<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8">
</head>
<body bgcolor="#FFFFFF" text="#000000">
Dear colleagues,<br>
<br>
this week we have a busy schedule, two seminars at the Department of
Physics and one seminar at the Department of Mathematics, in
chronological order:<br>
<br>
<b>Tuesday</b> (April 18th), <b>A-201 </b>(Dept. of Math.), <b>16:00h</b><br>
Speaker: <b>Predrag Cvitanović</b><br>
(Center for Nonlinear Science, Georgia Tech, Atlanta, USA)<br>
<br>
Title: <b>Is space time? A spatiotemporal theory of transitional
turbulence</b><br>
<br>
Abstract: Recent advances in fluid dynamics reveal that the
recurrent flows<br>
observed in moderate Reynolds number turbulence result from close<br>
passes to unstable invariant solutions of Navier-Stokes equations.<br>
By now hundreds of such solutions been computed for a variety of<br>
flow geometries, but always confined to small computational domains<br>
(minimal cells).<br>
<br>
The 2016 Gutkin and Osipov paper on many-particle quantum chaos<br>
opens a path to determining such solutions on spatially infinite<br>
domains. Flows of interest (pipe, channel flows) often come<br>
equipped with D continuous spatial symmetries. If the theory is<br>
recast as a (D+1)-dimensional space-time theory, the space-time<br>
invariant solutions are (D+1)-tori (and not the 1-dimensional<br>
periodic orbits of the traditional periodic orbit theory). The<br>
symbolic dynamics is likewise (D+1)-dimensional (rather than a<br>
single temporal string of symbols), and the corresponding zeta<br>
functions should be sums over tori, rather than 1-dimensional<br>
periodic orbits. In this theory there is no time, there is only a<br>
repertoire of admissible spatiotemporal patterns.<br>
<br>
-----------------------------------------------------------------------------------------------------------------<br>
<br>
<b>Wednesday</b> (April 19th), <b>F-201</b>, <b>11:00h</b><br>
Speaker: <b>Petar Mimica</b><br>
(Departament d’Astronomia i Astrofísica, Universitat de Valencia,
Spain)<br>
<br>
Title: <b>A theoretical study of magnetic fields and emitting
particles in blazar jets</b><br>
<br>
Abstract: Blazars are compact active galactic nuclei and sources of<br>
broadband emission whose relativistic jet presumably points directly<br>
towards us. They are among the most energetic sources in the
universe<br>
and are a subject of very intense research.<br>
I will present the results of an eight-year theoretical study that
tried<br>
to understand magnetic field strength and the emitting particle<br>
distribution in blazar jets. We developed an efficient numerical
code<br>
based on a sophisticated theoretical model and are able to produce<br>
multiwavelength blazar flares with arbitrary magnetic field
strengths.<br>
We show quantitatively to what extent the magnetic field strength
and<br>
the proportion of the non-thermal particles have an influence on the<br>
spectral features. Furthermore, we show how our modeling can be
applied<br>
to attempt to explain properties of the sample of gamma-ray blazars<br>
observed by Fermi, as well as the existence of different blazar
subclasses.<br>
<br>
-----------------------------------------------------------------------------------------------------------------<br>
<br>
<b>Thursday</b> (April 20th), <b>F-201</b>, <b>15:00h</b><br>
Speaker: <b>Maria-Rosa Cioni</b><br>
(Leibniz-Institut für Astrophysik Potsdam (AIP), Germany)<br>
<br>
Title: <b>A modern view of the Magellanic Clouds</b><br>
<br>
Abstract: The Magellanic Clouds are our nearest neighbouring
galaxies interacting<br>
with each other and with the Milky Way. They represent an early
stage of a<br>
minor merger event. They have been surveyed across the wavelength<br>
spectrum for many decades, but there are still many things to
understand<br>
about them. In this presentation, I will focus on near-infrared<br>
observations from the VISTA survey of the Magellanic Clouds system
(VMC)<br>
highlighting the most recent results. This is a photometric
large-scale<br>
project that started at ESO in 2009 and that will be completed
within the next few years. <br>
The main goals are to recover the star formation history and the
three-dimensional<br>
geometry of the system with unprecedented spatial accuracy, but the
data<br>
have a wide range of applications that extend to distant quasars. I
will<br>
also present these investigations in the context of future projects.<br>
<br>
-----------------------------------------------------------------------------------------------------------------<br>
<br>
Best regards,<br>
Ivica Smolić<br>
<br>
</body>
</html>