BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CERN//INDICO//EN
BEGIN:VEVENT
SUMMARY:Exact cosmological models with a peculiar velocity field
DTSTART;VALUE=DATE-TIME:20180917T073000Z
DTEND;VALUE=DATE-TIME:20180917T080000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-24@cern.ch
DESCRIPTION:Speakers: SUSSMAN\, Roberto (ICN-UNAM)\nI examine two classes
of exact solutions of Einstein's equations describing matter-energy source
s in a non-comoving frame\, either within a single fluid or a two fluid ap
proach. These models can be used to test various assumptions on backreacti
on and to examine the observational effects of the Hubble flow.\n\nhttp://
th.if.uj.edu.pl/indico/event/8/session/3/contribution/24
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/session/3/contribution/24
END:VEVENT
BEGIN:VEVENT
SUMMARY:Preventing the Big Rip in a silent universe
DTSTART;VALUE=DATE-TIME:20180918T073000Z
DTEND;VALUE=DATE-TIME:20180918T080000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-26@cern.ch
DESCRIPTION:Speakers: MACLAURIN\, Colin (University of Queensland)\nThe 'B
ig Rip' is a proposed hypothetical end to the universe where the Hubble pa
rameter increases to infinity in a finite time. It assumes the universe co
ntains a fluid ('dark energy' say) with an equation of state state w\n\nht
tp://th.if.uj.edu.pl/indico/event/8/session/4/contribution/26
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/session/4/contribution/26
END:VEVENT
BEGIN:VEVENT
SUMMARY:ET tutorial/workshop
DTSTART;VALUE=DATE-TIME:20180920T120000Z
DTEND;VALUE=DATE-TIME:20180920T130000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-27@cern.ch
DESCRIPTION:Speakers: MACPHERSON\, Hayley (Monash University)\nhttp://th.i
f.uj.edu.pl/indico/event/8/contribution/27
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/contribution/27
END:VEVENT
BEGIN:VEVENT
SUMMARY:The distance - redshift relation in the inhomogeneous universe: im
proving perturbation theory
DTSTART;VALUE=DATE-TIME:20180918T093000Z
DTEND;VALUE=DATE-TIME:20180918T100000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-23@cern.ch
DESCRIPTION:Speakers: VILLA\, Eleonora (CFT PAN)\nWe consider an approxima
tion scheme aiming at accounting for the effect of non-linear inhomogeneit
ies in relativistic cosmology at all scales of interest: the perturbations
in the space-time metric are considered to be small\, but a different wei
ght is given to their first and second spatial derivatives\, taking into a
ccount that peculiar velocities - corresponding to first spatial derivativ
es - are small\, but allowing the spatial curvature and the density pertur
bations - corresponding to second spatial derivatives - to be large. We ap
ply this framework to light propagation and discuss the possible improveme
nt of our approach with respect to the standard perturbative description.\
n\nhttp://th.if.uj.edu.pl/indico/event/8/session/5/contribution/23
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/session/5/contribution/23
END:VEVENT
BEGIN:VEVENT
SUMMARY:The special case of the Stephani solution for the Universe with ac
celerated expansion
DTSTART;VALUE=DATE-TIME:20180919T093000Z
DTEND;VALUE=DATE-TIME:20180919T100000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-28@cern.ch
DESCRIPTION:Speakers: BORMOTOVA\, Iryna (Silesian University in Opava\, Cz
ech Republic)\, CHURILOVA\, Mariia (Dnipropetrovsk National University)\nW
e present the particular case of the Stephani solution for shear-free perf
ect fluid with uniform energy density and non-uniform pressure. Such model
s appeared last time as possible alternative to the consideration of the e
xotic forms of matter like dark energy that would cause the acceleration o
f the Universe expansion. These models are characterised by the spatial cu
rvature depending on time. We analyze the properties of the cosmological m
odel obtained on the basis of exact solution of the Stephani class and ado
pt it to the modern observational data. We show that despite of possible s
ingularities\, the model can describe the current stage of the Universe ev
olution. The spatial geometry of the model is investigated. Co-authors: Ma
riia Churilova\, Dr.\, Dnipropetrovsk National University\, Ukraine\, Elen
a Kopteva\, Dr.\, Silesian University in Opava\, Czech Republic.\n\nhttp:/
