arXiv subjects

Eric Chassande-Mottin

Publications and source records attributed to Eric Chassande-Mottin.

16 recordsLinked to original sources

arXiv2026

GRINTA: a new Probe of the Dynamic Universe

Recent observations of the transient sky at all wavelengths are increasingly revealing the importance of the multi-messenger and multi-wavelength approach. The GRINTA (Gamma-Ray INternational Transient Array Observatory) mission, proposed for launch around the middle of the next decade, is conceived as a small mission with good sensitivity, excellent angular resolution and fast follow-up capability for studying transient sources at timescales from ms to hours, at the same time ensuring optimal integration with multi-messenger networks. The GRINTA mission will carry two complementary payloads to cover in total the 5 keV-10 MeV band, that will detect and localise gamma-ray bursts covering $\sim$ half of the sky and will be able to perform imaging surveys with sub-arcmin resolution. GRINTA will operate in synergy with the most powerful electromagnetic, gravitational wave and neutrino observatories foreseen to be operational after 2035.

astro-ph.IM↗

arXiv2022

Current and future constraints on cosmology and modified gravitational wave friction from binary black holes

Gravitational wave (GW) standard sirens are well-established probes with which one can measure cosmological parameters, and are complementary to other probes like the cosmic microwave background or supernovae standard candles. Here we focus on dark GW sirens, specifically binary black holes (BBHs) for which there is only GW data. Our approach relies on the assumption of a source frame mass model for the BBH distribution, and we consider four models that are representative of the BBH population observed so far. In addition to inferring cosmological and mass model parameters, we use dark sirens to test modified gravity theories. These theories often predict different GW propagation equations on cosmological scales, leading to a different GW luminosity distance which in some cases can be parametrized by variables $Ξ_0$ and $n$. General relativity (GR) corresponds to $Ξ_0= 1$. We perform a joint estimate of the population parameters governing mass, redshift, the variables characterizing the cosmology, and the modified GW luminosity distance. We use data from the third LVK observation run and find - for the four mass models and for three SNR cuts - that GR is consistently the preferred model to describe all observed BBH GW signals. Furthermore, all modified gravity parameters have posteriors that are compatible with the values predicted by GR at the 90% confidence interval. We show that there are strong correlations between cosmological, astrophysical and modified gravity parameters. If GR is the correct theory of gravity, and assuming narrow priors on the cosmological parameters, we forecast an uncertainty of the modified gravity parameter $Ξ_0$ of 51% with $\sim 90$ detections at O4-like sensitivities, and $Ξ_0$ of 20% with an additional $\sim 400$ detections at O5-like sensitivity. We also consider how these forecasts depend on the current uncertainties of the BBH population.

gr-qc↗

arXiv2022

Constraints to neutron-star kicks in High-Mass X-ray Binaries with Gaia EDR3

All neutron star progenitors in neutron-star High-Mass X-ray Binaries (NS HMXBs) undergo a supernova event that may lead to a significant natal kick impacting the motion of the whole binary system. The space observatory Gaia performs a deep optical survey with exquisite astrometric accuracy, for both position and proper motions, that can be used to study natal kicks in NS HMXBs. We aim to survey the observed Galactic NS HMXB population and to quantify the magnitude of the kick imparted onto their NSs, and to highlight any possible differences arising in between the various HMXB types. We perform a census of Galactic NS HMXBs and cross-match existing detections in X-rays, optical and infrared with the Gaia Early Data Release 3 database. We retrieve their parallaxes, proper motions, and radial velocities (when available), and perform a selection based on the quality of the parallax measurement. We then compute their peculiar velocities with respect to the rotating reference frame of the Milky Way, and including their respective masses and periods, we estimate their kick velocities through Markov Chain Monte Carlo simulations of the orbit undergoing a supernova event. We infer the posterior kick distributions of 35 NS HMXBs. After an inconclusive attempt at characterising the kick distributions with Maxwellian statistics, we find that the observed NS kicks are best reproduced by a Gamma distribution of mean $116^{+18}_{-15}$km.s$^{-1}$. We note that supergiant systems tend to have higher kick velocities than Be High-Mass X-ray Binaries. The peculiar velocity versus non-degenerate companion mass plane hints at a similar trend, supergiant systems having a higher peculiar velocity independently of their companion mass.

astro-ph.HE↗

arXiv2022

Current and future constraints on cosmology and modified gravitational wave friction from binary black holes

