Unless otherwise noted, the Astrophysics Seminars take place on Monday, usually every other week, at 1:30pm in Aula Caldirola.
September 2026
September 7th
Speaker 1: Luna Rampinelli (Università degli Studi di Milano)
Title 1: The chemical conditions of planet formation as revealed by spatially-resolved molecular lines observations with ALMA
Abstract 1: Protoplanetary disks are the birthplaces of planets, where planetary cores assemble, and atmospheres are accreted. The composition of these disks is expected to leave an imprint on the composition and architecture of planetary systems, while the formation of giant planets can, in turn, influence the chemical and physical structure of their natal environments. Unraveling this interplay between planets and disks, and characterizing the chemical conditions under which planetary systems form, is therefore fundamental to understanding how planets form and acquire their compositions.
In this talk, I will show how spatially resolved ALMA observations of molecular lines in protoplanetary disks can be used to probe the astrochemistry of planet formation. I will focus on three main aspects: (1) tracing the chemical link between planets and their natal disks in a system where planets are known to be forming; (2) mapping the distribution of water vapor — a key molecule for planet formation — in the regions where planets are born; and (3) tracing the chemical history of the building blocks of planets and of relevant prebiotic precursors across the different stages of star and planet formation.
Speaker 2: Viviana Pezzotta (Università degli Studi di Milano)
Title 2: A kinematic view of protoplanetary disks: structure, dynamical mass, and gravitational instability
Abstract 2: A detailed characterization of the structure and properties of protoplanetary disks is essential to understand the physical mechanisms and timescales determining planet formation. In particular, reconstructing the two-dimensional disk structure (i.e., gas temperature, pressure and velocity) is fundamental to understand the physical conditions under which planets are formed. Additionally, constraining the disk mass is crucial to assess the reservoir of material available for planet formation, and hence constrain the evolutionary pathways that connect forming planetary systems to the diversity of mature systems observed today. In this context, the kinematic information encoded in molecular line emission provides a powerful tool to tackle these open questions, offering unique constraints on many disk properties. In this talk, I leverage the potential of gas kinematics to: (1) explore how the simultaneous analysis of multiple molecular tracers probing different disk regions enables the retrieval of the disk two-dimensional structure, in particular the temperature, pressure, velocity field, and vertical stratification; (2) provide accurate measurements of disk masses based on gas dynamics, improving this promising methodology to determine the mass reservoir of planet-forming disks; (3) investigate the presence of gravitational instability in protoplanetary disks based on dynamical masses, exploring how kinematic deviations from the Keplerian motion can provide insights into its possible role in disk evolution and planet formation.
September 18th, Special seminar (aula Caldirola, 11 am)
Speaker: Carolyn Porco
Title: Meet-the-speaker format about scientific space missions in the Solar System
Abstract: Carolyn Porco is a US astrophysicist involved in fundamental Solar System missions such as Voyager and Cassini. She is an expert on Saturn’s rings and Enceladus. The format will be slightly different from the usual seminars, and it will occur in the form of a “meet-the-speaker” event: she will not give an actual seminar, but she prepared a few introductory slides to help an informal conversation.
September 21st, (!! The seminar will start at 13.15, instead of the usual time !!)
Speaker: Matilde Barberi Squarotti (Università degli Studi di Milano)
Title: Multi-tracer analysis of cosmic large-scale structure
Abstract: The Large Scale Structure (LSS) of the Universe comprises the distribution of galaxies and dark matter on cosmological scales, and it contains a wealth of information about the evolution of the Universe through cosmic time. Spectroscopic galaxy surveys and 21 cm neutral hydrogen (HI) intensity mapping are two complementary approaches to chart the distribution of matter in the Universe. Optical and near-infrared redshift surveys, such as Euclid and DESI, are mapping in detail the three-dimensional distribution of individual galaxies, while current and forthcoming radio surveys such as SKAO and its precursors, including MeerKAT, target the integrated HI emission from unresolved sources. Both reveal the underlying matter field and its growth, allowing for tests of gravity and of the physics of the early Universe.
In this seminar, I will first focus on galaxy clustering, starting with an analysis of eBOSS data to constrain primordial non-Gaussianity. I will also address the transition to the new generation of galaxy surveys, whose improved statistical precision makes the control and modelling of observational systematics essential to obtain not only precise, but also accurate, cosmological constraints. As an example, I will discuss the impact of catastrophic redshift errors (interlopers), with particular focus on the Euclid spectroscopic survey.
The pursuit of increasingly precise and accurate cosmological constraints motivates the search for complementary and independent tracers of the LSS: combining different tracers can help mitigate observational systematics while providing additional cosmological information. I will therefore introduce HI intensity mapping, discussing its potential but also the challenges that have so far prevented independent detections of the cosmological signal. I will detail the techniques developed to overcome these challenges and conclude by presenting the first detection of the HI signal from MeerKAT data, which opens new avenues for cosmology with radio surveys and multiple tracers of the LSS.
October 2026
October 5th
Speaker: Paolo D’Avanzo
Title: Gamma-ray bursts in the multi-messenger era: situation and perspectives
Abstract: Serendipitously discovered in 1967, gamma-ray bursts (GRBs) are among the most fascinating phenomena in the Universe. They are bright flashes of radiation peaking in the γ-rays, occurring at an average rate of one event per day over the whole sky at cosmological distances. Their prompt emission has duration measured in seconds and is produced in beamed outflows (jets) of relativistic matter shining in γ-rays powered by a central engine with luminosities exceeding 10^53 erg/s. Two classes of GRBs (at least), short and long, have been identified. While it has been firmly established that long GRBs originate in core-collapse supernova explosions, according to the most popular model short GRBs are produced by the merger of compact objects (neutron stars, and black holes). The prediction of a compact object binary progenitor for short GRBs has been spectacularly confirmed on Aug 17 2017, when the first gravitational wave (GW) event ever originated by a double neutron star merger was detected by LIGO-Virgo (GW 170817) and associated to the weak short GRB 170817A and to the bright kilonova (KN) AT2017gfo. In this talk I will review the situation and perspectives of our understanding of GRBs as multi-messenger sources, the recent ongoing discussion about the long/short dichotomy and the prospects for joint GW and electromagnetic studies during the next LIGO-Virgo-KAGRA observing runs.
October 19th
Speaker: TBD
Title: TBD
November 2026
November 2nd
Speaker: Alberto Sesana
Title: TBD
November 16th
Speaker: Anna Penzlin
Title: TBD
November 30th
Speaker: Giulio Scelfo (SISSA)
Title: TBD
December 2026
no dates