I examine galaxy peculiar velocities as a cosmological probe and compute their kernels in standard perturbation theory up to second order. With these, I construct the peculiar velocity power spectrum and bispectrum at tree level. I find agreement with the literature for the former and I derive the expression for the latter for the first time. As a byproduct, I also derive the bispectrum of the...
The peculiar velocity of the observer induces a dipolar signature on galaxy density maps derived from redshift surveys. Following Elkhashab Porciani & Bertacca paper (in prep) [see also Elkhashab, Porciani and Bertacca, Mon. Not. Roy. Astron. Soc. 509, no.2, 1626-1645 (2021), arXiv:2108.13424], in this talk, I focus on assessing the impact of this signature on the multipoles of the observed...
I will discuss how to understand and cope with projection effects concerning posterior distributions from cosmological experiments, with a particular focus on LSS surveys.
The description of gravity, i.e. the theory of general relativity, plays a crucial role in our understanding of the universe. However, confirmations of the validity of this theory on cosmological scales have hitherto eluded us. In this context, the detection of relativistic Doppler via galaxy power spectrum measurements could further confirm the validity of general relativity at scales very...
Upcoming data from galaxy surveys has the potential to yield a detection of the sum of the neutrino masses. Therefore, state-of-the-art models for full-shape analyses of correlation functions need a complete validation in the context of massive neutrino cosmologies.
We perform a joint analysis of the power spectrum and bispectrum using a suite of mock galaxy catalogs built upon N-body...
Galaxy clusters are dark-matter-dominated systems enclosed in a volume that is a high-density microcosm of the rest of the universe. I will present the most recent results on the distribution of their gravitating and baryonic mass obtained from our XMM-Newton Multi-year Heritage and Large Programmes (CHEX-MATE, X-COP) complemented with Planck maps, highlighting the role of X-ray and SZ data in...
Higher-order correlation functions (such as the three-point correlation function, 3PCF) will play a crucial role in future cosmological surveys since they complement the information provided by the (more commonly used) lower-order correlation functions (e.g., the two-point correlation function, 2PCF) allowing a significant gain in the cosmological information extracted from Large Scale...
For galaxy clustering, constraining cosmological parameters using the three-point correlation function has historically been hindered by the computational cost of modelling. Here, we introduce a new emulator developed as part of an Euclid Preparation Key Project, which significantly accelerates MCMC evaluations. For the first time in a simulation study, we present constraints on cosmological...
Galaxy surveys can be photometric (big volumes but also big redshift errors) or spectroscopic (accurate redshifts but small volumes). The technique that goes beyond this compromise is hydrogen intensity mapping (HI IM). Indeed, radio telescopes tomographically characterise the Universe, detecting the redshifted 21 cm radiation emitted by cosmic neutral hydrogen: both large areas and...
Neutral hydrogen (HI) intensity mapping is arising as a novel probe of the Large Scale Structure of the Universe, and the MeerKAT radiotelescope is being used in the so called single-dish mode to test this technique as a precursor of the SKAO. These observations are characterised by a variety of systematics and astrophysical foregrounds that are much more intense than the cosmological signal...
I will show recent updates on the Euclid strategy to control systematics of the spectroscopic sample used for galaxy clustering.
Cosmic voids, large under-dense regions in the Universe, serve as promising laboratories for extracting cosmological information. They offer opportunities to explore deviations from $\Lambda 𝐶𝐷𝑀$ and provide insights into dark energy and modification of gravity. Upcoming surveys like Euclid will enable detailed void analyses, allowing access to a huge number of voids. Voids' significance lies...
