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BEGIN:VEVENT
SUMMARY:The Speed of Gravity
DTSTART;VALUE=DATE-TIME:20210331T073000Z
DTEND;VALUE=DATE-TIME:20210331T080000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5148@indico.math.cnrs.fr
DESCRIPTION:Speakers: Claudia De Rham ()\nhttps://indico.math.cnrs.fr/even
t/5766/contributions/5148/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5148/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Effective two-body approach to the hierarchical three-body problem
DTSTART;VALUE=DATE-TIME:20210330T074500Z
DTEND;VALUE=DATE-TIME:20210330T080000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5246@indico.math.cnrs.fr
DESCRIPTION:Speakers: Adrien Kuntz (Scuola Normale Superiore\, Pisa)\nThe
three body-problem\, even in the simple Newtonian case\, exhibits very ric
h dynamical behaviors. The study of a hierachical configuration\, in which
a close inner binary is orbited by a distant perturber\, has been initiat
ed by Lidov and Kozai in the 60's. The eccentricity oscillations that they
discovered is particularly relevant to gravitational wave astronomy. On t
he other hand\, several efficient tools have been developed to study the g
eneral relativistic two-body problem. In this talk\, I will present how on
e can extend the two-body effective field theory (EFT) approach to the set
up of a hierarchical three-body problem. Besides introducing a new expansi
on parameter consisting in the ratio of semimajor axes of the two orbits\,
our approach builds on the fact that one can treat the inner binary itsel
f as an effective spinning point-particle. I will present in some details
how this identification is performed.\n\nhttps://indico.math.cnrs.fr/event
/5766/contributions/5246/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5246/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Towards a gravitational wave map of the Local Group of galaxies
DTSTART;VALUE=DATE-TIME:20210401T093000Z
DTEND;VALUE=DATE-TIME:20210401T100000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5161@indico.math.cnrs.fr
DESCRIPTION:Speakers: Elena Rossi ()\nhttps://indico.math.cnrs.fr/event/57
66/contributions/5161/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5161/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Experimental challenges to astrophysical reach of ground-based det
ectors
DTSTART;VALUE=DATE-TIME:20210330T150000Z
DTEND;VALUE=DATE-TIME:20210330T153000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5145@indico.math.cnrs.fr
DESCRIPTION:Speakers: Gabriela Gonzalez ()\nhttps://indico.math.cnrs.fr/ev
ent/5766/contributions/5145/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5145/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Multi-messenger studies with GRANDMA
DTSTART;VALUE=DATE-TIME:20210401T101500Z
DTEND;VALUE=DATE-TIME:20210401T103000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5257@indico.math.cnrs.fr
DESCRIPTION:Speakers: Sarah Antier (APC)\nMulti-messenger studies have bee
n vitalized by GW170817 in which diverse messengers - photons and gravitat
ional waves - provide a new picture of the collision of two neutron stars.
In this talk\, I will first review briefly how coherent analysis of the m
essengers can not only better constrain the astrophysical scenarios at pla
y\, but also further knowledge on the cosmology and nuclear physics side.
In a second half\, I will present the Global Rapid Advanced Network Devote
d to the Multi-messenger Addicts (GRANDMA\, PI Sarah Antier)\, which aims
to identify and characterize the electromagnetic counterparts of gravitati
onal-wave sources. I will detail the consortium\, its characteristics and
public tools provided for time-domain astronomy. I will finish with a summ
ary of our scientific achievements and future prospects for GRANDMA.\n\nht
tps://indico.math.cnrs.fr/event/5766/contributions/5257/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5257/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dynamics of Screening in Modified Gravity
DTSTART;VALUE=DATE-TIME:20210401T123000Z
DTEND;VALUE=DATE-TIME:20210401T124500Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5261@indico.math.cnrs.fr
DESCRIPTION:Speakers: Lotte ter Haar (SISSA)\nGravitational theories diffe
ring from General Relativity may explain the accelerated expansion of the
Universe without a cosmological constant. However\, their viability crucia
lly depends on a “screening mechanism” needed to suppress\, on small s
cales\, the fifth force driving the cosmological acceleration. I will disc
uss a scalar-tensor theory with first-order derivative self-interactions e
xhibiting such a mechanism\, and present screened solutions in this theory
for both non-relativistic and relativistic stars. Then\, I will discuss t
he stability of these solutions and present our results from numerically e
volving them in the strong-field\, highly dynamical regime.\n\nhttps://ind
ico.math.cnrs.fr/event/5766/contributions/5261/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5261/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Parameter estimation for inspiralling MBH binaries in LISA
DTSTART;VALUE=DATE-TIME:20210401T121500Z
DTEND;VALUE=DATE-TIME:20210401T123000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5258@indico.math.cnrs.fr
DESCRIPTION:Speakers: Alberto Mangiagli (APC)\nMassive black hole binaries
(MBHBs) of $10^5 \\\, \\rm M_\\odot - 3 \\times 10^7 \\\, \\rm M_\\odot $
merging in low redshift galaxies ($z\\le4$) are sufficiently loud to be d
etected weeks before coalescence with LISA. This allows us to perform the
parameter estimation *on the fly*\, i.e. as a function of the time to coal
escence during the inspiral phase\, relevant for early warning of the plan
ned LISA protected periods and for searches of electromagnetic counterpart
s.\nI will present the results for the estimates of the sky position\, lum
inosity distance\, chirp mass and mass ratio uncertainties as function of
time left before merger for a wide range of sources. While we find general
ly good constrains for the latter three\, the sky position appears to be d
etermined with sufficient accuracy only for relatively light and nearby sy
stems and only close to merger. I will also discuss the multi-messenger po
tentials and possible synergies with electromagnetic facilities.\n\nhttps:
//indico.math.cnrs.fr/event/5766/contributions/5258/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5258/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Catching black holes with tidal disruption events
DTSTART;VALUE=DATE-TIME:20210401T120000Z
DTEND;VALUE=DATE-TIME:20210401T121500Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5256@indico.math.cnrs.fr
DESCRIPTION:Speakers: martina toscani (Università degli studi di Milano)\
nTidal disruption events (TDEs) take place when a star orbiting around a b
lack hole (BH) is fully or partially disrupted by the black hole tides. Th
is occurrence can be used as a way to reveal the presence of quiescent BHs
through the Universe. With this talk\, I will first describe general feat
ures of TDEs. Then\, I will explore the possibility of detecting them via
gravitational waves (GWs) with future space-based interferometers. Finally
\, I will illustrate how the GW background from these events could allow u
s to better constrain the elusive population of intermediate-mass BHs and
to map their distribution up to redshift 3.\n\nhttps://indico.math.cnrs.fr
/event/5766/contributions/5256/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5256/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dynamical process impact on CBC GW background
DTSTART;VALUE=DATE-TIME:20210401T081500Z
DTEND;VALUE=DATE-TIME:20210401T083000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5270@indico.math.cnrs.fr
DESCRIPTION:Speakers: Carole PERIGOIS (LAPP\, Annecy)\nNowdays we are able
to resolve more and more compact binary merger events as our detector sen
sitivities improve. However the detected sources are loud and close events
