From raffaella.schneider at uniroma1.it  Tue Mar  1 19:25:35 2022
From: raffaella.schneider at uniroma1.it (Raffaella Schneider)
Date: Tue, 1 Mar 2022 19:25:35 +0100
Subject: [astroseminar@Sapienza] Gentle reminder for the next QUID ULTRA
 colloquium by Felix Aharonian, 2 March at 16:30 in Aula Conversi
Message-ID: <0F56F78D-FA04-4413-99E7-EF6A5E24DD48@uniroma1.it>

Please accept my apologies if you receive this more than once.


Dear Students and Colleagues,

this is to gently remind you that the next online colloquium of the series: 

Quid Ultra? Frontiers and Controversies in Astrophysics 

will be tomorrow, March 2 at 16:30 by Felix Aharonian (Dublin Institute for Advanced Studies and Max-Planck-Institute for Nuclear Physics Heidelberg) 
in aula Conversi, Dipartimento di Fisica, Sapienza Universit? 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.

You can find all the details below and the link:  https://www.quidultra.it <https://www.quidultra.it/>

Looking forward to seeing you soon, 

Raffaella Schneider (on behalf of the SOC)
  
Prof. Raffaella Schneider
Dipartimento di Fisica "G. Marconi?
Senior Fellow, Scuola Superiore di Studi Avanzati Sapienza
Sapienza, Universit? di Roma
P.le A. Moro 2, 00185 Roma, Italy
raffaella.schneider at roma1.infn.it <mailto:raffaella.schneider at roma1.infn.it>



2nd QUID ULTRA colloquium 2022

March 2 2022 at 16:30, aula Conversi, Dipartimento di Fisica, Sapienza Universit? 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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From paolo.pani at uniroma1.it  Wed Mar  9 17:06:48 2022
From: paolo.pani at uniroma1.it (Paolo Pani)
Date: Wed, 9 Mar 2022 17:06:48 +0100
Subject: [astroseminar@Sapienza] Gravity-theory seminar: March 10th 4pm
 Conversi: Laura Sberna (AEI) - The calm after the storm: the black hole
 ringdown beyond linear perturbation theory
Message-ID: <CADjeKwAMn_kJnZbxyyafY9g0-3ikNqtKXOqBQ-4FiqsQXNT64Q@mail.gmail.com>

Seminar announcement:

*Speaker: *Laura Sberna (AEI, Potsdam)
*Title: *The calm after the storm: the black hole ringdown beyond linear
perturbation theory

*Date:*  Thursday, Mar 10th at 4pm CET
*Location:* Conversi Hall & Zoom (see below)


*Abstract:  *
When a binary merges to form a single black hole, the merger product emits
a final burst of gravitational waves known as the ?ringdown?. Ringdowns are
currently being observed with LIGO and Virgo, and will be even stronger in
future detectors like the Einstein Telescope or LISA. Observations of black
hole ringdowns can be used to characterize binary merger remnants, and are
particularly suited to test general relativity.
So far, analyses of the ringdown have assumed *linear* black hole
perturbation theory. In this talk, I will explore *nonlinear* effects
during the ringdown, which could potentially spoil (or enhance) ringdown
analysis. I will focus on one nonlinear process, which we call
"absorption-induced
mode excitation? or AIME.  I will use numerical and analytic techniques to
explore this process first in a toy model in anti-de Sitter, and then in
asymptotically-flat Schwarzschild black holes. Our results so far indicate
that nonlinear effects could play a role in the interpretation of current
and future gravitational wave observations.

The Zoom link is
https://uniroma1.zoom.us/j/86496887581?pwd=aVVRRXd2Z3pBbGZObVhEUjVZWjc0UT09
ID meeting: 864 9688 7581
Passcode: cCUG8j

Cheers,
Paolo

-- 
Paolo Pani
Associate Professor
ERC StG Fellow, DarkGRA project
Junior Fellow, Scuola Superiore di Studi Avanzati Sapienza

Physics Department (Marconi Building), 3rd floor, room 334
Sapienza University of Rome
Piazzale Aldo Moro 5 - 00185 Rome (Italy)
+39 06 4991 4472 (int 24472)
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From raffaella.schneider at uniroma1.it  Thu Mar 31 16:13:21 2022
From: raffaella.schneider at uniroma1.it (Raffaella Schneider)
Date: Thu, 31 Mar 2022 16:13:21 +0200
Subject: [astroseminar@Sapienza] Third colloquium of the 2022 program QUID
 ULTRA by Georges Meynet (University of Geneva) on Wednesday April 6 at
 16:30
Message-ID: <7B7C9B29-AE59-481E-A458-E99F84D6FE80@uniroma1.it>

Dear Colleagues,

we are pleased to announce that the third colloquium of the 2022 program QUID ULTRA? Frontiers and Controversies in Astrophysics, 
will be on wednesday, April 6 2022 at 16:30 by Georges Meynet (University of Geneva).

Title and abstract are attached below. 

The seminar will be held remotely by the speaker through the following 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
 

The program QUID ULTRA? Frontiers and Controversies in Astrophysics is a series of monthly prestigious colloquia that will be 
running from early February till October 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)

????????????????
April 6 2022, 16:30

Speaker: Georges Meynet (University of Geneva)

Title: Stars at the Extreme: First Stars, Spinstars and Supermassive stars

Abstract:
The presentation will focus on stars at some extreme either from the point of view of their mass (supermassive stars), rotation (spinstars) or initial composition 
(Pop III stars). The talk will begin by a general overview of the main challenges faced by the modeling of massive stars with a special focus on the 
transport processes in convective and radiative zones. Then the presentation will continue discussing recent results about the binary statistics of Pop III 
populations, the chemical and radiative feedback of Pop III stars, the evolution of very massive stars i.e. stars with masses between 150 and 300 solar 
masses at different metallicities addressing the question of the progenitor of Pair Instability supernovae and the limits of the mass domain for the 
black hole mass gap. Finally, new models for the formation of supermassive stars that are candidates as seeds for the formation of supermassive black holes 
at high redshift will be presented.

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
????????????????

Prof. Raffaella Schneider
raffaella.schneider at uniroma1.it
Dipartimento di Fisica 
Senior Fellow Scuola Superiore di Studi Avanzati Sapienza
Sapienza Universit? 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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