In this proceedings, we are interested in dark gravitational wave standard sirens and their use for cosmology and for constraining modified gravity theories. Due to the extra friction term introduced in their propagation equation those theories predict different luminosity distances for electromagnetic and gravitational waves (GWs). This effect can be parametrized by the two variables $Ξ_0$ and $n$, that can be measured from gravitational wave observations, and specifically from the binary black hole (BBH) mergers detected by LIGO and Virgo. By fitting jointly BBH population models in mass and redshift, the cosmological parameters, and the modified GW luminosity distance to $\sim$ 60 signals observed during the first three LIGO/Virgo observation runs, we conclude that general relativity is consistently the preferred model. The future observation runs O4 and O5 are also considered. Using the same approach, we forecast a measurement uncertainty on the modified gravity parameter $Ξ_0$ of $51\%$ with O4, and $20\%$ with O4 and O5, respectively if GR is the correct theory of gravity. However, we underline that there are strong correlations between astrophysical, cosmological and modified gravity parameters, possibly leading to bias if wrong priors are assumed.

gr-qc↗

arXiv2021

Progenitors of low-mass binary black-hole mergers in the isolated binary evolution scenario

We aim to study the progenitor properties and expected rates of the two lowest-mass binary black hole (BH) mergers, GW 151226 and GW 170608, detected within the first two Advanced LIGO-Virgo runs, in the context of the isolated binary-evolution scenario. We use the public MESA code, which we adapted to include BH formation and unstable mass transfer developed during a common-envelope (CE) phase. Using more than 60000 binary simulations, we explore a wide parameter space for initial stellar masses, separations, metallicities, and mass-transfer efficiencies. We obtain the expected distributions for the chirp mass, mass ratio, and merger time delay by accounting for the initial stellar binary distributions. Our simulations show that, while the progenitors we obtain are compatible over the entire range of explored metallicities, they show a strong dependence on the initial masses of the stars, according to stellar winds. All the progenitors follow a similar evolutionary path, starting from binaries with initial separations in the $30-200~R_\odot$ range, experiencing a stable mass transfer interaction before the formation of the first BH, and a second unstable mass-transfer episode leading to a CE ejection that occurs either when the secondary star crosses the Hertzsprung gap or when it is burning He in its core. The CE phase plays a fundamental role in the considered low-mass range: only progenitors experiencing such an unstable mass-transfer phase are able to merge in less than a Hubble time. We find integrated merger-rate densities in the range $0.2-5.0~{\rm yr}^{-1}~{\rm Gpc}^{-3}$ in the local Universe for the highest mass-transfer efficiencies explored. The highest rate densities lead to detection rates of $1.2-3.3~{\rm yr}^{-1}$, being compatible with the observed rates. A high CE-efficiency scenario with $α_{\rm CE}=2.0$ is favored when comparing with observations. ABRIDGED.

astro-ph.HE↗

arXiv2017

Wavelet graphs for the direct detection of gravitational waves

A second generation of gravitational wave detectors will soon come online with the objective of measuring for the first time the tiny gravitational signal from the coalescence of black hole and/or neutron star binaries. In this communication, we propose a new time-frequency search method alternative to matched filtering techniques that are usually employed to detect this signal. This method relies on a graph that encodes the time evolution of the signal and its variability by establishing links between coefficients in the multi-scale time-frequency decomposition of the data. We provide a proof of concept for this approach.

astro-ph.IM↗

arXiv2017

Where and when: optimal scheduling of the electromagnetic follow-up of gravitational-wave events based on counterpart lightcurve models

The electromagnetic (EM) follow-up of a gravitational wave (GW) event requires to scan a wide sky region, defined by the so called "skymap", for the detection and identification of a transient counterpart. We propose a novel method that exploits information encoded in the GW signal to construct a "detectability map", which represents the time-dependent ("when") probability to detect the transient at each position of the skymap ("where"). Focusing on the case of a neutron star binary inspiral, we model the associated short gamma-ray burst afterglow and macronova emission, using the probability distributions of binary parameters (sky position, distance, orbit inclination, mass ratio) extracted from the GW signal as inputs. The resulting family of possible lightcurves is the basis to construct the detectability map. As a practical example, we apply the method to a simulated GW signal produced by a neutron star merger at 75 Mpc whose localization uncertainty is very large (about 1500 square degrees). We construct observing strategies based on the detectability maps for optical, infrared and radio facilities, taking VST, VISTA and MeerKAT as prototypes. Assuming limiting fluxes of r ~ 24.5, J ~ 22.4 (AB magnitudes) and 500 uJy @ 1.4 GHz for ~ 1000 s of exposure each, the afterglow and macronova emissions are successfully detected with a minimum observing time of 7, 15 and 5 hours respectively.