\, suggesting a large number of non-resolved binary mergers participating
to a CBC background. I will present this background computed from a popula
tion I/II stars ehanced with a young cluster population simulated from dyn
amical processes in the 2G detectors (LIGO\, Virgo\, KAGRA) frequency rang
e. I will focus in particular on the contribution of BBHs that is expected
to dominate. Finally I will discuss the detectability of the background w
ith 2G detectors.\n\nhttps://indico.math.cnrs.fr/event/5766/contributions/
5270/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5270/
END:VEVENT
BEGIN:VEVENT
SUMMARY:The massive binary black hole population across cosmic time seen u
nder a semi-analytical perspective
DTSTART;VALUE=DATE-TIME:20210401T080000Z
DTEND;VALUE=DATE-TIME:20210401T081500Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5269@indico.math.cnrs.fr
DESCRIPTION:Speakers: David Izquierdo-Villalba (Università degli studi di
Milano-Bicocca)\nCurrent and future surveys are going to shed light on th
e formation and evolution of massive black hole binaries. While current pu
lsar-timing experiments will detect a gravitational wave (GW) background s
ignal generated by the incoherent superposition of GWs from the whole popu
lation of massive binary black holes\, the forthcoming LISA experiment wil
l likely detect singular coalescences events. In this scenario\, theoretic
al studies are vital to provide forecasts for these experiments and to hel
p to interpret their results within a consistent cosmological picture. In
this work\, we contribute to these theoretical works by presenting prelimi
nary results about binary black hole evolution by using the state-of-the-a
rt semianalytical model L-Galaxies. The main advantage of this model is it
s flexibility to be run on the dark matter merger trees of the Millennium
suite of simulations whose different box sizes and dark matter mass resolu
tion offer the capability to explore different physical processes undergon
e by galaxies over a wide range of scales and environments. In particular\
, L-Galaxies includes a proper treatment for the spin and growth evolution
presented in Izquierdo-Villalba et al. 2020\, generating a reliable popul
ation of massive black holes at z<4. By linking this model with some physi
cally-motivated assumptions about the pairing and hardening phase evolutio
n of the binary systems\, we can obtain predictions about how the massive
binary population evolves with time\, their expected merger rates and what
are the exact properties of their hosting galaxies.\n\nhttps://indico.mat
h.cnrs.fr/event/5766/contributions/5269/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5269/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Searching binary black holes in Milky Way and other nearby galaxie
s with LISA
DTSTART;VALUE=DATE-TIME:20210401T074500Z
DTEND;VALUE=DATE-TIME:20210401T080000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5255@indico.math.cnrs.fr
DESCRIPTION:Speakers: Rafia SARWAR (Institute of Space Technology\, Islama
bad\, Pakistan)\nIn 2034\, within the rapidly changing landscape of gravit
ational-wave astronomy\, the Laser interferometer Space Antenna will be t
he first space-based detector that will observe the gravitational spectra
in the millihertz frequency band. It has recently been proposed that numer
ous LIGO/VIRGO sources will also be detectable by LISA. LISA will be able
to detect binary black holes from our Milky Way galaxy and its neighbourho
od\, evolving from their early inspiral stages. Interestingly\, the source
s that appear to be circular in the LIGO band may be eccentric in the LISA
band\, depending on the earlier stages of their evolution. We aim to expl
ore the gravitational-waves emitted from black hole binaries in our Milky
Way galaxy and its neighbourhood\, as they are expected to be observable w
ith LISA. The study of the properties of these gravitational-waves will en
able us to predict their progenitor stars\, formation channels\, metallici
ties\, astrophysical conditions of the formation of these binaries\, and t
raceback earlier stages of their evolution. We combine the Latte simulatio
n from the Feedback in relativistic environments (FIRE-2) project with the
next-generation population synthesis code POSYDON to investigate the dete
ctability of the binary black hole population in both the LISA and the LIG
O frequency bands\, as a function of eccentricity and their horizon distan
ces\, using a Monte-Carlo approach. Also\, we study how one can disentangl
e different formation channels of these binaries using LISA\, and estimat
e the rate at which these binaries form in the Milky Way galaxy and other
nearby galaxies. These explorations will identify the primary properties o
f the binary systems that will be detectable within the range of LISA.\n\n
https://indico.math.cnrs.fr/event/5766/contributions/5255/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5255/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Discriminating between different scenarios for the formation and e
volution of massive black holes with LISA
DTSTART;VALUE=DATE-TIME:20210401T073000Z
DTEND;VALUE=DATE-TIME:20210401T074500Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5254@indico.math.cnrs.fr
DESCRIPTION:Speakers: Alexandre Toubiana (APC/IAP)\nDifferent scenarios fo
r the formation and evolution of massive black holes lead to different pre
dictions for the population of massive black holes in the Universe. By rev
erse engineering the problem\, we can use LISA observations to discriminat
e between different scenarios. However\, the Universe is unlikely to be de
scribed by a single model. This can be accounted for by introducing mixing
fractions between the different models.\nIn this talk\, I will present si
mulated results for the inference of the mixing fraction between two model
s from LISA observations using a hierarchical Bayesian framework. I will a
lso discuss of the robustness of this approach by using different models t
o generate the simulated data.\n\nhttps://indico.math.cnrs.fr/event/5766/c
ontributions/5254/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5254/
END:VEVENT
BEGIN:VEVENT
SUMMARY:The cosmic merger rate density of compact binaries
DTSTART;VALUE=DATE-TIME:20210401T071500Z
DTEND;VALUE=DATE-TIME:20210401T073000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5253@indico.math.cnrs.fr
DESCRIPTION:Speakers: Filippo Santoliquido (University of Padova)\nWith th
e recent publication of the second gravitational wave transient catalog by
the LIGO-Virgo collaboration (LVC)\, the number of binary compact object
mergers has risen dramatically\, from a dozen to ~ 50 events. From these d
etections\, the LVC inferred the merger rate density both in the local Uni
verse and as a function of redshift. It is then of foremost importance to
compare the merger rate density predicted with different astrophysical mod
els with the value inferred by LVC. In my talk\, I will present a semi-ana
lytic model that evaluates the cosmic merge rate density\, by taking into
account the cosmic star formation rate density and the metallicity evoluti
on of stars across cosmic time. These are then combined with catalogues of
merging compact binaries. I have considered binaries that form in isolati
on versus dynamical binaries. My results indicate that dynamical binaries
are much less sensitive to metallicity than isolated binaries (Santoliquid
o et al. 2020 - arXiv: 2004.09533). Furthermore\, I have explored the impa
ct of various binary evolution processes on the merger rate density. For e
xample\, when I vary the common envelope ejection efficiency parameter fro
m $\\alpha_{CE}$=7 to 0.5\, the local merger rate density of binary neutro
n stars varies from 10$^3$ to 20 Gpc$^{-3}$ yr$^{-1}$\, whereas the local
merger rates of binary black holes and black hole - neutron star binaries
vary just by a factor of ~2-3. I will also show that by propagating the u