/th.if.uj.edu.pl/indico/event/8/session/7/contribution/28
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/session/7/contribution/28
END:VEVENT
BEGIN:VEVENT
SUMMARY:Vacuum initial data on the three-sphere from Killing vectors
DTSTART;VALUE=DATE-TIME:20180920T073000Z
DTEND;VALUE=DATE-TIME:20180920T080000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-29@cern.ch
DESCRIPTION:Speakers: SIMON\, Walter (University of Vienna)\nWe generate i
nitial data for vacuum spacetimes (possibly with cosmological constant) vi
a the conformal method\, with a three sphere or a ”three- donut” (the
product of a two-sphere with a circle) as "seed metrics". Our motivation c
omes from black-hole-lattice cosmology. However\, in contrast to known sch
emes for constructing corresponding data\, we do not allow for punctures\,
which prevents us from changing topology. On the other hand\, we include
the non-linear terms ("cosmological" and "momentum") in the Lichnerowicz e
quation. We discuss how theorems from differential geometry (Yamabe\, Obat
a\, Premoselli) guarantee or exclude the existence of suitable solutions o
f this equation. We consider two examples: As a warmup\, we recall the max
imal Kottler (="Schwarzschild de Sitter") data on the three-donut. We then
focus on the round three sphere where we take as momentum a transverse\,
trace-free tensor constructed algebraically out of certain pairs of the sp
here’s Killing vectors and their derivatives. This endows the sphere wit
h some "structure" - but not necessarily with black holes. This is joint w
ork with Robert Beig and Piotr Bizo\\'n.\n\nhttp://th.if.uj.edu.pl/indico/
event/8/session/8/contribution/29
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/session/8/contribution/29
END:VEVENT
BEGIN:VEVENT
SUMMARY:Inhomogeneous cosmological simulations with numerical relativity
DTSTART;VALUE=DATE-TIME:20180917T070000Z
DTEND;VALUE=DATE-TIME:20180917T073000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-1@cern.ch
DESCRIPTION:Speakers: MACPHERSON\, Hayley (Monash University)\nHigh-precis
ion cosmological surveys are due to deliver measurements accurate to the p
ercent level. In order to ensure we correctly interpret these data\, we ne
ed to be sure that our cosmological model is accurate. The current standar
d model assumes that the Universe is homogeneous and isotropic. These assu
mptions are valid at early times and on very large scales. On smaller scal
es\, these assumptions are called into question. Smaller-scale nonlinear s
tructures will affect light propagation\, and hence our observations. The
extent our observations will be affected can only be fully addressed with
numerical relativity. We use the Einstein Toolkit to perform cosmological
evolutions with full numerical relativity. I will present our results of a
veraging a truly inhomogeneous\, anisotropic matter distribution and how t
his compares to the equivalent FLRW model.\n\nhttp://th.if.uj.edu.pl/indic
o/event/8/session/3/contribution/1
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/session/3/contribution/1
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dark Matter from Backreaction?
DTSTART;VALUE=DATE-TIME:20180917T100000Z
DTEND;VALUE=DATE-TIME:20180917T103000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-3@cern.ch
DESCRIPTION:Speakers: VIGNERON\, Quentin (CRAL\, ENSL\, Université Lyon 1
)\nIn Inhomogeneous Cosmology\, restricting attention to an irrotational d
ust matter model\, backreaction arises in terms of the deviation of the av
eraged spatial scalar curvature from a constant-curvature model\, $\\mathc
al{W_D}$\, and the kinematical backreaction\, $\\mathcal{Q_D}$. The result
ing cosmological equations can be written in Friedmannian form featuring a
n effective scalar field in place of the backreaction\, called the morphon
field. A simple example for this morphon field is the class of scaling so
lutions where $\\mathcal{W_D}$ and $\\mathcal{Q_D}$ are assumed to follow
a power law of the volume scale factor $a_\\mathcal{D}$. The corresponding
exact solutions can describe models of effective quintessence\, arising w
ith the morphon\, but these and other models still assume the existence of
dark matter in addition to the known sources. The contribution from backr
eaction\, however\, can change its sign to mimic dark matter-like effects.
