GLOW
The project's name as a diffraction pattern: simulated light shot through an opening with the project's acronym and projected on a screen 100 mm behind them. The wavelength sweeps down until the word resolves, then drifts back and forth.

Gravitational Lensing of Waves

An ERC Consolidator Grant project · 2026–2031

Gravitational waves and fast radio bursts reach us as waves: detectors follow the oscillation of the signal, rather than the energy deposited. Gravitational lensing deflects and magnifies these signals on their way across the Universe, and when their wavelengths are commensurate with the lenses they meet (with their gravitational radius, hence with their mass), the wave diffracts instead of splitting into resolvable images. What arrives is a distorted wavefront. GLOW builds the theory, the methods and the software to read that imprint, and uses it to find lensed events, to weigh dark matter on inaccessible scales, and to test dark energy and cosmological gravity.

The science case Research programme
Funded by the European Union — European Research Council

News

Project goals

Discover lensed gravitational waves
Including sources at high redshift and near supermassive black holes
Probe dark matter, gravity and dark energy
Using diffraction, birefringence & dispersion to advance fundamental physics
Be ready for a bright future
Upcoming fast-radio-burst surveys, ground & space detectors, and multi-messenger follow-up

The science

From wave-optics lensing to data analysis, and applications to astrophysics, cosmology and fundamental physics.

Wave optics

Diffraction, interference and plasma lensing: the theory, and the algorithms to compute it.

Microlensing

Stars and remnants in the lensing galaxy, treated collectively.

Data analysis

Waveform models, population analyses, and simulation-based inference.

Distant and strong-field sources

Magnified black holes at z > 3, and sources near supermassive black holes.

Dark matter & small scales

Halos and compact objects below 106 M☉, where baryons no longer trace the mass.

Testing gravity and dark energy

Distortions on propagating waves that can't be produced in Einstein's theory.

Start here

A short introduction to the lensing of gravitational waves, for a general audience, produced by the Max Planck Institute for Gravitational Physics. Recorded scientific talks are on the Publications and talks page.

Research programme

Three work packages (WP): the theory of wave-optics lensing, the search for lensed gravitational waves, and what the results say about the contents of the Universe.

WP1

Wave-optics theory

The theory and numerical methods for wave-optics lensing: diffraction by populations of microlenses, and lensing by ionized plasma. Everything the other two work packages need in order to model realistic lenses.

WP2

Discovery and interpretation of lensed gravitational waves

Turning the theory into search results. Waveform models for microlensing signatures, population-level analyses, and accelerated inference to keep up with upcoming data.

WP3

Fundamental physics

What lensed coherent sources reveal about the constituents of the Universe: the small-scale distribution of dark matter, and the impact of dark energy on the propagation of gravitational waves.

The grant

European Research Council Consolidator Grant
Call ERC-2025-COG · grant agreement 101230608 · 60 months
Principal Investigator
Miguel Zumalacárregui

Project record on CORDIS

People, code and results

Team

11 people (postdoctoral researchers, doctoral and Master's students) and external collaborators on individual tasks.

Software & data

The GLoW wave-optics code, machine-learning inference for lensed signals, and the data behind the project's results.

Publications & talks

Papers, preprints and recorded talks, each linked to its INSPIRE record and any accompanying release.