astro-ph.HE↗

arXiv2013

Data analysis challenges in transient gravitational-wave astronomy

Gravitational waves are radiative solutions of space-time dynamics predicted by Einstein's theory of General Relativity. A world-wide array of large-scale and highly sensitive interferometric detectors constantly scrutinizes the geometry of the local space-time with the hope to detect deviations that would signal an impinging gravitational wave from a remote astrophysical source. Finding the rare and weak signature of gravitational waves buried in non-stationary and non-Gaussian instrument noise is a particularly challenging problem. We will give an overview of the data-analysis techniques and associated observational results obtained so far by Virgo (in Europe) and LIGO (in the US), along with the prospects offered by the up-coming advanced versions of those detectors.

gr-qc↗

arXiv2012

Multimessenger Science Reach and Analysis Method for Common Sources of Gravitational Waves and High-energy Neutrinos

We present the baseline multimessenger analysis method for the joint observations of gravitational waves (GW) and high-energy neutrinos (HEN), together with a detailed analysis of the expected science reach of the joint search. The analysis method combines data from GW and HEN detectors, and uses the blue-luminosity-weighted distribution of galaxies. We derive expected GW+HEN source rate upper limits for a wide range of source parameters covering several emission models. Using published sensitivities of externally triggered searches, we derive joint upper limit estimates both for the ongoing analysis with the initial LIGO-Virgo GW detectors with the partial IceCube detector (22 strings) HEN detector and for projected results to advanced LIGO-Virgo detectors with the completed IceCube (86 strings). We discuss the constraints these upper limits impose on some existing GW+HEN emission models.

astro-ph.HE↗

arXiv2011

Performance of a Chirplet-based analysis for gravitational waves from binary black hole mergers

The gravitational wave (GW) signature of a binary black hole (BBH) coalescence is characterized by rapid frequency evolution in the late inspiral and merger phases. For a system with total mass larger than 100 M_sun, ground based GW detectors are sensitive to the merger phase, and the in-band whitened waveform is a short-duration transient lasting about 10-30 ms. For a symmetric mass system with total mass between 10 and 100 M_sun, the detector is sensitive instead to the inspiral phase and the in-band signal has a longer duration, between 30 ms - 3 s. Omega is a search algorithm for GW bursts that, with the assumption of locally stationary frequency evolution, uses sine-Gaussian wavelets as a template bank to decompose interferometer strain data. The local stationarity of sine-Gaussians induces a performance loss for the detection of lower mass BBH signatures, due to the mismatch between template and signal. We present the performance of a modified version of the Omega algorithm, Chirplet Omega, which allows a linear variation of frequency, to target BBH coalescences. The use of Chirplet-like templates enhances the measured signal-to-noise ratio due to less mismatch between template and data, and increases the detectability of lower mass BBH coalescences. We present the results of a performance study of Chirplet Omega in colored Gaussian noise at initial LIGO sensitivity.

gr-qc↗

arXiv2011

Bounding the Time Delay between High-energy Neutrinos and Gravitational-wave Transients from Gamma-ray Bursts

We derive a conservative coincidence time window for joint searches of gravita-tional-wave (GW) transients and high-energy neutrinos (HENs, with energies above 100GeV), emitted by gamma-ray bursts (GRBs). The last are among the most interesting astrophysical sources for coincident detections with current and near-future detectors. We take into account a broad range of emission mechanisms. We take the upper limit of GRB durations as the 95% quantile of the T90's of GRBs observed by BATSE, obtaining a GRB duration upper limit of ~150s. Using published results on high-energy (>100MeV) photon light curves for 8 GRBs detected by Fermi LAT, we verify that most high-energy photons are expected to be observed within the first ~150s of the GRB. Taking into account the breakout-time of the relativistic jet produced by the central engine, we allow GW and HEN emission to begin up to 100s before the onset of observable gamma photon production. Using published precursor time differences, we calculate a time upper bound for precursor activity, obtaining that 95% of precursors occur within ~250s prior to the onset of the GRB. Taking the above different processes into account, we arrive at a time window of tHEN - tGW ~ [-500s,+500s]. Considering the above processes, an upper bound can also be determined for the expected time window of GW and/or HEN signals coincident with a detected GRB, tGW - tGRB ~ tHEN - tGRB ~ [-350s,+150s].