We here investigate the correspondence between the morphon field and fund
amental scalar field dark matter models\, in order to describe cosmologica
l dark matter as an effective phenomenon arising from kinematical backreac
tion and the averaged spatial curvature of the inhomogeneous Universe. We
further investigate the inverse problem by starting from exact scaling sol
utions and approximate solutions for structure formation and determine the
properties of the corresponding morphon field.\n\nhttp://th.if.uj.edu.pl/
indico/event/8/session/2/contribution/3
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/session/2/contribution/3
END:VEVENT
BEGIN:VEVENT
SUMMARY:The most massive virialized objects in the Universe
DTSTART;VALUE=DATE-TIME:20180918T070000Z
DTEND;VALUE=DATE-TIME:20180918T073000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-2@cern.ch
DESCRIPTION:Speakers: OSTROWSKI\, Jan (Centre de Recherche Astrophysique d
e Lyon)\nThe existence of the most massive virialized objects can be used
as a tool to study properties of the Universe\, such as the nature of grav
ity and dark sector\, as well as\, the Gaussianity of primordial density f
luctuations. In my talk I will show the predictions for the most massive o
bjects in the Universe using the silent universe model (Einstein field equ
ations with no rotation and energy transfer) and the scalar averaging form
alism with the Zel'dovich approximation serving as a closure condition. I
will present the cosmological mass function of galaxy clusters for both ca
ses and put them in the context of current and future astronomical sky sur
veys.\n\nhttp://th.if.uj.edu.pl/indico/event/8/session/4/contribution/2
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/session/4/contribution/2
END:VEVENT
BEGIN:VEVENT
SUMMARY:Expansion and topology dynamics in dust cosmology
DTSTART;VALUE=DATE-TIME:20180920T090000Z
DTEND;VALUE=DATE-TIME:20180920T093000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-5@cern.ch
DESCRIPTION:Speakers: BRUNSWIC\, Léo (CRAL\, ENSL\, Université Lyon 1)\n
In 2+1 Buchert's dust framework\, the Gauss-Bonnet Theorem allows us to id
entify the Euler characteristic with a mass of topological origin\, with p
ositive or negative sign. Even though this does not extend in a straightfo
rward manner to the 3+1 setting\, a Theorem of Mess extended by Bonsante a
nd Barbot suggest the insight extend to higher dimension. We explain how t
he Euler characteristic may evolve in a `sticky particle model': in dimens
ion 2+1\, a dust spacetime may be discretized to a flat spacetime with sin
gular lines (massive point-particles)\; these particles may collide and we
assume that at most one massive particle arises from the collision (massi
ve particles are `sticky'). Collisions may give rise to white/black hole w
hich change the topological type of the spacetime and\, thus\, the Euler c
haracteristic of its Cauchy-surfaces. In such a scenario\, Dark Energy ari
ses through the evolution of the Euler characteristic to strongly negative
values\, corresponding to on average negative spatial curvature.\n\nhttp:
//th.if.uj.edu.pl/indico/event/8/session/9/contribution/5
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/session/9/contribution/5
END:VEVENT
BEGIN:VEVENT
SUMMARY:Intrinsic average evolution of a general fluid in arbitrary foliat
ions
DTSTART;VALUE=DATE-TIME:20180917T090000Z
DTEND;VALUE=DATE-TIME:20180917T093000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-4@cern.ch
DESCRIPTION:Speakers: MOURIER\, Pierre (Centre de Recherche Astrophysique
de Lyon\, École Normale Supérieure de Lyon)\nProperties and dynamics of
an inhomogeneous Universe can be described through regional spatial averag
ing of scalar observables. In relativistic cosmology\, the resulting avera
ged quantities will depend on the choice of space-like hypersurfaces defin
ing the spatial slices of averaging. I will present a general averaging fr
amework that applies to any choice for such a foliation\, and the resultin
g effective evolution equations for a region of an arbitrary source fluid.
