[astroseminar at Sapienza] Announcement of the next QUID ULTRA colloquium by Felix Aharonian, Wednesday March 2 at 16:30, Aula Conversi, Sapienza University

[Raffaella Schneider]

Dear Colleagues,

we are pleased to announce that the second colloquium of the 2022 program QUID ULTRA? Frontiers and Controversies in Astrophysics, 
will be by Felix Aharonian (Dublin Institute for Advanced Studies and Max-Planck-Institute for Nuclear Physics Heidelberg) on Wednesday, March 2 2022 at 16:30
in aula Conversi, Dipartimento di Fisica, Sapienza Università di Roma. Title and abstract are attached below. 

It will be possible to follow the seminar remotely via the zoom link:
https://uniroma1.zoom.us/j/81122901013?pwd=M1hnRHRXZkEyeW1QMFlPQ2FXa0dNZz09 <https://uniroma1.zoom.us/j/81122901013?pwd=M1hnRHRXZkEyeW1QMFlPQ2FXa0dNZz09>
 
ID riunione: 811 2290 1013
Passcode: 686688
 
For people coming from outside the Campus, please make sure to fill the google form for guests and visitors that you will need to show at the main campus gate:
https://www.uniroma1.it/en/notizia/covid-19-phase-2-procedures-students-staff-and-guests <https://www.uniroma1.it/en/notizia/covid-19-phase-2-procedures-students-staff-and-guests>
and to be ready to show your green pass.

The program QUID ULTRA? Frontiers and Controversies in Astrophysics is a series of monthly prestigious colloquia that will be 
running from early February till December 2022. This initiative has been funded by Sapienza University with the co-sponsorship of 
INAF/Astronomical Observatory of Rome and of the joint PhD program in Astronomy, Astrophysics and Space Science of Sapienza, 
Tor Vergata University and INAF.

Looking forward to seeing you soon, 

Raffaella Schneider (on behalf of the SOC)

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March 2 2022 at 16:30, aula Conversi, Dipartimento di Fisica, Sapienza Università di Roma

Speaker: Felix Aharonian (Dublin Institute for Advanced Studies and Max-Planck-Institute for Nuclear Physics Heidelberg)

Title: PeVatrons and the "Century-old-Mistery" of Galactic Cosmic Rays

Abstract:
Despite the recent advances in Cosmic Ray studies, the origin of Galactic Cosmic Rays (CRs) is still considered a "century-old mystery" - we do not know yet which sources contribute to CR fluxes measured in the Earth's vicinity. Identifying the major CR contributors with astronomical source populations is one of the highest priorities of the field. The best carriers of information about CR factories are gamma-rays and neutrinos - the only stable and neutral secondary products of CR interactions pointing to the CR production sites. The recent years' outstanding achievement of gamma-ray astronomy was the discovery of TeV gamma-radiation from SNRs generally supporting the SNR paradigm of the origin of Galactic CRs. On the other hand, the lack of the extension of gamma-ray spectra of young SNRs well beyond 10 TeV raises doubts about their ability to contribute to the highest energy galactic CR spectrum in the so-called "knee" region above 1 PeV. Meanwhile, the ultra-high-energy (UHE; E> 100 TeV) gamma-ray observations of the clusters of young massive stars demonstrate mounting evidence of these objects (and related superbubbles) being prime contributors to Galactic CRs at PeV energies. I will discuss these observations in the context of the concept of "Young Stars versus Dead Stars". The hunt for CR PeVatrons cannot be reduced merely to the identification of the sources contributing to the local "CR fog". The term 'cosmic rays' has broader implications; after matter, radiation and magnetic fields, the relativistic nonthermal plasma constitutes the fourth substance of the observable Universe. The localisation and exploration of physical conditions and processes in these extreme CR factories, independent of their relative contributions to the 'CR fog', is a fundamental issue in its own right. I will highlight the recent exciting achievements of UHE gamma-ray astronomy in elucidating the cites of extreme CR accelerators in the Milky Way and discuss the implications of the discovery of a large number of CR PeVatrons by the LHAASO collaboration.

Join Zoom Meeting
https://uniroma1.zoom.us/j/81122901013?pwd=M1hnRHRXZkEyeW1QMFlPQ2FXa0dNZz09 <https://uniroma1.zoom.us/j/81122901013?pwd=M1hnRHRXZkEyeW1QMFlPQ2FXa0dNZz09>
 
ID riunione: 811 2290 1013
Passcode: 686688
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Prof. Raffaella Schneider
raffaella.schneider at uniroma1.it
Dipartimento di Fisica 
Senior Fellow Scuola Superiore di Studi Avanzati Sapienza
Sapienza Università di Roma
P.le A. Moro 2, 00185 Roma, Italy
Phone: +39 06 4991 4312
Skype: raffasch
Zoom: https://uniroma1.zoom.us/j/86080015153?pwd=dlV1eVNsS0xwazlMWTVZV05YeXZyUT09



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