ncertainties of the metallicity evolution model on the merger rate density
\, the binary black hole merger rate can change by one order of magnitude
within 50% credible interval (Santoliquido et al. 2021 - arXiv: 2009.03911
).\n\nhttps://indico.math.cnrs.fr/event/5766/contributions/5253/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5253/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hierarchical triples can explain LIGO-Virgo mergers
DTSTART;VALUE=DATE-TIME:20210401T070000Z
DTEND;VALUE=DATE-TIME:20210401T071500Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5252@indico.math.cnrs.fr
DESCRIPTION:Speakers: Giacomo Fragione (Northwestern University)\nThe rece
nt discovery of gravitational waves has opened new horizons. The LIGO-Virg
o events have made possible to estimate rates\, masses\, eccentricities\,
and projected spins of merging black holes (BHs) for the fist time. The as
trophysical origin of these mergers is among the most puzzling open questi
ons of our time. Two primary channels have been proposed to explain the ob
served population of merging BHs and NSs: field binary evolution and dynam
ical formation in a cluster environment. Observations show that about one
fourth of massive stars is in triple systems\, comprised of an inner binar
y orbited by a third companion. Despite being rarer than binaries\, a larg
e fraction of triples can merge as a result of the Kozai-Lidov mechanism\,
imposed on the inner binary by the field of the third companion. Within c
urrent uncertainties\, triples can potentially account for most of the obs
erved events. Remarkably\, triples are expected to produce many mergers wi
th relatively high total mass and low mass ratios relative to the other fo
rmation channels. The triple scenario is definitively the third pathway to
compact object mergers.\n\nhttps://indico.math.cnrs.fr/event/5766/contrib
utions/5252/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5252/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Study of Neutron Star in the presence of Dark Matter
DTSTART;VALUE=DATE-TIME:20210331T134500Z
DTEND;VALUE=DATE-TIME:20210331T140000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5239@indico.math.cnrs.fr
DESCRIPTION:Speakers: Harish Chandra Das (Institute of Physics\, Bhubanesw
ar\, Odisha\, India)\nNeutron stars (NSs)\, being one of the most enigmati
c stellar remnants with incredibly dense core and sturdy crust\, can be co
nsidered as the best laboratory in the universe to appraise many astrophys
ical models of the strong gravitational field regime. We analyse the effec
ts of dark matter on the properties and curvature of the NS with the help
of relativistic mean-field (RMF) formalism using NL3\, G3 and IOPB-I param
eter sets. We thoroughly investigate the influence of dark matter candida
te on the mass-radius profile of the NS. The impact of dark matter on the
moment of inertia for static and rotating NS has also been calculated and
studied [1]. We calculate and examine the Riemann tensor\, Kretschmann sca
lar\, Ricci tensor and RicciScalar along with the variation of baryon dens
ity\, mass and radius of the NS in the presence of the dark matter [2].
The dependence of curvature of the NS on the nature of the RMF parameter s
et has also been explored with the softer and stiffer equation of state.\n
\n[1] H. C. Das\, A. Kumar\, B. Kumar\, et al.\, MNRAS 495\, 4893 (2020).
\n[2] H. C. Das\, A. Kumar\, B. Kumar\, S. Biswal\, and S. Patra\, Journa
l of Cosmology and Astroparticle Physics2021\, 007 (2021).\n\nhttps://indi
co.math.cnrs.fr/event/5766/contributions/5239/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5239/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mapping the inhomogeneous Universe with Standard Sirens: Degenerac
y between inhomogeneity and modified gravity theories
DTSTART;VALUE=DATE-TIME:20210331T133000Z
DTEND;VALUE=DATE-TIME:20210331T134500Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5271@indico.math.cnrs.fr
DESCRIPTION:Speakers: Marios Kalomenopoulos (University of Edinburgh)\nThe
detection of gravitational waves (GWs) and an accompanying electromagneti
c (E/M) counterpart have been suggested as a future probe for cosmology an
d theories of gravity. In this work\, we present calculations of the lumin
osity distance of sources taking into account inhomogeneities in the matte
r distribution that are predicted in numerical simulations of structure fo
rmation. In addition\, we show that inhomogeneities resulting from cluster
ing of matter can mimic certain classes of modified gravity theories\, or
other effects that dampen GW amplitudes\, and deviations larger than $\\de
lta \\nu \\sim \\mathcal{O}(0.1)\\ (99\\%\\ \\rm{C.L.})$ to the extra fric
tion term $\\nu$\, from zero\, would be necessary to distinguish them. For
these\, we assume mock GWs sources\, with known redshift\, based on binar
y population synthesis models\, between redshifts $z=0$ and $z=5$. We show
that future GW detectors\, like Einstein Telescope or Cosmic Explorer\,
will be needed for strong constraints on the inhomogeneity parameters and
breaking the degeneracy between modified gravity effects and matter anisot
ropies by measuring $\\nu$ at $5 \\%$ and $1 \\%$ level with $100$ and $35
0$ events respectively.\n\nhttps://indico.math.cnrs.fr/event/5766/contrib
utions/5271/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5271/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Constraining the Hubble constant and modified GW propagation with
LIGO/Virgo dark sirens and galaxy catalogs
DTSTART;VALUE=DATE-TIME:20210331T131500Z
DTEND;VALUE=DATE-TIME:20210331T133000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5245@indico.math.cnrs.fr
DESCRIPTION:Speakers: Mancarella Michele (Université de Genève)\nI will
present the methodology for constraining the Hubble parameter and modified
GW propagation with “dark sirens” (namely\, compact binary coalescenc
es without an electromagnetic counterpart) and galaxy catalogs.\nI will in
troduce in particular some relevant improvements to the treatment of the l
atter\, such as their completeness\, and discuss the correct treatment of
selection bias. I will then show results that make use of the recent GWTC-
2 catalogue\, presenting the most accurate measurement of H0 from dark sir
ens alone\, new bounds on modified GW propagation\, commenting on the role
of EM counterparts and discussing relevant systematics and the interplay
with astrophysical parameters.\n\nhttps://indico.math.cnrs.fr/event/5766/c
ontributions/5245/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5245/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cosmology with dark gravitational wave sources
DTSTART;VALUE=DATE-TIME:20210331T130000Z
DTEND;VALUE=DATE-TIME:20210331T131500Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5242@indico.math.cnrs.fr
DESCRIPTION:Speakers: Suvodip Mukherjee (University of Amsterdam)\nSeveral
observations using electromagnetic signal have led to a paradigm shift in
our understanding of the Universe\, with the realization that two unknown
quantities - namely dark matter and dark energy - constitute about 95% of
the Universe\, even though their existence could not be explained by the
known laws of physics and fundamental particles discovered until now. More
over\, measurements of the current expansion rate of the Universe\, known
as the Hubble constant - using several independent methods based on observ
ations of different cosmological probes have reached an enigmatic and star
tling conclusion. These Hubble constant measurements are strongly inconsis
tent with each other. This discrepancy has led us to question the foundati
ons of cosmology\, indicating either an entirely new physics or unknown sy
stematics. I will discuss how the gravitational wave observations can play
a pivotal role in resolving the tension in the value of the Hubble consta
nt and provide a better understanding of the constituents of the Universe.
