## HAL : Dernières publications

HAL : Dernières publications
• We present our current best estimate of the plausible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next several years, with the intention of providing information to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals for the third (O3), fourth (O4) and fifth observing (O5) runs, including the planned upgrades of the Advanced LIGO and Advanced Virgo detectors. We study the capability of the network to determine the sky location of the source for gravitational-wave signals from the inspiral of binary systems of compact objects, that is binary neutron star, neutron star–black hole, and binary black hole systems. The ability to localize the sources is given as a sky-area probability, luminosity distance, and comoving volume. The median sky localization area (90% credible region) is expected to be a few hundreds of square degrees for all types of binary systems during O3 with the Advanced LIGO and Virgo (HLV) network. The median sky localization area will improve to a few tens of square degrees during O4 with the Advanced LIGO, Virgo, and KAGRA (HLVK) network. During O3, the median localization volume (90% credible region) is expected to be on the order of $10^{5}, 10^{6}, 10^{7}\mathrm {\ Mpc}^3$ for binary neutron star, neutron star–black hole, and binary black hole systems, respectively. The localization volume in O4 is expected to be about a factor two smaller than in O3. We predict a detection count of $1^{+12}_{-1}$($10^{+52}_{-10}$) for binary neutron star mergers, of $0^{+19}_{-0}$($1^{+91}_{-1}$) for neutron star–black hole mergers, and $17^{+22}_{-11}$($79^{+89}_{-44}$) for binary black hole mergers in a one-calendar-year observing run of the HLV network during O3 (HLVK network during O4). We evaluate sensitivity and localization expectations for unmodeled signal searches, including the search for intermediate mass black hole binary mergers.
• On May 21, 2019 at 03:02:29 UTC Advanced LIGO and Advanced Virgo observed a short duration gravitational-wave signal, GW190521, with a three-detector network signal-to-noise ratio of 14.7, and an estimated false-alarm rate of 1 in 4900 yr using a search sensitive to generic transients. If GW190521 is from a quasicircular binary inspiral, then the detected signal is consistent with the merger of two black holes with masses of 85-14+21 M⊙ and 66-18+17 M⊙ (90% credible intervals). We infer that the primary black hole mass lies within the gap produced by (pulsational) pair-instability supernova processes, with only a 0.32% probability of being below 65 M⊙. We calculate the mass of the remnant to be 142-16+28 M⊙, which can be considered an intermediate mass black hole (IMBH). The luminosity distance of the source is 5.3-2.6+2.4 Gpc, corresponding to a redshift of 0.82-0.34+0.28. The inferred rate of mergers similar to GW190521 is 0.13-0.11+0.30 Gpc-3 yr-1.
• We present results from offline searches of Fermi Gamma-ray Burst Monitor (GBM) data for gamma-ray transients coincident with the compact binary coalescences observed by the gravitational-wave (GW) detectors Advanced LIGO and Advanced Virgo during their first and second observing runs. In particular, we perform follow-up for both confirmed events and low significance candidates reported in the LIGO/Virgo catalog GWTC-1. We search for temporal coincidences between these GW signals and GBM triggered gamma-ray bursts (GRBs). We also use the GBM Untargeted and Targeted subthreshold searches to find coincident gamma-rays below the on-board triggering threshold. This work implements a refined statistical approach by incorporating GW astrophysical source probabilities and GBM visibilities of LIGO/Virgo sky localizations to search for cumulative signatures of coincident subthreshold gamma-rays. All search methods recover the short gamma-ray burst GRB 170817A occurring ~1.7 s after the binary neutron star merger GW170817. We also present results from a new search seeking GBM counterparts to LIGO single-interferometer triggers. This search finds a candidate joint event, but given the nature of the GBM signal and localization, as well as the high joint false alarm rate of $1.1 \times 10^{-6}$ Hz, we do not consider it an astrophysical association. We find no additional coincidences.

En construction.

Jeudi 25 Mars à 11h : "Projections climatiques locales durant le XXIe siècle, de Nice au Mercantour",

séminaire grand public, par Nicolas Martin, géographe et climatologue, enseignant à l'UCA.

Le Laboratoire ARTEMIS recrute un Ingénieur de recherche Photonique/Lasers, CDI de 1 an

[english version below]

Le Laboratoire ARTEMIS recrute un Ingénieur de recherche Photonique/Lasers, CDI de 1 an

L’unité de recherche Artemis réunit des spécialistes des lasers et du traitement du signal, des mathématiciens, des astrophysiciens des objets compacts pour créer une antenne d’un type nouveau, détectant des signaux encore jamais détectés : Virgo. Depuis 1999, sa conception, la modélisation de sources cosmiques et de leurs signaux sont au coeur de l’activité d’Artemis.

Virgo est un détecteur de l’extrême dont les performances reposent en premier lieu sur les propriétés exceptionnelles des lasers et des miroirs. C’est au CSNSM et au LAL, à Orsay que ces méthodes utilisées aujourd’hui ont été développés sous la direction d’Alain Brillet, avant que l’équipe ne rejoigne l’Observatoire de la Côte d’Azur.Le design optique de Virgo a été guidé par la modélisation initiée et développée par Jean-Yves VINET et Jean-Daniel FOURNIER. Celle-ci est toujours utilisée pour les développements actuels.

Aller au haut