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M. Bitossi

Publications and source records attributed to M. Bitossi.

5 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2020

Optically targeted search for gravitational waves emitted by core-collapse supernovae during the first and second observing runs of advanced LIGO and advanced Virgo

We present the results from a search for gravitational-wave transients associated with core-collapse supernovae observed within a source distance of approximately 20 Mpc during the first and second observing runs of Advanced LIGO and Advanced Virgo. No significant gravitational-wave candidate was detected. We report the detection efficiencies as a function of the distance for waveforms derived from multidimensional numerical simulations and phenomenological extreme emission models. The sources with neutrino-driven explosions are detectable at the distances approaching 5 kpc, and for magnetorotationally driven explosions the distances are up to 54 kpc. However, waveforms for extreme emission models are detectable up to 28 Mpc. For the first time, the gravitational-wave data enabled us to exclude part of the parameter spaces of two extreme emission models with confidence up to 83%, limited by coincident data coverage. Besides, using ad hoc harmonic signals windowed with Gaussian envelopes, we constrained the gravitational-wave energy emitted during core collapse at the levels of 4.27 × 10^(−4) Mꙩc^(2) and 1.28 × 10^(−1) Mꙩc^(2) for emissions at 235 and 1304 Hz, respectively. These constraints are 2 orders of magnitude more stringent than previously derived in the corresponding analysis using initial LIGO, initial Virgo, and GEO 600 data.

B. P. Abbott↗
NASA NTRS2019

Directional limits on persistent gravitational waves using data from Advanced LIGO’s first two observing runs

We perform an unmodeled search for persistent, directional gravitational wave (GW) sources using data from the first and second observing runs of Advanced LIGO. We do not find evidence for any GW signals. We place limits on the broadband GW flux emitted at 25 Hz from point sources with a power law spectrum at F(α;Θ) < (0.05–25) × 10^(−8) erg/sq. cmsHz and the (normalized) energy density spectrum in GWs at 25 Hz from extended sources at Ω(α)(Θ) < (0.19–2.89) × 10^(−8) per sr where α is the spectral index of the energy density spectrum. These represent improvements of 2.5–3× over previous limits. We also consider point sources emitting GWs at a single frequency, targeting the directions of Sco X-1, SN 1987A, and the Galactic center. The best upper limits on the strain amplitude of a potential source in these three directions range from h(0) < (3.6–4.7) × 10^(−25), 1.5× better than previous limits set with the same analysis method. We also report on a marginally significant outlier at 36.06 Hz. This outlier is not consistent with a persistent gravitational-wave source as its significance diminishes when combining all of the available data.

B. P. Abbott↗
NASA NTRS2019

GWTC-1: A Gravitational-Wave Transient Catalog of Compact Binary Mergers Observedby LIGO and Virgo During the First and Second Observing Runs

We present the results from three gravitational-wave searches for coalescing compact binaries with component masses above1M during the first and second observing runs of the advanced gravitational-wave detector network. During the first observing run (O1), from September 12, 2015 to January 19, 2016, gravitational waves from three binary black hole mergers were detected. The second observing run (O2), which ran from November 30, 2016 to August 25, 2017, saw the first detection of gravitational waves from a binary neutron star in spiral, in addition to the observation of gravitational waves from a total of seven binary black hole mergers, four of which we report here for the first time: GW170729, GW170809, GW170818, and GW170823. For all significant gravitational-wave events, we provide estimates of the source properties. The detected binary black holes have total masses between18.6þ3.2−0.7M and 84.4þ15.8−11.1M and range in distance between 320þ120−110 and 2840þ1400−1360Mpc. No neutron star–black hole mergers were detected. In addition to highly significant gravitational-wave events, we also provide a list of marginal event candidates with an estimated false-alarm rate less than 1 per 30 days. From these results over the first two observing runs, which include approximately one gravitational-wave detection per 15 days of data searched, we infer merger rates at the 90% confidence intervals of 110−3840Gpc−3y−1 for binary neutron stars and 9.7−101Gpc−3y−1 for binary black holes assuming fixed population distributions and determine a neutron star–black hole merger rate 90% upper limit of 610Gpc−3y−1.

Astrophysics↗
NASA NTRS2019

Low-Latency Gravitational-Wave Alerts for Multimessenger Astronomy During the Second Advanced LIGO and Virgo Observing Run

Advanced LIGO’s second observing run (O2), conducted from 2016 November 30 to 2017 August 25, combined with Advanced Virgo’s first observations in 2017 August, witnessed the birth of gravitational-wave multimessenger astronomy. The first ever gravitational-wave detection from the coalescence of two neutron stars, GW170817, and its gamma-ray counterpart, GRB 170817A, led to an electromagnetic follow-up of the event at an unprecedented scale. Several teams from across the world searched for EM/neutrino counterparts to GW170817, paving the way for the discovery of optical, X-ray, and radio counterparts. In this article, we describe the online identification of gravitational-wave transients and the distribution of gravitational-wave alerts by the LIGO and Virgo collaborations during O2. We also describe the gravitational-wave observables that were sent in the alerts to enable searches for their counterparts. Finally, we give an overview of the online candidate alerts shared with observing partners during O2. Alerts were issued for 14 candidates, 6 of which have been confirmed as gravitational-wave events associated with the merger of black holes or neutron stars. Of the 14 alerts, 8 were issued less than an hour after data acquisition.

Gravtational waves↗