Calendar

Abstract: Saranno esaminati i principali contributi scientifici dati dall’Osservatorio di Palermo allo sviluppo dell’astronomia nel corso della sua pluricentenaria attività scientifica, soffermandosi sui periodi più significativi e sui fattori che hanno determinato gli importanti risultati scientifici ottenuti, dalla fine del Settecento agli ultimi decenni del secolo scorso, dagli astronomi in forze all’Osservatorio.

Categorie: Aula: Seminario

Ott

ven

Lezione Corso: “Magnetohydrodynamics in Astrophysical Processes”

Biglietti

Ott 31@9:00–12:00

Categorie: Aula: Lezioni

Nov

gio

Lezione Corso: “Magnetohydrodynamics in Astrophysical Processes”

Biglietti

Nov 6@9:00–12:00

Categorie: Aula: Lezioni

Seminario: Maria Messineo (UniBo)

Biglietti

Nov 6@15:00–17:00

Titolo: Bright late-type stars in the thin Disk of the Milky Way

Abstract: Red supergiants (RSGs) and asymptotic giant branch (AGB) stars are the
brightest sources at infrared wavelengths, detectable at a distance
of a few megaparsecs —- even in heavily obscured galactic centers.
Through winds and mass loss, they enrich and sculpt the interstellar
medium.
Despite similar spectral energy distributions and apparent magnitudes,
RSGs and AGBs trace distinct spatial structures of a galaxy.
AGBs trace well the gravitational potential, including the central bar,
and span ages from 50 Myr to a Hubble time. RSGs, aged 4.5–40 Myr, decorate
the spiral arms, the central molecular disk, and the bar’s endpoints.
The Milky Way offers the nearest laboratory for resolved stellar
populations
in a barred galaxy, however, dust obscuration and distance uncertainties
hinder
clean separation of RSGs and AGBs -— a critical step for mapping Disk
structure
and star-formation history.
Over the past several years, I have developed methods to estimate
extinction
by partitioning interstellar and circumstellar components, to obtain better
luminosity and to distinguish RSGs from AGBs. I will highlight key
challenges
and solutions, including extinction-free colors as interstellar
extinction proxies,
GLIMPSE color–color diagrams, and Gaia–2MASS criteria.
Finally, I will present a new Gaia catalog of ~700 bona fide optical RSGs,
detailing its construction, temperature, and luminosity characterization.

Categorie: Aula: Seminario

Nov

mar

Seminario: Elina Lindfors (University of Turku)

Biglietti

Nov 11@10:00–12:00

Titolo: Association of the astrophysical neutrinos with flares from relativistic jets launched by supermassive black holes?

Abstract:

Over the past decade, the IceCube Neutrino Observatory has detected a few hundreds of high-energy (HE) neutrinos from cosmic sources. Despite numerous studies searching for their origin, it is still not known which source populations emit them. A few confident individual associations exist with active galactic nuclei (AGN), mostly with blazars which are jetted AGN whose jet points in our direction. Nonetheless, on a population level, blazar-neutrino correlation strengths are rather weak. To definitively answer if jetted AGN systematically emit >~100 TeV neutrinos: (1) we compiled the largest catalog of blazars and their optical light curves to date; and (2) we searched for a spatio-temporal correlation between these blazar light curves and IceCube’s first catalog of >~100 TeV neutrino events while assuming that neutrinos are expected at the brightest optical outbursts. Under this phenomenological assumption, we found that a global blazar-neutrino correlation cannot be confidently established, inline with the result of our previous study in the radio band. We estimated that fewer than ~8% of >~100TeV neutrino events came from major blazar outbursts, alluding to substantial contributions from other systems. In my talk, I will present this state-of-the-art correlation study and outlook for further searches with next generation of instruments.

Categorie: Aula: Seminario

maggio – novembre 2025 Mag – Nov 2025