It combines a 3+1 "slicing" formalism used to define the averaging hypers
urfaces with the general 1+3 "threading" that defines the fluid flow. I wi
ll stress the interest of an averaging procedure that focusses as much as
possible on intrinsic properties of the fluid content. This helps avoiding
artificial dependencies in the choice of foliation. I will also present a
n example of foliation choices that are themselves built from the fluid fl
ow and that provide compact and transparent averaged evolution equations.\
n\nhttp://th.if.uj.edu.pl/indico/event/8/session/2/contribution/4
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/session/2/contribution/4
END:VEVENT
BEGIN:VEVENT
SUMMARY:ET tutorial/workshop
DTSTART;VALUE=DATE-TIME:20180917T133000Z
DTEND;VALUE=DATE-TIME:20180917T153000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-7@cern.ch
DESCRIPTION:Speakers: MACPHERSON\, Hayley (Monash University)\nhttp://th.i
f.uj.edu.pl/indico/event/8/contribution/7
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/contribution/7
END:VEVENT
BEGIN:VEVENT
SUMMARY:Roadmap for inhomogeneous cosmology and backreaction
DTSTART;VALUE=DATE-TIME:20180917T120000Z
DTEND;VALUE=DATE-TIME:20180917T130000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-6@cern.ch
DESCRIPTION:Speakers: ROUKEMA\, Boudewijn (Toruń Centre for Astronomy\, N
icolaus Copernicus University)\nhttp://th.if.uj.edu.pl/indico/event/8/cont
ribution/6
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/contribution/6
END:VEVENT
BEGIN:VEVENT
SUMMARY:Covariant and observer-independent approach to geometric optics in
GR
DTSTART;VALUE=DATE-TIME:20180918T090000Z
DTEND;VALUE=DATE-TIME:20180918T093000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-9@cern.ch
DESCRIPTION:Speakers: KORZYŃSKI\, Mikołaj (Center for Theoretical Physic
s\, Polish Academy of Sciences)\nI will present a covariant and observer-i
ndependent approach to geometric optics in GR. I will discuss how one can
calculate the parallax\, the image distortion and magnification and the po
sition drift\, including all GR effects\, of a distant source using biloca
l optical operators. The formalism can be applied to any metric and has po
tentially important applications to cosmology and relativistic astrophysic
s.\n\nhttp://th.if.uj.edu.pl/indico/event/8/session/5/contribution/9
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/session/5/contribution/9
END:VEVENT
BEGIN:VEVENT
SUMMARY:The decaying mode and the growing mode in the high order cosmologi
cal perturbation theory
DTSTART;VALUE=DATE-TIME:20180921T093000Z
DTEND;VALUE=DATE-TIME:20180921T100000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-11@cern.ch
DESCRIPTION:Speakers: SIKORA\, Szymon (Astronomical Observatory\, Jagiello
nian University)\nDuring this talk\, I will present the method of the cons
truction of the approximate solutions in the framework of the cosmological
perturbation theory in the order higher than two. I will restrict to the
synchronous gauge and impose the particular symmetry condition by demandin
g that the metric is invariant under every permutation of the spatial coor
dinates. In this setup\, I will show how to specify the metric functions s
o that the resulting energy-momentum tensor approximates the dust energy-m
omentum tensor. I will mention the results obtained with Krzysztof Głód
concerning the decaying mode and present the recent results dedicated to t
he growing mode.\n\nhttp://th.if.uj.edu.pl/indico/event/8/session/11/contr
ibution/11
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/session/11/contribution/11
END:VEVENT
BEGIN:VEVENT
SUMMARY:Extremal-foliations and foliation-(in)dependence of averaged quant
ities
DTSTART;VALUE=DATE-TIME:20180917T093000Z
DTEND;VALUE=DATE-TIME:20180917T100000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-10@cern.ch
