I will be applying for post-doc positions starting this fall: reach out if you are interested!

Visiting Swinburne University in Melbourne, Australia

Next on the agenda:

Talk at the "Kaba Kada" conference in Port Douglas (Australia), 23/09

🎉 Check out my latest work: https://arxiv.org/abs/2507.12170 🎉

Title

Measuring the IGM correlation length at 5<z<6.1: a fast change at the end of Reionization

Abstract

The Lyman-a forest of high redshift quasars is a powerful probe of the late stages of the Epoch of Reionization (EoR), in particular thanks to the presence of Gunn-Peterson troughs. These troughs exhibit a broad range of lengths, with some extending up to ~100a cMpc, suggesting large-scale coherent structures in the intergalactic medium (IGM). We aim to gain more insight into the presence, extent, and magnitude of correlations in the Lyman-a forest during the end of reionization, at 5<z<6.1. In particular, we want to quantify the scales over which correlations are significant in order to help inform the required size of cosmological simulations aiming to capture the evolution of the EoR. We utilize the extended XQR-30 dataset over the redshift range 5 < z < 6.1 (dz = 0.05) to explore large-scale correlations. After accounting for the relevant systematics, the flux correlation matrix proves to be a powerful tool for probing large-scale correlations across redshifts. We perform an MCMC analysis to quantify the extent and strength of the correlation, making use of several functional forms. We moreover employ new large-volume (L = 1.5 Gpc) light-cones of Lyman-a transmission implementing different reionization scenarios to interpret the observed signal, including a fiducial box employing SCRIPT. We detect strong correlations at redshifts z > 5.3, extending at least tens of Mpc and strongly increasing with redshift. Our results suggest a redshift-dependent correlation length, from L < 26.53 (68.47) Mpc at 1-sigma (2-sigma) limit at redshift z = 5.0 to L = 252.72 (+272.61,-41.61) Mpc at redshift z = 6.1. On the contrary, our simulations all demonstrate characteristic correlation scales < 60 Mpc with a very slow redshift evolution, in strong tension with our observations. The presence and redshift-dependence of correlations in the Lyman-a forest on >200 Mpc scales at z=6 indicates that cosmological simulations should be larger than this scale to adequately sample the Lyman-a forest. Despite implementing a fluctuating UVB and numerous neutral islands at z<6, and matching well the sightline scatter in the Lyman-a forest, our fiducial SCRIPT-based simulation fails to reproduce the large-scale correlations. It may be that those ingredients are necessary, but not sufficient, to understanding the unfolding of the EoR.

second-year post-doctoral researcher in astrophysics, passionate about the universe and above

Currently based in Heidelberg, I work at the Institute for Theoretical Physics in the Frontier Research Group (P.I. Dr. Sarah Bosman) on the Epoch of Reionization, the InterGalactic Medium, high-redshift quasars and much more.

I am mainly interested in the Epoch of Reionization (EoR), i.e. the process of ionization of most of the Intergalactic Medium (IGM). When did it happen? How has it progressed? Which is the role of quasars and galaxies? I like the idea of improving our knowledge of the EoR by answering these questions one paper at the time.

I am using a synergetic approach by connecting simulations/theory and experiments/observations. I started my research career using cosmological simulations of the post-EoR to disentangle dark matter models, and I am now using XQR-30 quasar spectra to constrain the HI fraction at the very end of the EoR. The EoR is a multi-scale (in time and space) process, and it needs the best comprehension of physics phenomena at all scales to be completely understood, only reachable via the synergy between theory and observations.

About me

I grew up in a small town in Northern Italy, Pieve di Soligo, in the mid of the beautiful Prosecco Hills, at the base of the Alps, but just one hour away from the gorgeous city of Venice.

I gained my Bachelor and Master in Physics at the University of Padua under the supervision of Prof. Sabino Matarrese and Dr. Michele Liguori.

I also spent a 1-year Erasmus period in Marseille, where I worked at the Laboratoire d'Astrophysique de Marseille (LAM) with Dr. Carlo Schimd.

In Nov. 2019 I moved to the Argelander Institute for Astronomy in Bonn for my Ph.D. and I have been living in Germany since then. I gained my Ph.D. in Sept. 2023, under the supervision of Prof. Dr. Cristiano Porciani.

I right away moved to the Institute for Theoretical Physics at Heidelberg University, where I have been working with Dr. Sarah Bosman as a post-doctoral researcher.