Pedro Cataldi

Pedro Cataldi

I am a Research Associate at the Instituto de Astronomía of the Universidad Nacional Autónoma de México (IA-UNAM) in Mexico City. My research focuses on using numerical simulations to study galaxy formation, galaxy sizes, and large-scale structure. I am also a member of the LSST Dark Energy Science Collaboration (DESC).

Publications

The Physical Origins of Scatter in the Dust Attenuation Scaling Relation of Star-Forming Galaxies: Star–Dust Geometry

Published in MNRAS, 2026

Characterising the physical drivers of dust attenuation in star-forming galaxies, Lyu investigates the origin of scatter in the infrared excess (IRX) relation using approximately 32,000 local galaxies from SDSS, GALEX, and WISE. The study shows that deviations from the relation are strongly linked to UV luminosity and can be largely explained by differences in star–dust geometry, including galaxy size and inclination. UV-faint galaxies tend to be compact and edge-on, while UV-bright galaxies are more extended and face-on, highlighting the role of geometry in shaping dust attenuation.

Recommended citation: Lyu et al. (2026) https://ui.adsabs.harvard.edu/abs/2026arXiv260932284L/abstract

Halo Occupation Distribution estimation performance for LSST data

Published in A&A, 2026

Upcoming surveys such as the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) will measure galaxy clustering with unprecedented precision. In this project, I develop and test new methods to estimate the halo occupation distribution (HOD)—a key tool that links galaxies to their host dark matter haloes. Using realistic mock catalogues based on the cosmoDC2 simulation, I extend background subtraction techniques to work with photometric data and implement a galaxy group–finding algorithm. This work prepares robust tools to study galaxy clustering and galaxy–halo connections with future LSST observations.

Recommended citation: Cataldi et al. (2026) https://www.aanda.org/articles/aa/abs/2026/08/aa59674-26/aa59674-26.html

Galaxy sizes and compactness at Cosmic Dawn

Published in A&A, 2025

JWST has revealed ultra-compact, massive galaxies at z ≳ 6, challenging current models. Using FirstLight simulations, we find a universal wet compaction phase—an expansion–compaction–re-expansion cycle driven by central baryon domination—that naturally explains the observed inverted size–mass relation at Cosmic Dawn.

Recommended citation: Cataldi et al. (2026) https://www.aanda.org/articles/aa/full_html/2026/02/aa56078-25/aa56078-25.html

Gamma Analytical Modeling Evolution (GAME) I: The physical implications of deriving the stellar mass functions from z=0 to z=8

Published in MNRAS, 2025

The Gamma growth model, characterised by simple parameters, successfully reproduces the evolution of the Galaxy Stellar Mass Function over 13.5 Gyr, with minor deviations at z > 1.5. This suggests that the GSMF’s evolution follows a physically motivated, few-parameter framework consistent with JWST observations.

Recommended citation: Katsianis et al. (2025) https://academic.oup.com/mnras/article/540/1/688/8131524

Redshift evolution of the dark matter haloes shapes

Published in MNRAS, 2023

In this work, we aim at investigating the morphology evolution of Milky Way mass-like dark matter haloes selected from the CIELO and IllustrisTNG Projects. The connection between halo shapes and their environment has been studied in previous works at z=0 but their connection remains yet to be fully understood. We focus on the evolution across cosmic time of the halo shapes and the relation with the infalling material, using hydrodynamical simulations

Recommended citation: Cataldi, et al. (2023) https://doi.org/10.1093/mnras/stad1601

Fingerprints of modified gravity on galaxies in voids

Published in MNRAS, 2022

In this work, we search for detectable signatures of f(R) gravity and its chameleon screening mechanism in the baryonic and dark matter properties of simulated void galaxies. The enhancement of the gravitational acceleration can have a meaningful impact on the scaling relations as well as on the halo morphology. The galaxy rotational velocity field (calculated with the velocity of the gas disc and the acceleration fields) deviates from the typical values of the Tully-Fisher Relation (TFR) in GR

Recommended citation: Cataldi, et al. (2022) https://doi.org/10.1093/mnras/stac2122

Baryons shaping dark matter haloes

Published in MNRAS, 2020

In this work we aim at investigating the effects of baryons on the dark matter haloes structure, focusing on the correlation between the presence and importance of stellar discs and the halo shapes. We study the properties of a subsample of DM haloes from Fenix and eagle cosmological simulations.

Recommended citation: Cataldi, et al. (2020) http://dx.doi.org/10.1093/mnras/staa3988