DESCRIPTION:Speakers: HEINESEN\, Asta (University of Canterbury)\nWe inves
tigate extremal-foliations and foliation-(in)dependence of averaged space-
time quantities\, appearing in Buchert's scheme and generalisations hereof
. For this purpose we introduce a generalised window-function for spatial
hyper surface averaging\, and investigate variation of the associated hype
rsurface-scalar. Surprisingly we find that there are foliation-independent
statements to be made about certain physical integrated quantities. Howev
er\, most integrated/averaged quantities are\, not surprisingly\, foliatio
n dependent. We discuss methods for bounding the foliation dependence with
in a class of foliations\, and provide physical examples of when such a bo
und can be useful.\n\nhttp://th.if.uj.edu.pl/indico/event/8/session/2/cont
ribution/10
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/session/2/contribution/10
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gevolution hackathon
DTSTART;VALUE=DATE-TIME:20180918T120000Z
DTEND;VALUE=DATE-TIME:20180918T130000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-13@cern.ch
DESCRIPTION:Speakers: ROUKEMA\, Boudewijn (Toruń Centre for Astronomy\, N
icolaus Copernicus University)\nhttp://th.if.uj.edu.pl/indico/event/8/cont
ribution/13
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/contribution/13
END:VEVENT
BEGIN:VEVENT
SUMMARY:Reciprocity and symplecticity
DTSTART;VALUE=DATE-TIME:20180918T100000Z
DTEND;VALUE=DATE-TIME:20180918T103000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-12@cern.ch
DESCRIPTION:Speakers: UZUN\, Nezihe (Ústav teoretické fyziky MFF UK)\nRe
ciprocity relations in physics signal the existence of potentiality of a s
ystem. Maxwell-Betti reciprocity for virtual work in elasticity\, Onsager'
s reciprocity in thermodynamics or quantum mechanical reciprocity of the r
eceived signal all state that the observables are unchanged when the input
and output agents are traversed. Those distinct systems share a similar p
roperty: they are defined under some well-defined potential. The work we p
resent here grew out of questioning what kind of potentiality Etherington'
s distance reciprocity in relativity corresponds to. The outcome of such a
n investigation turns out to be a symplectic phase space reformulation of
first order geometric optics in relativity.\n\nhttp://th.if.uj.edu.pl/indi
co/event/8/session/5/contribution/12
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/session/5/contribution/12
END:VEVENT
BEGIN:VEVENT
SUMMARY:Inhomogeneous Cosmology Whitepaper
DTSTART;VALUE=DATE-TIME:20180919T070000Z
DTEND;VALUE=DATE-TIME:20180919T073000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-15@cern.ch
DESCRIPTION:Speakers: ROUKEMA\, Boudewijn (Toruń Centre for Astronomy\, N
icolaus Copernicus University)\nhttp://th.if.uj.edu.pl/indico/event/8/sess
ion/6/contribution/15
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/session/6/contribution/15
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gevolution hackathon
DTSTART;VALUE=DATE-TIME:20180918T133000Z
DTEND;VALUE=DATE-TIME:20180918T153000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-14@cern.ch
DESCRIPTION:Speakers: ROUKEMA\, Boudewijn (Toruń Centre for Astronomy\, N
icolaus Copernicus University)\nhttp://th.if.uj.edu.pl/indico/event/8/cont
ribution/14
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/contribution/14
END:VEVENT
BEGIN:VEVENT
SUMMARY:Black Hole Lattices as Exact\, Inhomogeneous Cosmological Models
DTSTART;VALUE=DATE-TIME:20180920T070000Z
DTEND;VALUE=DATE-TIME:20180920T073000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-17@cern.ch
DESCRIPTION:Speakers: DURK\, Jessie (Queen Mary University of London)\nBla
ck hole lattices are an interesting subset of inhomogeneous cosmologies. T
