waves interacting
coherently with the GWs.",
committee = "Aguiar, Odylio Denys de (presidente) and Miranda, Oswaldo Duarte
(orientador) and Wuensche, Carlos Alexandre and Tinto, Massimo and
Oliveira, Manuel M{\'a}ximo Bastos Malheiro de and Horvath, Jorge
Ernesto",
englishtitle = "Coupling between gravitational waves and a strongly magnetized
plasma in binaries of neutron stars",
language = "pt",
pages = "221",
ibi = "8JMKD3MGP3W34R/43CQ27S",
url = "http://urlib.net/ibi/8JMKD3MGP3W34R/43CQ27S",
targetfile = "publicacao.pdf",
urlaccessdate = "03 maio 2024"
}