Dr. Asaf Pe’er
University College Cork (Ireland), Bar-Ilan Universtiy (Israel)
GRBs, Cosmic rays and shock waves
Abstract:
The acceleration site of ultra-high energy cosmic rays is still an open question despite extended research.
Over 20 years ago it was proposed that GRBs are good candidates. However, data of GRB prompt emission spectra at the different bands can be used to put strong constraints on the physical conditions of the outflow. I will show that the physical conditions during the GRB prompt emission do not enable the acceleration of particles to ultra-high energies, both within the frames of the synchrotron and the photospheric emission models. I will show that this is the case also for low luminosity (ll) GRBs, such as GRB060218.
(If time permits) I will discuss some recent results on diffusive shock acceleration (DSA) theory. I will describe a new model for particle acceleration in arbitrarily turbulent magnetic field, which bridges the gap between the very weak and strong turbulence regimes. I will discuss the validity and limitations of the “Bohm”-type diffusion model.
Location: 31 Fitzwilliam Place
Upcoming seminars:
https://www.dias.ie/2018/10/23/astronomy-and-astrophysics-seminar-schedule-2019/(opens in a new tab)
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Posted: 20th March 2019 by Rebeca Garcia
2019-03-27, 15:00: Dr. Asaf Pe’er (University College Cork (Ireland), and Bar-Ilan University (Israel))
Dr. Asaf Pe’er
University College Cork (Ireland), Bar-Ilan Universtiy (Israel)
GRBs, Cosmic rays and shock waves
Abstract:
The acceleration site of ultra-high energy cosmic rays is still an open question despite extended research.
Over 20 years ago it was proposed that GRBs are good candidates. However, data of GRB prompt emission spectra at the different bands can be used to put strong constraints on the physical conditions of the outflow. I will show that the physical conditions during the GRB prompt emission do not enable the acceleration of particles to ultra-high energies, both within the frames of the synchrotron and the photospheric emission models. I will show that this is the case also for low luminosity (ll) GRBs, such as GRB060218.
(If time permits) I will discuss some recent results on diffusive shock acceleration (DSA) theory. I will describe a new model for particle acceleration in arbitrarily turbulent magnetic field, which bridges the gap between the very weak and strong turbulence regimes. I will discuss the validity and limitations of the “Bohm”-type diffusion model.
Location: 31 Fitzwilliam Place
Upcoming seminars:
https://www.dias.ie/2018/10/23/astronomy-and-astrophysics-seminar-schedule-2019/(opens in a new tab)
Category: Seminars
...obituaries of prominent individuals The manuscript has been preserved in the @Library_RIA since 1883. (3/3) @HistFest #DIASdiscovers #connacht #books
The Annals of Connacht is a vellum manuscript that was written in the mid-16th century. The contents were derived from older annals compiled for the O’Conors of the Connacht and contain an annual record of significant events over 320 years, and... (2/3)
Date: 19 October 1944 Paper: The Irish Press Synopsis: DIAS has been publishing books since it's founding. One such early publication is the edited manuscript of the Annals of Connacht (Annála Connacht) which was edited for the first time by Martin Freeman of DIAS. (1/3)
This work was to help towards the preservation of the Irish Language, to maintain it's continuity with the past, and was to become a resource for teachers to check pronunciation #DIASdiscovers #Irish #Irishlanguage #CelticStudies #Gaelic
The researchers used the International Phonetic Alphabet, slightly modified to represent vowels and consonants of living speech. At that time there were concerns over the deterioration of the Irish language due to the "overpowering influence of English"
Date: 02 June 1943 Paper: The Irish Press Synopsis: In 1943, a phonetic investigation led by Brian Ó Cuív, Risteárd B. Breathnach and Tomás de Bhaldraithe of DIAS would begin the first systematic scientific recording of the varied sounds of modern Gaelic speech.
Happy Birthday! twitter.com/thecelticist/s…
The papers were 1) Affine Field Theory: conservation identitites and relation to Weyl and Eddington 2)The Union of the three fundamental fields (Gravitation, Menson, Electromagnetism) Which went on to secure worldwide acclaim. #DIASdiscovers
Date: 01 December 1943 Paper: The Irish Press Headline: Two Papers by Dr. Schroedinger Synopsis: 1943 was a busy year for Schroedinger. Not only did he deliver the "What is Life?" Lectures in @tcddublin in February in November he delivered two papers in the @RIAdawson (1/2)
Available to buy on the DIAS bookshop: books.dias.ie/index.php?main… (5/5) #DIASdiscovers #celtic #studies #twopatricks
"In the lives of St. Patrick, the two saints are invariably fused into one", said Prof. O'Rahilly in his lecture. The lecture was a condensation from O’Rahilly’s book “The two Patricks: a lecture on the history of Christianity in fifth-century Ireland”. (4/5)
He was known by his first name Patricius, which in later times would lead to confusion as he was succeeded by another apostle of the same name (Saint Patrick or Patricius in Latin). (3/5)
He spoke on "Palladius and Patrick". Palladius was the first bishop of the Christians of Ireland. (2/5)
Date: 21st March 1942 Paper: The Irish Press Headline: Palladius and Patrick | School Of Celtic Studies Lecture Synopsis: The first public lecture under the auspices of the School of Celtic Studies was delivered in Trinity College by Professor T. F. O'Rahilly in 1942. (1/5)
As part of our ongoing participation in the @HistFest we decided to take a look into the Irish Newspaper Archives and see where DIAS made it into print over the last 80 years. There were so many articles, the hardest part was selecting what we would post. We hope you enjoy!
@AReillyFailte @CultureNight @VisitDublin Thanks Antoinette! Glad you enjoyed 😊