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Investigating the link between protoplanets, disk substructures and disk winds

Sede A. Riccò Via Santa Sofia 78, Catania

Protoplanetary disks are now routinely observed around young stars but the planets they produce remain elusive to detect. So far, we have only one confirmed direct detection of protoplanets in the disk of PDS 70, with some tentative results (e.g. AB Aur). Yet disk structures are found almost ubiquitously across the sample of resolved disks. We are investigating the potential relationship between inner disk winds and outflows (traced by optical emission lines, such as ), and the presence and type of disk substructures. We aim to determine whether or not the various substructures are the direct results of protoplanet formation.
I will present new results from recent and archival observations of PDS 70. In order to investigate such connections between winds, substructures and planets, we turn to the one system where we have certainly detected the planets. We have carefully applied established techniques to the high-resolution spectra to reveal previously unseen forbidden emission profiles. These results suggest a significant wind originating from the inner disk. We compare these results and measurements of the mass accretion rate and disk properties to those of other weakly accreting young stars and those with transition disks.
We are also carrying out this investigation for the PENELLOPE/ULLYSES sample of ~80 young stars. This complements existing surveys of such winds/outflows, whilst allowing for further exploration of the relation to disk substructures, towards a more complete statistical survey.

Elucidating diffuse Galactic synchrotron emission for precision 21cm and CMB cosmology

Sede A. Riccò Via Santa Sofia 78, Catania

The next generation of Cosmic Microwave Background experiments are poised to probe the inflationary period of the Universe through the measurement of primordial B-modes, whilst 21cm experiments are observing the reionization history of the early Universe and formation of Large-Scale Structure through the mapping of neutral hydrogen. These two complementary fields span the radio to microwave frequency regimes and share a pivotal data reduction task: foreground component separation.

Diffuse Galactic synchrotron emission is the dominant foreground for arcmin/degree scale cosmological surveys operating across MHz frequencies in intensity, and at all frequencies under 60 GHz in polarised intensity. In this talk I will present measurements of the synchrotron spectral index and curvature between 73 MHz and 1 GHz through the combined use of pilot MeerKLASS, Haslam, Maipu/MU and LWA data. I will discuss the advances that can be made to component separation algorithms thanks to more sophisticated foreground emission modelling and will present a spatially complex, all-sky model of the synchrotron spectral index formed using convolutional neural networks trained on sets of both high- and low-resolution empirical data. Such advances will, and already are, expanding our understanding of the spatial and spectral form of this complex emission; ameliorating component separation for both CMB and 21cm intensity mapping experiments.

Our Universe in Simulation

Sede A. Riccò Via Santa Sofia 78, Catania

Ongoing and upcoming cosmological surveys—including the Simons Observatory, LiteBIRD, Rubin LSST, Euclid, DESI, PSF, SPHEREx, and the Roman Space Telescope—will deliver observations of unprecedented precision. Joint analyses across these surveys will be essential for uncovering fundamental physics, including the nature of inflation, dark energy, dark matter, neutrino mass, and more. In this talk, I will discuss the opportunities, challenges, and strategies for simulating our universe across multiple wavelengths to realize these goals.In this talk, I will discuss the motivations and objectives of the project, the published results, ongoing studies and the future developments.

The Nature of Polarized Sources in the MIGHTEE XMM-LSS Deep Field

Sede A. Riccò Via Santa Sofia 78, Catania

This study explores the polarized emission of the faint extragalactic radio sources in the MIGHTEE (MeerKAT International Giga-Hertz Tiered Extragalactic Exploration, Jarvis et al., 2016) survey in order to systematically study cosmic magnetic fields in galaxies to high redshift. Reaching a sensitivity of 1.5 µJy/beam at a resolution of 5 arcseconds, MIGHTEE is providing an opportunity to chart the evolution of polarized emission from distant galaxies over cosmic time.
The MIGHTEE survey detects polarized emission for a large number of radio sources down to total intensity flux densities of the order of 100 µJy. At these flux densities the source population is increasingly dominated by star-forming galaxies (SFGs) as opposed to active galactic nuclei (AGNs). While polarized emission of AGN can be traced to very distant galaxies, polarized emission of SFGs at moderate distance has been detected only once.
I use multi-wavelength criteria to classify MIGHTEE radio objects as either SFG or AGN. I perform Rotation Measure Synthesis (RMSY) on the spectro-polarimetric data cubes and use the polarization and RMSY spectra to search for polarized emission. A comparative analysis of the polarization properties of SFGs and AGNs is performed. The analysis is extended to the lowest possible flux densities using stacking techniques. I will show preliminary results of the MeerKAT polarization studies of radio sources down to a sensitivity at the micro-Jansky level.