〰️ DRAFT RESEARCH PROPOSAL · GRAVITATIONAL WAVES + COSMIC RAYS · LIGO/KAGRA + PIERRE AUGER

LIGO/Virgo/KAGRA Continuous GW Search + Pierre Auger UHECR Anisotropy Correlation — Omega Centauri Multi-Messenger Program

Two synergistic initiatives leveraging existing public datasets: narrowband continuous gravitational wave searches for known OC pulsars, and ultra-high-energy cosmic ray anisotropy cross-correlation with neutrino and GW triggers · Working draft · April 2026

Initiative I: LIGO/Virgo/KAGRA Narrowband Continuous Gravitational Wave Search

I.1 Scientific Rationale

Continuous gravitational waves (CWs) — persistent, nearly monochromatic GW signals — are emitted by rapidly rotating non-axisymmetric compact objects: neutron stars, pulsars, and exotic compact binaries. OC's high stellar density makes it a natural factory for such systems. A targeted search concentrates sensitivity on specific, known objects rather than performing a computationally expensive blind all-sky scan.

From the OCS perspective, there is an additional motivation: the Blandford-Znajek mechanism operating at the IMBH would involve a rapidly spinning black hole with a structured accretion disk — a potential source of persistent quadrupolar GW emission if the disk is sufficiently asymmetric. While highly speculative, such a signal would be unique to an active IMBH rather than a dark cluster, providing yet another discriminant.

I.2 Methodology

Target catalog: Compile positions, spin frequencies, and spin-down rates for all known radio pulsars and gamma-ray sources associated with OC using:

• ATNF Pulsar Catalogue (Manchester et al. 2005)
• MeerKAT/Parkes ephemerides from Chen et al. (2024) and Freire et al.
• Fermi-LAT 4FGL-DR4 sources within 0.3° of OC

Analysis pipeline: Apply F-statistic matched-filtering to public LIGO/Virgo/KAGRA O4 data (available via GWOSC). The F-statistic correlates detector strain with a theoretical CW template, searching for excess power in a narrow frequency band around 2 × f_spin of each target pulsar, with a small range of frequency derivatives accounting for spin-down.

Public data access: All O4 data available via gwosc.org. O5 (enhanced sensitivity, beginning ~2027) will further improve reach. Analysis frameworks: LALSuite (lalsuite), PyFstat (Ashton & Prix 2018).

Expected upper limits: For a targeted search at O4 sensitivity, GW strain upper limits of h₀ < 10⁻²⁶–10⁻²⁷ are achievable for the most sensitive frequency bands, constraining the ellipticity of any neutron star in OC to ε < 10⁻⁷–10⁻⁸.

I.3 Novelty

Narrowband CW searches for known pulsars are standard during O4 (see Narrowband searches for CWs from known pulsars in the first two parts of O4, arXiv:2603.25938). This proposal's novelty is the targeted application to OC as a technosignature site of interest — treating a standard astrophysics technique as a multi-messenger component of a coherent observational strategy, rather than an isolated search.

Initiative II: Pierre Auger Ultra-High-Energy Cosmic Ray Anisotropy Correlation

II.1 Scientific Rationale

Ultra-high-energy cosmic rays (UHECRs; E > 55 EeV) are the most energetic particles known. Their arrival direction distribution shows statistically significant large-scale anisotropies (Pierre Auger Collaboration, Science 2017; arXiv:1709.07321). OC's direction has been suggested as a possible hotspot region in some analyses. While UHECRs are charged and deflected by intergalactic magnetic fields (typically 1°–10° for protons at 60 EeV over ~5 Mpc), their collective arrival direction anisotropy can still indicate source locations when correlated with neutral messengers.

The key scientific question: Is there a statistically significant excess of UHECR events from the OC direction that is spatially correlated with high-energy neutrino events (IceCube/KM3NeT) and/or GW triggers (LIGO/KAGRA)? A single UHECR hotspot toward OC is consistent with conventional astrophysics (OC's dense stellar core may host exotic compact binaries). However, a correlated excess across three different messenger types — cosmic rays, neutrinos, and gravitational waves — would be extremely difficult to explain with standard models.

II.2 Methodology

Dataset 1: Pierre Auger UHECR events

• Select events with E > 55 EeV from Auger public data release (Pierre Auger Collaboration 2022, JCAP)
• OC declination (δ = −47°) is within Auger's optimal southern-sky coverage (latitude −35°, full coverage to δ < −55°)
• Define angular search radius: 3° (conservative, accounting for magnetic deflection) and 1° (optimistic)

Dataset 2: IceCube/KM3NeT high-energy neutrino alerts

• IceCube public event list: Track events with E > 100 TeV from 10-year dataset
• KM3NeT ARCA alert events as they become available

Dataset 3: LIGO/Virgo/KAGRA GW transient events

• GWTC-3 and ongoing O4 events from GWOSC
• Use sky localization posterior as spatial weight

Statistical analysis:

The "convergence of evidence" test: The analysis requires not just a UHECR excess but a temporally and spatially correlated excess across multiple messengers. Random coincidences across three physically independent detectors with different systematics are exponentially unlikely.

II.3 Background Considerations

The Galactic Center region (Sgr A*, δ ≈ −29°) is the dominant astrophysical UHECR candidate in the southern sky. OC at δ = −47° is distinct and separated by ~18° — well-resolvable with Auger's angular resolution. The isotropic cosmic-ray background requires careful modelling; the null hypothesis is an isotropic flux modulated only by the Auger exposure function.

Comparative Feasibility

Work Plan

Budget

References