hese are exact\, fully-relativistic treatments of universes with a discret
ised matter content. We generalise existing lattices to include a cosmolog
ical constant and structure formation. For each new generalisation\, we fi
nd a common behaviour of tending towards FLRW-like as the number of masses
is increased\, and for the addition of structures\, we investigate the ef
fect of gravitational interaction energies between clustered masses. When
intra-cluster energies are taken into account\, the discrepancy between th
e scales of lattice and FLRW cosmologies can be alleviated. We also discus
s preliminary results of constructing black hole lattices using a simple s
calar-tensor theory of gravity and find several solutions – some that ad
mit sensible cosmologies and others that do not\, which may place constrai
nts on particular solutions.\n\nhttp://th.if.uj.edu.pl/indico/event/8/sess
ion/8/contribution/17
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/session/8/contribution/17
END:VEVENT
BEGIN:VEVENT
SUMMARY:Blueshifted light from the last-scattering epoch
DTSTART;VALUE=DATE-TIME:20180919T073000Z
DTEND;VALUE=DATE-TIME:20180919T080000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-16@cern.ch
DESCRIPTION:Speakers: KRASIŃSKI\, Andrzej (N. Copernicus Astronomical Cen
ter\, Polish Academy of Sciences)\nSome light rays emitted from the Big Ba
ng (BB) in Lemaitre - Tolman (L-T) and Szekeres (Sz) models reach all obse
rvers with an infinite blueshift. This happens when at the emission point
the BB function t_B(r) has nonzero derivative and the ray propagates radia
lly (in L-T) or along one of two preferred directions (in Sz). Consequentl
y\, some rays emitted during the last scattering period should be reaching
us with a finite blueshift. This is a prediction of general relativity\,
which is an otherwise well-tested theory\, so it should be investigated fo
r its consequences for observations. This author recently proposed that bl
ueshifted rays are observed as gamma-ray bursts (GRBs). In four consecutiv
e papers it was shown that (1) L-T-based models of GRB sources successfull
y account for the energies of the GRBs\, the large distances to them\, the
ir multitude\, and for the existence of the afterglows (but not for the du
rations of the GRBs and of the afterglows and for their [hypothetical] col
limation into narrow jets)\; (2) In Sz-based models large blueshifts may a
rise only along two opposite directions\, so the collimation is immediatel
y accounted for\; (3) A Sz model generates a stronger blueshift than an L-
T model with the same BB profile\; (4) The short duration of the GRBs is a
ccounted for if the blueshifted ray\, on its way to the present observer\,
passes through another Sz region\, where it undergoes the cosmic drift (i
.e. a deflection by a time-dependent angle). The last two remaining proble
ms are (i) to account for the measured durations of the afterglows and (ii
) to make the angular diameters of the sources in the model compatible wit
h the limits imposed by observations. Work on these is in progress.\n\nhtt
p://th.if.uj.edu.pl/indico/event/8/session/6/contribution/16
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/session/6/contribution/16
END:VEVENT
BEGIN:VEVENT
SUMMARY:Backreaction of gravitational and scalar waves
DTSTART;VALUE=DATE-TIME:20180921T100000Z
DTEND;VALUE=DATE-TIME:20180921T103000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-19@cern.ch
DESCRIPTION:Speakers: SZYBKA\, Sebastian (Jagiellonian University)\nWithin
the Green-Wald backreaction framework\, one may calculate the effect of s
mall scale inhomogeneities on the global structure of a background spaceti
me. I will discuss properties of a background spacetime representing cylin
drically symmetric high frequency gravitational and scalar standing waves.