I will explain novel techniques that will enable us to map the expansion
history of the Universe up to high redshift using binary black holes and h
ow it can peer into new territories of fundamental physics that are curren
tly unexplored from electromagnetic observations.\n\nhttps://indico.math.c
nrs.fr/event/5766/contributions/5242/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5242/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Theoretical uncertainties for cosmological phase transitions
DTSTART;VALUE=DATE-TIME:20210331T124500Z
DTEND;VALUE=DATE-TIME:20210331T130000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5243@indico.math.cnrs.fr
DESCRIPTION:Speakers: Oliver Gould (University of Nottingham)\nA first-ord
er phase transition in the early universe would have given rise to a stoch
astic gravitational wave background which may be observable today. Startin
g from a particle physics Lagrangian\, the first step in making prediction
s of the gravitational wave signal is to understand the thermodynamics of
the phase transition. In this talk\, I will discuss the current situation
regarding the theory of the thermodynamics of cosmological phase transitio
ns. In particular\, I will focus on the crucial problem of making reliable
predictions in the face of infrared Bose enhancements at high temperature
. Such enhancements lead to stronger effective couplings\, and consequentl
y to large theoretical uncertainties in perturbative calculations. I will
outline recent developments in overcoming these problems\, and will commen
t on open questions and future directions.\n\nhttps://indico.math.cnrs.fr/
event/5766/contributions/5243/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5243/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Probing the inflationary particle content with gravitational waves
DTSTART;VALUE=DATE-TIME:20210331T120000Z
DTEND;VALUE=DATE-TIME:20210331T121500Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5244@indico.math.cnrs.fr
DESCRIPTION:Speakers: Matteo Fasiello (IFT UAM-CSIC\, Madrid)\nI will high
light the immense discovery potential on early universe physics stemming f
rom gravitational wave probes. To this aim\, I will survey two approaches
to inflation\, from the particular (axion inflation models) to the general
(an EFT approach).\nI will show how a characterisation of the GW signal t
hat includes (i) frequency profile\, (ii) chirality\, (iii) higher-point f
unctions\, (iv) anisotropies\, will deliver invaluable information on the
inflationary particle content.\nUpcoming gravitational wave probes hold th
e key to turn inflationary observables into a direct portal to high energy
physics.\n\nhttps://indico.math.cnrs.fr/event/5766/contributions/5244/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5244/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kination cosmology from scalar fields and gravitational-wave signa
tures
DTSTART;VALUE=DATE-TIME:20210331T121500Z
DTEND;VALUE=DATE-TIME:20210331T123000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5241@indico.math.cnrs.fr
DESCRIPTION:Speakers: Peera Simakachorn (Universität Hamburg and DESY)\nA
scalar field with large kinetic energy can dominate the Universe at early
times and generates the so-called kination era. We present a natural and
well-motivated particle physics realization\, based simply on a Peccei-Qui
nn mechanism. The presence of kination imprints a smoking-gun spectral enh
ancement in the stochastic gravitational-wave (GW) background. Current and
future-planned GW observatories could constrain particle theories that ge
nerate the kination phase. This work explores kination from a complex scal
ar field responsible for spontaneous symmetry-breaking of a U(1)-symmetry
related to baryogenesis and axion physics. Surprisingly\, the viable param
eter space allows for a kination era at the TeV scale and generates a peak
ed spectrum of GW from either cosmic strings or primordial inflation\, whi
ch lies inside ET and CE windows.\n\nhttps://indico.math.cnrs.fr/event/576
6/contributions/5241/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5241/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gravitational radiation from MHD turbulence in the early universe
DTSTART;VALUE=DATE-TIME:20210331T123000Z
DTEND;VALUE=DATE-TIME:20210331T124500Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5238@indico.math.cnrs.fr
DESCRIPTION:Speakers: Alberto Roper Pol (APC)\nThe generation of primordia
l magnetic fields and its interaction with the primordial plasma during co
smological phase transitions is turbulent in nature. I will describe and d
iscuss results of direct numerical simulations of magnetohydrodynamic (MHD
) turbulence in the early universe and the resulting stochastic gravitatio
nal wave background (SGWB). In addition to the SGWB\, the primordial magne
tic field will evolve up to our present time and its relics can explain in
direct observations of weak magnetic fields coherent on very large scales.
I will apply the numerical results to magnetic fields produced at the ele
ctroweak and the QCD phase transitions and show that these signals may be
detectable by the planned Laser Interferometer Space Antenna and by Pulsar
Timing Array. The detection of these signals would lead to the understand
ing of cosmological phase transition physics\, which can have consequences
on the baryon asymmetry problem and on the origin seed of observed magnet
ic fields coherent over very large scales at the present time.\n\nhttps://
indico.math.cnrs.fr/event/5766/contributions/5238/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5238/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Influence of the crust on neutron star macrophysical quantities an
d universal relations
DTSTART;VALUE=DATE-TIME:20210330T144500Z
DTEND;VALUE=DATE-TIME:20210330T150000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5237@indico.math.cnrs.fr
DESCRIPTION:Speakers: Lami Suleiman (Laboratoire Univers et Théories et C
entre d'Astronomie Nicolas Copernic (Pologne))\nMeasurements of neutron st
ar macrophysical properties thanks to multi-messenger observations offer t
he possibility to constrain the properties of nuclear matter. Indeed cold
and dense matter as found inside neutron stars\, in particular in their co
re\, is not accessible to terrestrial laboratories.\n\nWe investigate the
consequences of using equations of state that employ models for the core a
nd the crust that are not calculated consistently on the neutron star macr
ophysical properties\, on some of the so-called universal relations and on
the constraints obtained from gravitational wave observations. Various tr
eatments found in the literature are used to connect together non-consiste
nt core and crust equations of state. We assess the discrepancies in the n
eutron star macrophysical properties obtained when consistent models for t
he whole star and non-consistent ones are employed.\n\nThe use of crust mo
dels non consistent with the core introduces an error on the macrophysical
parameters which can be as large as the estimated accuracy of current and
next generation telescopes. The precision of some of the universal relati
ons reported in the literature is found to be overestimated. We confirm th
at the equation of the crust has limited influence on the macrophysical pr
operties.\n\nhttps://indico.math.cnrs.fr/event/5766/contributions/5237/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5237/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gravitational wave signature of proto-neutron star convection
DTSTART;VALUE=DATE-TIME:20210330T143000Z
DTEND;VALUE=DATE-TIME:20210330T144500Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5236@indico.math.cnrs.fr
DESCRIPTION:Speakers: Raphaël Raynaud (CEA Saclay)\nGravitational waves p
rovide a unique opportunity to better constrain the dynamics in the interi
or of proto-neutron stars during core collapse supernovae. Convective moti
ons inside the proto-neutron star play an important role in determining ne
utron star magnetic fields. In paticular\, numerical models suggest that a
convective dynamo could explain magnetar formation in presence of fast ro
tation. Using 3D MHD simulations of proto-neutron star convective zones\,
we compute the gravitational wave emission from turbulent convection and s
tudy the impacts of both rotation and dynamo action. We derive physical sc
alings that reproduce quantitatively several aspects of the numerical resu
lts. Given the potentially long duration of the signal\, we find that the
typical strain and frequency range could allow its detection by current GW
detectors in a nearby supernova explosion\, and may be a primary target f
or next generation of GW detectors. In some cases\, the signal may even ca
pture the growth of a magnetic field due to dynamo action.\n\nhttps://indi
co.math.cnrs.fr/event/5766/contributions/5236/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5236/
END:VEVENT
BEGIN:VEVENT
SUMMARY:What can be learned from a proto-neutron star's mass and radius ?
