Conveners
Cosmology
- Chair: Andrei Mesinger
Cosmology
- Chair: Andrei Mesinger
Neutral hydrogen (HI) intensity mapping is emerging as a revolutionary probe of the Large Scale Structure of the Universe and the MeerKLASS collaboration (MeerKAT Large Area Synoptic Survey) is currently running precursor analyses aiming to test the single-dish technique for mapping the cosmological 21cm signal using MeerKAT data. This signal, originating from the line emission at 1420MHz of...
The Evolutionary Map of the Universe (EMU) is a radio continuum survey that, using the Australian SKA Pathfinder (ASKAP), aims to map the entire Southern Sky by 2028 and is expected to detect approximately 20 million extragalactic radio objects. Measuring the distribution of radio continuum galaxies on the sky provides a fast and accessible probe of the distribution of matter in the Universe,...
Observations of the neutral hydrogen (HI) 21-cm signal have the potential to map out the large-scale structures (LSS) of our Universe during the post-reionization era (z ≲ 6). Several present and future experiments are planned to give their efforts to probe the signatures of the LSS inherent in the expected signal over a large redshift range. A correct prediction of the expected signal demands...
Dark matter and dark energy represent 95% of the Universe and they are still unknown. Gravitational lensing is one of the most powerful tools for constraining the "dark Universe", as it can directly infer dark energy (via gravitational time delays) and dark matter (via low-mass lenses). In this talk we will overview these fundamental investigations and show our latest results from the...
The SKAO's ability to survey the radio continuum and neutral hydrogen (HI) signals with a wide sky coverage and up to high redshift makes it a cardinal experiment to probe the large-scale structure of the Universe. Radio continuum galaxies and the HI signal from intensity mapping (IM) constitute cosmological tracers capable of enhancing the astrophysical and cosmological information embedded...
The peculiar motion of the observer induces boosting effects in the anisotropy pattern of the background. The monopole frequency spectrum of the background is altered and transferred to higher multipoles, most prominently to the dipole, which retains the imprint of the isotropic background spectrum. Thanks to the high sensitivity and resolution of SKA, these patterns can be extracted even from...
Our peculiar velocity imprints a dipolar signal on the large-scale clustering of galaxies. This effect leaves a distinctive oscillatory pattern on the power spectrum multipoles of galaxy clustering, which we refer to as FOTO effect (Finger Of The Observer). By performing a boosting technique on a galaxy catalog, we are able to use exploit this signature to constrain the magnitude and direction...
Generating a large set of HI intensity mapping simulations encompassing large cosmological volumes implies a prohibitive computational burden if one relies on traditional N-body-based methods. As such, a number of alternatives to overcome this issue have emerged over the years, from simple analytical prescriptions to more complex semi-empirical methods. In this talk, I will present an effort...
Radio telescopes tomographically characterise the Universe thanks to detecting the redshifted 21 cm radiation emitted by cosmic neutral hydrogen, HI. One of the most significant challenges for performing this measurement is removing the contaminants, i.e., orders of magnitude more intense foregrounds coupled with not-yet-characterised instrumental systematics. In this talk, I will discuss how...
The cosmological 21-cm signal is sourced from hyperfine transitions in neutral hydrogen atoms. Yet, although the abundance of hydrogen atoms follows the baryon density field, semi-numerical codes that simulate the 21-cm signal simplify their treatment as if all the matter in the Universe was in the form of collisionless cold dark matter (CDM). In this talk, I will discuss how separating the...
THe $M_{\rm HI}-M_{\rm halo}$ relation is a fundamental tool in cosmology, to perform cosmological inference from HI surveys. This relation has been so far constrain observationally in a robust way only in the nearby Universe, and has been studied in theory from state-of-the-art cosmological hydrodynamic simulations. Nonetheless, no dependence on secondary properties (also called 'assembly...
