EPTA meeting, Paris - Jun 2026

Session

Contributed talks

3 juin 2026, 16:00

APC

22. Updates for the Interpretation WG

Nataliya Porayko (MPIfR)

03/06/2026 16:00

I would like to give an overview of activities undertaken in the Interpretation WG.

1. Inflationary interpretation of the gravitational-wave signal in the European Pulsar Timing Array DR2 data with constraints

Delphine Perrodin

03/06/2026 16:20

The second data release of the European Pulsar Timing Array (EPTA) collaboration provides
evidence for the presence of a gravitational-wave (GW) background. In this work, we explore a
potential cosmological interpretation of this signal in terms of inflationary scenarios. We parametrize
the tensor power spectrum in terms of the tensor-to-scalar ratio r, the tensor spectral index nt,...

5. Characterisation of Continuous Gravitational Waves with Deep Learning: Detection and Sky Localisation

Ludovica Carbone (University of Milano-Bicocca)

03/06/2026 16:40

Accurate localisation of continuous gravitational waves (CGWs) from supermassive black hole binaries (SMBHBs) remains one of the key challenges in Pulsar Timing Array (PTA) data analysis. Traditional searches based on the $\mathcal{F}_e$ statistic provide a robust analytic framework, but the resulting sky maps are strongly affected by the PTA antenna pattern, which redistributes signal power...

13. Towards multi-messenger observations of supermassive black hole binaries

Maria Charisi (IA-FORTH & Washington State University)

03/06/2026 17:00

Supermassive black hole binaries (SMBHBs) are exceptional multi-messenger targets, since on top of their low-frequency gravitational waves (GW), they may emit bright electromagnetic (EM) emission. I will describe a recently developed joint likelihood method that combines EM and pulsar timing array (PTA) data, which was shown to improve the binary parameter estimation. I will also discuss the...

17. Impact of Dispersion Measure Noise Modeling on Gravitational-Wave Background

Danilo Zecca (Università del Salento)

03/06/2026 17:20

We investigated the impact of dispersion measure (DM) variations on the recovery of a stochastic Gravitational Wave Background (GWB) in Pulsar Timing Array (PTA) datasets, extending the chromatic noise analysis of Iraci et al. (2024). We generated multiple synthetic PTA datasets for different configurations of a 25-pulsar array, combining LOFAR-like low-frequency observations with Nançay...

4. Looking for non-gaussianity in PTA through the four-point correlator

Massimo Vaglio (SISSA)

04/06/2026 09:00

Pulsar Timing Arrays have recently reported strong evidence for a stochastic gravitational wave background. In standard analyses, this is modeled through pulsar-dependent Fourier coefficients assumed to follow Gaussian statistics, so that the signal is fully characterized by its two-point function. However, if the background arises from a finite population of inspiralling supermassive black...

11. Modeling the nHz gravitational wave background with t-process

Beatrice Eleonora Moreschi (University of Milano-Bicocca)

04/06/2026 09:20

Unveiling the nature of the nanoHz gravitational wave signal reported by Pulsar Timing Array collaborations is the next goal of low-frequency GW astronomy. The signal likely originates from the incoherent superposition of GWs emitted by a population of supermassive black hole binaries (SMBHBs). The discrete nature of the population, environmental effects and eccentricity are expected to...

15. Possible imprints of a clustered Universe in astrophysical PTA GW data

Martin Pijnenburg

04/06/2026 09:40

The compelling evidence for the presence of nHz gravitational waves (GWs) in pulsar timing data calls for a refinement of what can and cannot be expected beyond vanilla scenarios. Under the hypothesis of an astrophysical origin for the GWs, we discuss possible imprints left in the signal by the fact the Universe is inherently clustered, with anisotropic large scale structure.
At the...

16. Downsampling PTA data

Mikel Falxa

04/06/2026 10:00

Pulsar Timing Array (PTA) data are challenging to analyze due to their uneven sampling and the presence of observational gaps. In gravitational wave (GW) searches with PTA data, the signal is expected to dominate primarily at low frequencies, motivating the question of whether the data can be efficiently downsampled without significant loss of information. We propose a method to generate...

24. Methods for GW searches and pulsar noise characterisation from gamma-ray photons

Serena Valtolina

04/06/2026 11:00

Accurately modelling pulsar noise is one of the main challenges for current radio PTA experiments. For many pulsars, the data are not informative enough to efficiently solve the covariance between chromatic and achromatic processes. In gamma-ray PTA (GPTA) experiments instead, the sensitivity to stochastic processes is limited by the low photon flux of gamma-ray pulsar observations; thus, the...

6. Observation Strategy Study of Pulsar Timing Array

Yang Liu (Shanghai Astronomical Observatory, Chinese Academy of Sciences)

04/06/2026 11:20

This project aims to investigate optimal observational modes of radio interferometric arrays for diverse scientific goals (e.g., PTAs) using numerical simulation tools.
We develop an open-source software framework capable of generating simulated pulsar timing data and injecting multiple signals, including gravitational waves. Leveraging existing observational datasets, we use this framework...

20. Resolving signals with finite angular size in the GWB sky

Egor Ledenev (MSU SAI), Viacheslav Chernosov (MIPT)

04/06/2026 11:40

In this work, we consider the case of a model GWB source with a Gaussian power spectrum on a sphere, and obtain an analytical expression of the overlap reduction function of the signals of two pulsars, which generalizes the previously obtained expressions for isotropic and delta-shaped model sources. Using the generalized correlation function allows us to determine the characteristic angular...

21. The First search for gravitational waves with the DR2low dataset

Irene Ferranti (University of Milano-Bicocca)

04/06/2026 12:00

The EPTA+InPTA DR2new+ dataset has recently been combined with low-frequency measurements from LOFAR and NenuFAR (Iraci et al., 2025), with the aim of generating a dataset capable of disentangling the DM variation noise from achromatic red noise and the stochastic background. Simulations have shown that better distinguishing between these components is expected to improve sensitivity to the...