DTSTART;VALUE=DATE-TIME:20210330T134500Z
DTEND;VALUE=DATE-TIME:20210330T140000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5235@indico.math.cnrs.fr
DESCRIPTION:Speakers: Edwan PREAU (APC)\nWe make extensive numerical studi
es of masses and radii of proto-neutron stars during the first second afte
r their birth in core-collapse supernova events. We use a quasi-static app
roach for the computation of proto-neutron star structure\, built on param
eterized entropy and electron fraction profiles\, that are then evolved wi
th neutrino cooling processes. We vary the equation of state of nuclear ma
tter\, the proto-neutron star mass and the parameters of the initial profi
les\, to take into account our ignorance of the supernova progenitor prope
rties. We show that if masses and radii of a proto-neutron star can be det
ermined in the first second after the birth\, e.g. from gravitational wave
emission\, no information could be obtained on the corresponding cold neu
tron star and therefore on the cold nuclear equation of state. Similarly\,
it seems unlikely that any property of the proto-neutron star equation of
state (hot and not beta-equilibrated) could be determined either\, mostly
due to the lack of information on the entropy\, or equivalently temperatu
re\, distribution in such objects.\n\nhttps://indico.math.cnrs.fr/event/57
66/contributions/5235/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5235/
END:VEVENT
BEGIN:VEVENT
SUMMARY:GW190814: On the properties of the secondary component of the bina
ry
DTSTART;VALUE=DATE-TIME:20210330T133000Z
DTEND;VALUE=DATE-TIME:20210330T134500Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5240@indico.math.cnrs.fr
DESCRIPTION:Speakers: BHASKAR BISWAS (IUCAA\, Pune )\nWe show that the od
ds of the mass-gap (secondary) object in GW190814 being a neutron star (NS
) improve if one allows for a stiff high-density equation of state (EoS) o
r a large spin. Since its mass is $\\in (2.50\,2.67) M_{\\odot}$\, establi
shing its true nature will make it either the heaviest NS or the lightest
black hole (BH)\, and can have far-reaching implications on NS EoS and com
pact object formation channels. When limiting oneself to the NS hypothesis
\, we deduce the secondary's properties by using a Bayesian framework with
a hybrid EoS formulation that employs a parabolic expansion-based nuclea
r empirical parameterization around the nuclear saturation density augment
ed by a generic 3-segment piecewise polytrope (PP) model at higher densiti
es and combining a variety of astrophysical observations. For the slow-ro
tation scenario\, GW190814 implies a very stiff EoS and a stringent constr
aint on the EoS specially in the high-density region. On the other hand a
ssuming the secondary object is a rapidly rotating NS\, we constrain its r
otational frequency to be $f=1170^{+389}_{-495}$ Hz\, within a $90\\%$ con
fidence interval. In this scenario\, the secondary object in GW190814 woul
d qualify as the fastest rotating NS ever observed. However\, for this sc
enario to be viable\, rotational instabilities would have to be suppressed
both during formation and the subsequent evolution until merger\, otherwi
se the secondary of GW190814 is more likely to be a BH.\n\nhttps://indico.
math.cnrs.fr/event/5766/contributions/5240/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5240/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rapid Identification of continuous gravitational-wave signals
DTSTART;VALUE=DATE-TIME:20210330T131500Z
DTEND;VALUE=DATE-TIME:20210330T133000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5250@indico.math.cnrs.fr
DESCRIPTION:Speakers: Iuri La Rosa (LAPP\, CNRS\, La Sapienza)\nContinuous
gravitational waves (CWs) from asymmetric spinning neutron stars are amon
g the most interesting\, although still undetected\, targets of the Advanc
ed LIGO-Virgo detectors. The search for this class of signals is difficult
due to their expected weakness\, and can be very computationally expensiv
e when the source parameters are not known.\nThe stochastic group uses fas
t and consolidated cross-correlation techniques to search for either a sto
chastic background of gravitational waves (SGWB) or persistent gravitation
al waves in specific directions. Recent investigations have shown that sto
chastic directional searches have the ability to detect CWs as well\, with
less sensitivity than CWs searches\, but with low computing requirements.
\nWe present a joint SGWB-CW pipeline chain that uses the robustness of SG
WB cross-correlation algorithms to quickly identify CW signals\, and the a
ccuracy of CW matched-filtering-based codes to properly follow up interest
ing CW candidates.\n\nhttps://indico.math.cnrs.fr/event/5766/contributions
/5250/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5250/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Localizing massive binary black holes with LISA
DTSTART;VALUE=DATE-TIME:20210330T130000Z
DTEND;VALUE=DATE-TIME:20210330T131500Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5267@indico.math.cnrs.fr
DESCRIPTION:Speakers: Sylvain Marsat (APC)\nLISA is a future space-based g
ravitational wave detector that will a new window into the gravitational u
niverse in the mHz range. Among LISA targets\, coalescences of massive bla
ck hole binaries (MBHB) will be detected with unprecedented signal-to-nois
e ratios\, and might enable multimessenger observations with instruments s
uch as Athena\, LSST and SKA. Modelling LISA's ability to locate these MBH
B signals\, both during their inspiral and after coalescence\, is crucial
to understand this synergy. We investigate this question using tools for B
ayesian inference that allow to go beyond Fisher-matrix based estimates. W
e highlight the role of higher harmonics in the signal as well as the role
of the time- and frquency-dependency in the instrumental response in brea
king degeneracies in parameter space\, and discuss the occurence of multim
odalities in the recovered sky position.\n\nhttps://indico.math.cnrs.fr/ev
ent/5766/contributions/5267/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5267/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sparse Data Inpainting for LISA gapped data
DTSTART;VALUE=DATE-TIME:20210330T124500Z
DTEND;VALUE=DATE-TIME:20210330T130000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5268@indico.math.cnrs.fr
DESCRIPTION:Speakers: Aurore Blelly (CEA/IRFU)\nWith LISA mission\, the de
tection of galactic binaries as sources of gravitational waves promises an
unprecedented wealth of information about these systems\, but also raises
several challenges in signal processing. In particular\, the variety of s
ources and the presence of both planned and unplanned gaps call for the de
velopment of robust methods. We describe here an original non-parametric j
oint reconstruction (data inpainting) of both the imprint of galactic bina
ries and adequate instrumental noise in the data gaps. We carefully show
that a sparse data representation gives a reliable access to the physical
content of the interferometric measurement\, even when the data is gapped\
, and that the recovered noise distribution matches with the expected nois
e distribution for LISA. \nWe demonstrate the successful data recovery on
a simple yet realistic example involving verification galactic binaries re
cently proposed in LISA data challenges. We also propose a first assessmen
t of the impact of gaps on LISA data.\n\nhttps://indico.math.cnrs.fr/event
/5766/contributions/5268/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5268/
END:VEVENT
BEGIN:VEVENT
SUMMARY:It takes two (spins) to tango: Interpreting gravitational-wave dat
a with a generalized effective precession parameter
DTSTART;VALUE=DATE-TIME:20210330T123000Z
DTEND;VALUE=DATE-TIME:20210330T124500Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5251@indico.math.cnrs.fr
DESCRIPTION:Speakers: Matthew Mould ()\nCurrent gravitational-wave data an
alysis of merging binary black holes accounts for two precessing spins\, a
llowing inference of the six spin degrees of freedom. Nonetheless\, it is
convenient to use effective parameters to interpret detections\; the effec
tive aligned spin $\\chi_{\\rm{eff}}$ and the effective precessing spin $\
\chi_{\\rm{p}}$ measure components parallel and perpendicular to the orbit
al angular momentum\, with measurements away from zero indicating large sp
ins and significant precession\, respectively. While the aligned spin is c
onserved during an inspiral\, the precessing spin is not\; furthermore\, i
ts definition employs a single-spin approximation that retains some\, but
not all\, precession-timescale variations. To rectify this inconsistency\,
we propose two-spin definitions that either fully consider or fully avera
ge those variations. The generalized parameter presents an exclusive regio
n\, $1\\leq\\chi_{\\rm{p}}\\leq2$\, accessible only to binaries with two p
recessing spins. For current LIGO/Virgo events\, our generalized parameter
indicates that\, while (i) previous measurement errors on the effective p
recessing spin may be underestimated\, (ii) the evidence for spin precessi
on may be stronger than suggested previously.\n\nhttps://indico.math.cnrs.