astro-ph.HE↗

arXiv2010

Detection of gravitational-wave bursts with chirplet-like template families

Gravitational Wave (GW) burst detection algorithms typically rely on the hypothesis that the burst signal is "locally stationary", that is it changes slowly with frequency. Under this assumption, the signal can be decomposed into a small number of wavelets with constant frequency. This justifies the use of a family of sine-Gaussian templates in the Omega pipeline, one of the algorithms used in LIGO-Virgo burst searches. However there are plausible scenarios where the burst frequency evolves rapidly, such as in the merger phase of a binary black hole and/or neutron star coalescence. In those cases, the local stationarity of sine-Gaussians induces performance losses, due to the mismatch between the template and the actual signal. We propose an extension of the Omega pipeline based on chirplet-like templates. Chirplets incorporate an additional parameter, the chirp rate, to control the frequency variation. In this paper, we show that the Omega pipeline can easily be extended to include a chirplet template bank. We illustrate the method on a simulated data set, with a family of phenomenological binary black-hole coalescence waveforms embedded into Gaussian LIGO/Virgo-like noise. Chirplet-like templates result in an enhancement of the measured signal-to-noise ratio.

gr-qc↗

arXiv2010

Multimessenger astronomy with the Einstein Telescope

Gravitational waves (GWs) are expected to play a crucial role in the development of multimessenger astrophysics. The combination of GW observations with other astrophysical triggers, such as from gamma-ray and X-ray satellites, optical/radio telescopes, and neutrino detectors allows us to decipher science that would otherwise be inaccessible. In this paper, we provide a broad review from the multimessenger perspective of the science reach offered by the third generation interferometric GW detectors and by the Einstein Telescope (ET) in particular. We focus on cosmic transients, and base our estimates on the results obtained by ET's predecessors GEO, LIGO, and Virgo.

gr-qc↗

arXiv2009

Sparse sky grid for the coherent detection of gravitational wave bursts

The gravitational wave detectors currently in operation perform the analysis of their scientific data jointly. Concerning the search for bursting sources, coherent data analysis methods have been shown to be more efficient. In the coherent approach, the data collected by the detectors are time-shifted and linearly combined so that the signatures received by each detector add up constructively (thus improving the resulting signal-to-noise ratio). This operation has to be performed over a sky grid (which determines the sky locations to be searched). A limitation of those pipelines is their large computing cost. One of the available degrees of freedom to reduce the cost is the choice of the sky grid. Ideally, the sky sampling scheme should adapt the angular resolution associated with the considered gravitational wave detector network. As the geometry of detector network is not regular (the detectors are not equally spaced and oriented), the angular resolution varies largely depending on the sky location. We propose here a procedure which designs sky grids that permit a complete sky coverage with a minimum number of vertices and thus adapt the local resolution.

gr-qc↗

arXiv2007

Best network chirplet-chain: Near-optimal coherent detection of unmodeled gravitation wave chirps with a network of detectors

The searches of impulsive gravitational waves (GW) in the data of the ground-based interferometers focus essentially on two types of waveforms: short unmodeled bursts and chirps from inspiralling compact binaries. There is room for other types of searches based on different models. Our objective is to fill this gap. More specifically, we are interested in GW chirps with an arbitrary phase/frequency vs. time evolution. These unmodeled GW chirps may be considered as the generic signature of orbiting/spinning sources. We expect quasi-periodic nature of the waveform to be preserved independent of the physics which governs the source motion. Several methods have been introduced to address the detection of unmodeled chirps using the data of a single detector. Those include the best chirplet chain (BCC) algorithm introduced by the authors. In the next years, several detectors will be in operation. The joint coherent analysis of GW by multiple detectors can improve the sight horizon, the estimation of the source location and the wave polarization angles. Here, we extend the BCC search to the multiple detector case. The method amounts to searching for salient paths in the combined time-frequency representation of two synthetic streams. The latter are time-series which combine the data from each detector linearly in such a way that all the GW signatures received are added constructively. We give a proof of principle for the full sky blind search in a simplified situation which shows that the joint estimation of the source sky location and chirp frequency is possible.

gr-qc↗

arXiv2006

Best chirplet chain: near-optimal detection of gravitational wave chirps

The list of putative sources of gravitational waves possibly detected by the ongoing worldwide network of large scale interferometers has been continuously growing in the last years. For some of them, the detection is made difficult by the lack of a complete information about the expected signal. We concentrate on the case where the expected GW is a quasi-periodic frequency modulated signal i.e., a chirp. In this article, we address the question of detecting an a priori unknown GW chirp. We introduce a general chirp model and claim that it includes all physically realistic GW chirps. We produce a finite grid of template waveforms which samples the resulting set of possible chirps. If we follow the classical approach (used for the detection of inspiralling binary chirps, for instance), we would build a bank of quadrature matched filters comparing the data to each of the templates of this grid. The detection would then be achieved by thresholding the output, the maximum giving the individual which best fits the data. In the present case, this exhaustive search is not tractable because of the very large number of templates in the grid. We show that the exhaustive search can be reformulated (using approximations) as a pattern search in the time-frequency plane. This motivates an approximate but feasible alternative solution which is clearly linked to the optimal one. [abridged version of the abstract]

gr-qc↗