Antonio Ragagnin

Position: Researcher

Contact info

• Room: B-3E13
• Phone: +39 051 6357 394
• Email: antonio.ragagnin@inaf.it

Personal info

• Orcid: 0000-0002-8106-2742
• Web: https://aragagnin.github.io/

Activities

I am a fixed-term research staff member at INAF-OAS. I specialize in cosmological hydrodynamic simulations, zoom-in simulations of galaxy clusters, high-performance computing (HPC), GPUs, self-interacting dark matter, and multi-wavelength mock observations (X-ray, SZ, optical, as well as derived weak and strong lensing signals). Collaborations: Euclid, Magneticum, OpenGadget3, HydroSims, Darkium

Curriculum vitae

Some of my recent scientific contributions:

Projection effects and multi-wavelength studies: I am the lead author of a paper for the Euclid Collaboration: Ragagnin et al. (2025). Within this collaborative effort between observational and simulation teams, I produced mock observations from various multi-wavelength data sources (X-ray, SZ, optical, and inferred weak lensing signals). The paper presents a Euclid-tailored covariance matrix for realistic mock observations across these wavelengths and explores the impact of projection effects, which will assist future cosmology studies based on multi-wavelength observations.

Galaxy clusters with self-interacting dark matter: The promising particle-physics-motivated self-interacting dark matter model can strongly influence the evolution of halos. In Ragagnin et al. (2024), I present one of the first simulation suites (based on Dianoga ICs; see Rasia et al. 2014) of galaxy clusters incorporating full baryon physics and SIDM. We found that SIDM can significantly affect the abundance of satellites.

On the GG strong-lensing tension with ΛCDM: In Ragagnin et al. (2022a), we tested the well-motivated hypothesis that AGN physics could resolve this issue and we concluded that it can not. No current ΛCDM simulation reproduces the observed cores of galaxy clusters. While investigating this problem, I found that this tension is closely linked to the fact that most hydrodynamic simulations tend to overestimate BCG masses.

Impact of cosmological parameters in galaxy clusters: The package hydro_mc implements the Ragagnin et al. (2021) conversion of mass, concentration, and sparsity parameters between virial and overdensities of Δ = 2500, 500, and 200 (both mean and critical). See the hydro_mc web app or the repo github.com/aragagnin/hydro_mc.

Characterising X-ray faint galaxy clusters: It is well known that X-ray observations may be biased toward peaked and centrally concentrated gas distributions, potentially missing a population of X-ray faint objects. In Ragagnin et al. (2022b), I found that clusters that are X-ray faint are gas-poor because they are old and relaxed, thus allowing sufficient time for the gas to be depleted.

Work experiences:

Latest papers on ADS
(based on ORCID, see here how to claim missing papers)

1. Euclid: I. Overview of the Euclid mission, Astronomy and Astrophysics, 2025
2. Euclid preparation: LXVI. Impact of line-of-sight projections on the covariance between galaxy cluster multi-wavelength observable properties: insights from hydrodynamic simulations, Astronomy and Astrophysics, 2025
3. Euclid preparation: LXIII. Simulations and non-linearities beyond Lambda cold dark matter. 2. Results from non-standard simulations, Astronomy and Astrophysics, 2025
4. Weak lensing mass bias and the alignment of centre proxies, Monthly Notices of the Royal Astronomical Society, 2024
5. Dianoga SIDM: Galaxy cluster self-interacting dark matter simulations, Astronomy and Astrophysics, 2024
6. Euclid preparation. XXXIX. The effect of baryons on the halo mass function, Astronomy and Astrophysics, 2024
7. Exploring the low-mass regime of galaxy-scale strong lensing: Insights into the mass structure of cluster galaxies, Astronomy and Astrophysics, 2023
8. The probability of galaxy-galaxy strong lensing events in hydrodynamical simulations of galaxy clusters, Astronomy and Astrophysics, 2022
9. Simulation view of galaxy clusters with low X-ray surface brightness, Astronomy and Astrophysics, 2022
10. Galaxies in the central regions of simulated galaxy clusters, Astronomy and Astrophysics, 2022