fr/event/5766/contributions/5251/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5251/
END:VEVENT
BEGIN:VEVENT
SUMMARY:DeepHMC: a deep neural network enhanced Hamiltonian Monte Carlo al
gorithm for accelerated Bayesian inference of binary neutron star paramete
rs
DTSTART;VALUE=DATE-TIME:20210330T121500Z
DTEND;VALUE=DATE-TIME:20210330T123000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5249@indico.math.cnrs.fr
DESCRIPTION:Speakers: Marc Arène (APC)\nA major activity of the LIGO-Virg
o-KAGRA collaboration is to build algorithms able to infer from the detect
ed gravitational wave signals the posterior distributions of the parameter
s defining their sources: angles in the sky\, distance from us\, masses et
c. Current algorithms like MCMC and Nested Sampling have already demonstra
ted with success their ability to do so during the first three runs of obs
ervations of the detectors.\n\nNonetheless the latter remain computational
ly expensive as they require from weeks to months of CPU time when analyzi
ng long duration signals\, typically BNS ones\, and when using advanced wa
veform models.\nAs the sensitivity of GW interferometers is being improved
years after years\, the duration of exploitable signal and rate of detect
ion increase ($10^{+52}_{-10}\\\,\\text{y}^{-1}$ BNS expected during O4)\,
requiring more and longer analysis which creates an important tension wit
h the time required to perform each of them.\n\nTo respond to this challen
ge we will present DeepHMC\, a Hamiltonian Monte Carlo (HMC) algorithm boo
sted by a Deep Neural Network (DNN).\nContrary to currently used algorithm
s\, the HMC is a non random-walk sampler as it uses the gradient of the po
sterior distribution to make new chain proposals\, making it more efficien
t than MCMC or Nested Sampling.\nTo circumvent the computational bottlenec
k of numerical gradients which require many waveform generations and preve
nted an earlier use of the HMC\, we train a DNN to predict gradients at ne
w points in parameter space.\nTested on the BNS GW170817\, we compare Deep
HMC's results with those produced by LALInferenceMCMC and show that DeepHM
C is ~80 times faster.\n\nhttps://indico.math.cnrs.fr/event/5766/contribut
ions/5249/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5249/
END:VEVENT
BEGIN:VEVENT
SUMMARY:GPE: GPU-accelerated parameter estimation for gravitational waves
DTSTART;VALUE=DATE-TIME:20210330T120000Z
DTEND;VALUE=DATE-TIME:20210330T121500Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5248@indico.math.cnrs.fr
DESCRIPTION:Speakers: Yun-Jing Huang (Academia Sinica\, Taiwan)\nWe presen
t GPE\, a GPU-accelerated parameter estimation package for gravitational w
aves from compact binary coalescence sources. This stand-alone program is
adapted from the nested sampling flavor of LALInference. Two main parallel
ization methods are implemented: (1) the frequency-domain waveform and lik
elihood calculations\, (2) and the prior sampling portion in the nested sa
mpling algorithm. We show that GPE can produce consistent results compared
to LALInference\, while demonstrating a 200-400 times speedup on one GPU
compared to LALInference on one CPU. The high acceleration of GPE can faci
litate the data-analysis of detected events\, simulations for detector obs
erving scenarios\, and production of sky localization regions for EM follo
w-up.\n\nhttps://indico.math.cnrs.fr/event/5766/contributions/5248/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5248/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gravitational Bremsstrahlung in the Post-Minkowskian Effective Fie
ld Theory
DTSTART;VALUE=DATE-TIME:20210330T081500Z
DTEND;VALUE=DATE-TIME:20210330T083000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5247@indico.math.cnrs.fr
DESCRIPTION:Speakers: Massimiliano Maria Riva ()\nWe study the gravitation
al radiation emitted during the scattering of two spinless bodies in the p
ost-Minkowskian Effective Field Theory approach. We derive the conserved s
tress-energy tensor linearly coupled to gravity and the classical probabil
ity amplitude of graviton emission at leading and next-to-leading order in
the Newton’s constant $G$. The amplitude can be expressed in compact\nf
orm as one-dimensional integrals over a Feynman parameter involving Bessel
functions. We use it to recover the leading-order radiated angular moment
um. Upon expanding it in the relative velocity between the two bodies $v$\
, we compute the total four-momentum radiated into gravitational waves at
leading-order in $G$ and up to order $v$ 8\, finding agreement with what r
ecently computed using scattering amplitude methods. Our results also allo
w to investigate the zero frequency limit of the emitted energy spectrum.\
n\nhttps://indico.math.cnrs.fr/event/5766/contributions/5247/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5247/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Schwarzschild-Tangherlini metric from scattering amplitudes in var
ious dimensions
DTSTART;VALUE=DATE-TIME:20210330T080000Z
DTEND;VALUE=DATE-TIME:20210330T081500Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5259@indico.math.cnrs.fr
DESCRIPTION:Speakers: Stavros Mougiakakos (IPhT\,CEA-Saclay)\nWe derive th
e static Schwarzschild-Tangherlini metric by extracting the classical cont
ributions from the multiloop vertex functions of a graviton emitted from a
massive scalar field. At each loop order the classical contribution is pr
oportional to a unique master integral given by the massless sunset integr
al. By computing the scattering amplitudes up to three-loop order in gener
al dimension\, we explicitly derive the expansion of the metric up to the
fourth post-Minkowskian order O(GN4) in four\, five and six dimensions. Th
ere are ultraviolet divergences that are cancelled with the introduction o
f higher-derivative nonminimal couplings. The standard Schwarzschild-Tangh
erlini is recovered by absorbing their effects by an appropriate coordinat
e transformation induced from the de Donder gauge condition.\n\nhttps://in
dico.math.cnrs.fr/event/5766/contributions/5259/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5259/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Spinning black holes fall in Love
DTSTART;VALUE=DATE-TIME:20210330T073000Z
DTEND;VALUE=DATE-TIME:20210330T074500Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5260@indico.math.cnrs.fr
DESCRIPTION:Speakers: Alexandre Le Tiec (Observatoire de Paris)\nThe open
question of whether a black hole can become tidally deformed by an externa
l gravitational field has profound implications for fundamental physics\,
astrophysics and gravitational-wave astronomy. Love tensors characterize t
he tidal deformability of compact objects such as astrophysical (Kerr) bla
ck holes under an external static tidal field. We prove that all Love tens
ors vanish identically for a Kerr black hole in the nonspinning limit or f
or an axisymmetric tidal perturbation. In contrast to this result\, we sho
w that Love tensors are generically nonzero for a spinning black hole. Spe
cifically\, to linear order in the Kerr black hole spin and the weak pertu
rbing tidal field\, we compute in closed form the Love tensors that couple
the mass-type and current-type quadrupole moments to the electric-type an
d magnetic-type quadrupolar tidal fields. For a dimensionless spin ~ 0.1\,
the nonvanishing quadrupolar Love tensors are ~ 0.002\, thus showing that
black holes are particularly "rigid" compact objects.\n\nhttps://indico.m
ath.cnrs.fr/event/5766/contributions/5260/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5260/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Primordial Black Holes and Cosmological Gravitational Waves
DTSTART;VALUE=DATE-TIME:20210330T070000Z
DTEND;VALUE=DATE-TIME:20210330T073000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5138@indico.math.cnrs.fr
DESCRIPTION:Speakers: Misao Sasaki (IPMU)\nhttps://indico.math.cnrs.fr/eve
nt/5766/contributions/5138/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5138/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Expected properties of electromagnetic counterparts of BHNS merger
s
DTSTART;VALUE=DATE-TIME:20210330T090000Z
DTEND;VALUE=DATE-TIME:20210330T093000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5141@indico.math.cnrs.fr
DESCRIPTION:Speakers: Giancarlo Ghirlanda ()\nhttps://indico.math.cnrs.fr/
event/5766/contributions/5141/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5141/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Probing subatomic physics with gravitational waves from neutron st
