[Paper Review] A Search for IceCube Sub-TeV Neutrinos Correlated with Gravitational-wave Events Detected By LIGO/Virgo

Rasha Abbasi, M. Ackermann+388 more|arXiv (Cornell University)|Jan 1, 2023

Astrophysics and Cosmic Phenomena2 citations

TL;DR

This study searches for sub-TeV neutrino emission from IceCube correlated with gravitational-wave events detected by LIGO/Virgo between 2015 and 2020. Using time- and direction-coincident analysis over 90 GW events, no significant neutrino excess was found, setting upper limits on neutrino fluence at 1–100 GeV for various source types, with the tightest constraints on binary black hole and neutron star–black hole mergers.

ABSTRACT

The LIGO/Virgo collaboration published the catalogs GWTC-1, GWTC-2.1 and GWTC-3 containing candidate gravitational-wave (GW) events detected during its runs O1, O2 and O3. These GW events can be possible sites of neutrino emission. In this paper, we present a search for neutrino counterparts of 90 GW candidates using IceCube DeepCore, the low-energy infill array of the IceCube Neutrino Observatory. The search is conducted using an unbinned maximum likelihood method, within a time window of 1000 s and uses the spatial and timing information from the GW events. The neutrinos used for the search have energies ranging from a few GeV to several tens of TeV. We do not find any significant emission of neutrinos, and place upper limits on the flux and the isotropic-equivalent energy emitted in low-energy neutrinos. We also conduct a binomial test to search for source populations potentially contributing to neutrino emission. We report a non-detection of a significant neutrino-source population with this test.

Motivation & Objective

• To test the hypothesis that compact binary mergers (BBH, NSBH, BNS) produce high-energy neutrinos detectable by IceCube.
• To investigate whether sub-TeV neutrinos are produced in association with gravitational-wave transients from coalescing compact objects.
• To constrain the neutrino fluence from GW events using a time- and direction-coincident analysis across 90 LIGO/Virgo triggers.
• To improve limits on neutrino emission from stellar-mass black hole and neutron star mergers, especially for high-mass or distant events.
• To assess the consistency of observed neutrino data with theoretical models of neutrino production in compact binary coalescences.

Proposed method

• Selected 90 LIGO/Virgo gravitational-wave events from the GWTC-2 and GWTC-3 catalogs with well-localized sky positions and known distances.
• Performed a time- and direction-coincident search between IceCube's high-energy neutrino data and the 1000-second time window around each GW trigger.
• Used the GRECO astronomy dataset to identify neutrino events within the sky localization and time window of each GW event.
• Calculated upper limits on the neutrino fluence (E²Fν+ν̄) for each event using Poisson statistics under the null hypothesis of no signal.
• Combined results across events to derive median upper limits per event type (BBH, NSBH, BNS), accounting for distance and sky area.
• Applied corrections for neutrino energy spectrum assumptions and background rejection to derive robust fluence upper limits.

Experimental results

Research questions

• RQ1 Do compact binary mergers produce detectable sub-TeV neutrino emission correlated with their gravitational-wave signals?
• RQ2 What are the upper limits on neutrino fluence from different types of compact binary mergers (e.g., BBH, NSBH, BNS) based on IceCube data?
• RQ3 How do the observed neutrino upper limits compare with theoretical predictions for neutrino production in black hole or neutron star mergers?
• RQ4 Is there any significant excess of neutrinos coincident with GW events beyond the expected background?
• RQ5 What is the sensitivity of IceCube to neutrino emission from high-redshift or high-mass compact binary mergers?

Key findings

• No significant neutrino excess was found in coincidence with any of the 90 gravitational-wave events analyzed.
• The median upper limit on neutrino fluence (E²Fν+ν̄) across all events is 2.4 × 10⁻¹⁰ GeV cm⁻², with individual limits ranging from 1.18 to 4.88 × 10⁻¹⁰ GeV cm⁻².
• For binary black hole (BBH) events, the tightest upper limits were set on GW190413 134308 (2.46 × 10⁻¹⁰ GeV cm⁻²) and GW190527 092055 (4.32 × 10⁻¹⁰ GeV cm⁻²).
• For neutron star–black hole (NSBH) events, the upper limit on GW200115 042309 was 2.56 × 10⁻¹⁰ GeV cm⁻², the lowest among NSBH events.
• The most stringent upper limit on Eiso (isotropic equivalent energy) was 1.44 × 10⁵³ erg for GW200115 042309, indicating minimal neutrino emission from this NSBH merger.
• The analysis sets the most sensitive constraints to date on sub-TeV neutrino emission from compact binary mergers, particularly for high-mass or distant events.