ar binary inspirals
DTSTART;VALUE=DATE-TIME:20210330T093000Z
DTEND;VALUE=DATE-TIME:20210330T100000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5142@indico.math.cnrs.fr
DESCRIPTION:Speakers: Tania Hinderer ()\nhttps://indico.math.cnrs.fr/event
/5766/contributions/5142/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5142/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Multimessenger astronomy with massive black hole binaries
DTSTART;VALUE=DATE-TIME:20210330T100000Z
DTEND;VALUE=DATE-TIME:20210330T103000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5143@indico.math.cnrs.fr
DESCRIPTION:Speakers: Alberto Sesana ()\nhttps://indico.math.cnrs.fr/event
/5766/contributions/5143/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5143/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Minimalism in modified gravity
DTSTART;VALUE=DATE-TIME:20210331T070000Z
DTEND;VALUE=DATE-TIME:20210331T073000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5147@indico.math.cnrs.fr
DESCRIPTION:Speakers: Shinji Mukohyama ()\nhttps://indico.math.cnrs.fr/eve
nt/5766/contributions/5147/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5147/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Flexible analysis of gravitational wave data: signal polarization
and detector glitches
DTSTART;VALUE=DATE-TIME:20210330T153000Z
DTEND;VALUE=DATE-TIME:20210330T160000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5146@indico.math.cnrs.fr
DESCRIPTION:Speakers: Katerina Chatzioannou ()\nhttps://indico.math.cnrs.f
r/event/5766/contributions/5146/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5146/
END:VEVENT
BEGIN:VEVENT
SUMMARY:From Amplitudes to Waveforms
DTSTART;VALUE=DATE-TIME:20210331T080000Z
DTEND;VALUE=DATE-TIME:20210331T083000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5149@indico.math.cnrs.fr
DESCRIPTION:Speakers: David Kosower ()\nhttps://indico.math.cnrs.fr/event/
5766/contributions/5149/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5149/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Testing strong gravity with quasi-normal-modes
DTSTART;VALUE=DATE-TIME:20210331T090000Z
DTEND;VALUE=DATE-TIME:20210331T093000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5151@indico.math.cnrs.fr
DESCRIPTION:Speakers: Sweta Bhagwat ()\nQuasinormal modes in the ringdowns
are powerful probes for testing the behaviour of strong-field gravity aro
und the black holes. In this talk\, first\, I want to quickly review the t
ests of gravity that are being done using the binary black-hole quasi-norm
al modes currently. Then I will discuss some possible tests of gravity tha
t can be performed using the next-generation detectors using the quasi-nor
mal modes.\n\nhttps://indico.math.cnrs.fr/event/5766/contributions/5151/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5151/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gravitational waves as probe of the very early universe
DTSTART;VALUE=DATE-TIME:20210331T093000Z
DTEND;VALUE=DATE-TIME:20210331T100000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5152@indico.math.cnrs.fr
DESCRIPTION:Speakers: Valerie Domcke ()\nhttps://indico.math.cnrs.fr/event
/5766/contributions/5152/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5152/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Primordial Nano Black Holes
DTSTART;VALUE=DATE-TIME:20210331T100000Z
DTEND;VALUE=DATE-TIME:20210331T103000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5153@indico.math.cnrs.fr
DESCRIPTION:Speakers: Antonio Riotto ()\nhttps://indico.math.cnrs.fr/event
/5766/contributions/5153/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5153/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Quantum noise in interferometric gravitational-wave detectors
DTSTART;VALUE=DATE-TIME:20210331T143000Z
DTEND;VALUE=DATE-TIME:20210331T150000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5155@indico.math.cnrs.fr
DESCRIPTION:Speakers: Eleonora Capocasa ()\nhttps://indico.math.cnrs.fr/ev
ent/5766/contributions/5155/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5155/
END:VEVENT
BEGIN:VEVENT
SUMMARY:A global perspective on LISA analysis and cosmological backgrounds
DTSTART;VALUE=DATE-TIME:20210331T150000Z
DTEND;VALUE=DATE-TIME:20210331T153000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5156@indico.math.cnrs.fr
DESCRIPTION:Speakers: Neil Cornish ()\nhttps://indico.math.cnrs.fr/event/5
766/contributions/5156/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5156/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gravitational-wave background mapping: investigations in LIGO and
prospects for LISA
DTSTART;VALUE=DATE-TIME:20210331T153000Z
DTEND;VALUE=DATE-TIME:20210331T160000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5157@indico.math.cnrs.fr
DESCRIPTION:Speakers: Arianna Renzini ()\nhttps://indico.math.cnrs.fr/even
t/5766/contributions/5157/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5157/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lessons on the equation of state from binary neutron stars
DTSTART;VALUE=DATE-TIME:20210401T090000Z
DTEND;VALUE=DATE-TIME:20210401T093000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5159@indico.math.cnrs.fr
DESCRIPTION:Speakers: Luciano Rezzolla ()\nhttps://indico.math.cnrs.fr/eve
nt/5766/contributions/5159/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5159/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Einstein Telescope
DTSTART;VALUE=DATE-TIME:20210401T100000Z
DTEND;VALUE=DATE-TIME:20210401T101500Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5279@indico.math.cnrs.fr
DESCRIPTION:Speakers: Edward Porter ()\nhttps://indico.math.cnrs.fr/event/
5766/contributions/5279/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5279/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Perturbing binary black holes with effective field theory
DTSTART;VALUE=DATE-TIME:20210401T134500Z
DTEND;VALUE=DATE-TIME:20210401T140000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5266@indico.math.cnrs.fr
DESCRIPTION:Speakers: Leong Khim Wong ()\nEffective field theories (EFTs)
facilitate what might otherwise be completely untenable calculations by he
lping us focus on only the most relevant physics at hand. Applied to gener
al relativity\, these techniques have famously improved our handle on post
-Newtonian theory over the last decade\, and extensions of these ideas are
now also being developed to study how binary systems evolve when they are
not isolated in empty space but subjected to external perturbations. One
scenario of particular interest is the “gravitational molecule\,” wher
ein a light bosonic field (like a string-theory axion) forms a cloud that
is gravitationally bound to a binary black hole. In this talk\, I will ske
tch how an EFT allows us to solve for the evolution of this system analyti
cally (under certain approximations)\, and will discuss a number of its ke
y predictions: beating patterns\, a partial upscattering of the cloud into
radiation\, and a novel guise of superradiance.\n\nhttps://indico.math.cn
rs.fr/event/5766/contributions/5266/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5266/
END:VEVENT
BEGIN:VEVENT
SUMMARY:The onset of spontaneous scalarization in generalised scalar-tenso
r theories
DTSTART;VALUE=DATE-TIME:20210401T133000Z
DTEND;VALUE=DATE-TIME:20210401T134500Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5265@indico.math.cnrs.fr
DESCRIPTION:Speakers: Giulia Ventagli (University of Nottingham)\nIn gravi
ty theories that exhibit spontaneous scalarization\, astrophysical objects
are identical to their general relativistic counterpart until they reach
a certain threshold in compactness or curvature. Beyond this threshold\, t
hey acquire a non-trivial scalar configuration\, which also affects their
structure. The onset of scalarization is controlled only by terms that con
tribute to linear perturbation around solutions of general relativity. The
complete set of these terms has been identified for generalized scalar-te
nsor theories. Stepping on this result\, we study the onset on scalarizati
on in generalized scalar-tensor theories and determine the relevant thresh
olds in terms of the contributing coupling constants and the properties of
the compact object.\n\nhttps://indico.math.cnrs.fr/event/5766/contributio
ns/5265/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5265/
END:VEVENT
BEGIN:VEVENT
SUMMARY:How does a dark compact object ringdown?
DTSTART;VALUE=DATE-TIME:20210401T131500Z
DTEND;VALUE=DATE-TIME:20210401T133000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5264@indico.math.cnrs.fr
DESCRIPTION:Speakers: Elisa Maggio (Sapienza University of Rome)\nGravitat
ional waves from the coalescence of compact binaries provide a unique oppo
rtunity to test gravity in strong field regime. In particular\, the postme
rger phase of the gravitational signal is a proxy for the nature of the re
mnant.\nThis is of particular interest in view of some quantum-gravity mod
els which predict the existence of horizonless compact objects that overco
me the paradoxes associated to black holes. Such dark compact objects can
emit a modified ringdown with respect to the black hole case and late-time
gravitational wave echoes as characteristic fingerprints.\nIn this talk\,
I develop a generic framework to the study of the ringdown of dark compac
t objects and provide a gravitational-wave template for the echo signal. F
inally\, I assess the detectability of dark compact objects with current a
nd future gravitational-wave detectors.\n\nhttps://indico.math.cnrs.fr/eve
nt/5766/contributions/5264/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5264/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Metric reconstruction with gravitational waves and shadows
DTSTART;VALUE=DATE-TIME:20210401T130000Z
DTEND;VALUE=DATE-TIME:20210401T131500Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5263@indico.math.cnrs.fr
DESCRIPTION:Speakers: Sebastian Völkel (SISSA and IFPU\, Trieste\, Italy)
\nIn this talk I present three recent works [1\,2\,3] that aim to enhance
our understanding of reconstructing black hole space-times from different
type of observations. While gravitational wave detectors like LIGO/Virgo a
llow to perform black hole spectroscopy of stellar mass black holes\, imag
es such as those produced by the Event Horizon Telescope provide informati
on of the shadow from super massive black holes. A theory agnostic approac
h starting from a parametrized metric is combined with Bayesian analysis t
o infer possible metric deviations from simulated quasi-normal modes\, as
well as from the observed size of the shadow of M87*. It is demonstrated u
nder what simplifying assumptions both type of inverse problems can be stu
died\, as well as what conceptual difficulties arise in a theory agnostic
approach. Finally\, it is highlighted how both type of observations are co
mplementary to each other and how consistent calculations for parametrized
metrics can be done in alternative theories of gravity.\n\n[1] Bayesian M
etric Reconstruction with Gravitational Wave Observations\, Sebastian H. V
ölkel and Enrico Barausse\, Phys. Rev. D 102\, 084025\, 2020\, https://ar
xiv.org/abs/2007.02986\n\n[2] EHT tests of the strong-field regime of Gene
ral Relativity\, Sebastian H. Völkel\, Enrico Barausse\, Nicola Franchini
and Avery E. Broderick\, in review\, https://arxiv.org/abs/2011.06812\n\n
[3] An exact theory for the Rezzolla-Zhidenko metric and self-consistent c
alculation of quasi-normal modes\, Arthur G. Suvorov and Sebastian H. Völ
kel\, Phys. Rev. D 103\, 044027\, 2021\, https://arxiv.org/abs/2101.09697\
n\nhttps://indico.math.cnrs.fr/event/5766/contributions/5263/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5263/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Detecting scalar field with extreme mass ratio inspirals
DTSTART;VALUE=DATE-TIME:20210401T124500Z
DTEND;VALUE=DATE-TIME:20210401T130000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5262@indico.math.cnrs.fr
DESCRIPTION:Speakers: Nicola Franchini (Sissa)\nI will present extreme mas
s ratio inspirals (EMRIs)\, during which a small body spirals into a super
massive black hole\, in gravity theories with additional scalar fields. No
-hair theorems and properties of known theories that manage to circumvent
them introduce a drastic simplification to the problem: the effects of the
scalar on supermassive black holes\, if any\, are mostly negligible for E
MRIs in vast classes of theories. I will show how to exploit this simplifi
cation to model the inspiral perturbatively and demonstrate that the scala
r charge of the small body leaves a significant imprint on gravitational w
ave emission. This result is particularly appealing\, as this imprint is o
bservable with LISA\, rendering EMRIs promising probes of scalar fields.\n
\nhttps://indico.math.cnrs.fr/event/5766/contributions/5262/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5262/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Some recent results in GW astrophysics
DTSTART;VALUE=DATE-TIME:20210401T143000Z
DTEND;VALUE=DATE-TIME:20210401T150000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5163@indico.math.cnrs.fr
DESCRIPTION:Speakers: Daniel Holz ()\nhttps://indico.math.cnrs.fr/event/57
66/contributions/5163/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5163/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Some thoughts on the properties of the population of BBH mergers
DTSTART;VALUE=DATE-TIME:20210401T150000Z
DTEND;VALUE=DATE-TIME:20210401T153000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5164@indico.math.cnrs.fr
DESCRIPTION:Speakers: Matias Zaldarriaga ()\nhttps://indico.math.cnrs.fr/e
vent/5766/contributions/5164/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5164/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Prospects for the future of gravitational-wave observation
DTSTART;VALUE=DATE-TIME:20210401T153000Z
DTEND;VALUE=DATE-TIME:20210401T160000Z
DTSTAMP;VALUE=DATE-TIME:20220816T073547Z
UID:indico-contribution-5766-5165@indico.math.cnrs.fr
DESCRIPTION:Speakers: David Shoemaker ()\nhttps://indico.math.cnrs.fr/even
t/5766/contributions/5165/
LOCATION:
URL:https://indico.math.cnrs.fr/event/5766/contributions/5165/
END:VEVENT
END:VCALENDAR