\n\nhttp://th.if.uj.edu.pl/indico/event/8/session/11/contribution/19
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/session/11/contribution/19
END:VEVENT
BEGIN:VEVENT
SUMMARY:Strict solutions in the linear theory of cosmological perturbation
s up to second order
DTSTART;VALUE=DATE-TIME:20180919T090000Z
DTEND;VALUE=DATE-TIME:20180919T093000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-18@cern.ch
DESCRIPTION:Speakers: GŁÓD\, Krzysztof (Astronomical Observatory of the
Jagiellonian University)\nWe consider scalar perturbations of the spatiall
y flat Friedmann--Lemaitre cosmological model. We formulate conditions for
the metric functions under which basic gauge-invariant kinematic and dyna
mic fields of the perturbed model vanish at the first order of the linear
perturbation theory. Then we combine these conditions to construct especia
lly interesting perturbed models with specific properties. We particularly
study the models with inhomogeneities characterized by the perfect fluid
energy-momentum tensor and the models with inhomogeneities which behave mo
notonically with time. Finally\, we perform the strict extension of the si
mplest cases of the considered models to the second order. We determine ne
cessary assumptions for this development and present explicit solutions fo
r the metric functions.\n\nhttp://th.if.uj.edu.pl/indico/event/8/session/7
/contribution/18
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/session/7/contribution/18
END:VEVENT
BEGIN:VEVENT
SUMMARY:Black holes on cosmological background
DTSTART;VALUE=DATE-TIME:20180920T093000Z
DTEND;VALUE=DATE-TIME:20180920T100000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-30@cern.ch
DESCRIPTION:Speakers: JALUVKOVA\, Pavlina (JINR Dubna\, Russia\;Silesian u
niversity in Opava\, Czech Republic)\nIn this work\, we propose the way to
construct the model of the cosmological black hole in the dust-filled uni
verse on the basis of the exact solution to the Einstein equations of the
Lemaitre-Tolman-Bondi class. We have found such solution as a particular c
ase of Tolman solution with the arbitrary functions chosen in a special wa
y such that the solution includes both the Schwarzschild and Friedmann sol
utions as its natural limiting cases. We have analyzed the properties of t
he obtained solution for the three types of spatial curvature and built th
e R-T-structure of the resulting spacetime\, showing the horizons and sing
ularities of the solution. We have demonstrated that in the center of symm
etry of the obtained spacetime there is a region where the black hole is s
ituated. The question of avoiding the shell-crossing in the model was solv
ed. The trajectories of the test particles were built near the black hole
for both comoving and distant observer. Although the metric for the distan
t observer was non-static\, we have obtained the physically realistic pict
ure of motion of the test particles around the black hole. From our analys
is it follows that within the second order accuracy one will obtain the us
ual results\, but cosmological corrections will appear in the next order.
And as far as the obtained solution is exact the cosmological corrections
to the Schwarzschild asymptotic may be found analytically up to any order
of accuracy.\n\nhttp://th.if.uj.edu.pl/indico/event/8/session/9/contributi
on/30
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/session/9/contribution/30
END:VEVENT
BEGIN:VEVENT
SUMMARY:Maxima ctensor tutorial
DTSTART;VALUE=DATE-TIME:20180919T133000Z
DTEND;VALUE=DATE-TIME:20180919T153000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-36@cern.ch
DESCRIPTION:Speakers: ROUKEMA\, Boudewijn (Toruń Centre for Astronomy\, N
icolaus Copernicus University)\nhttp://th.if.uj.edu.pl/indico/event/8/cont
ribution/36
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/contribution/36
END:VEVENT
BEGIN:VEVENT
SUMMARY:Maxima tutorial
DTSTART;VALUE=DATE-TIME:20180919T120000Z
DTEND;VALUE=DATE-TIME:20180919T130000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-35@cern.ch
DESCRIPTION:Speakers: SIKORA\, Szymon (Astronomical Observatory\, Jagiello
nian University)\nhttp://th.if.uj.edu.pl/indico/event/8/contribution/35
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/contribution/35
END:VEVENT
BEGIN:VEVENT
SUMMARY:First integrals in the cosmological perturbation equations
DTSTART;VALUE=DATE-TIME:20180921T090000Z
DTEND;VALUE=DATE-TIME:20180921T093000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-34@cern.ch
DESCRIPTION:Speakers: WOSZCZYNA\, Andrzej (Politechnika Krakowska)\nDarbou
x transformations convert the cosmological perturbation equations to the f
orm of the d'Alembert equation. Consequently\, the Noether constants (the
conserved hamiltonian for instance) can be easily found. The exact form of
the Darboux transformation\, however\, is the subject of guess (Field She
pley 1968)\, what strongly limitates the effectivness of the method. In th
e present talk we introduce an algorithm for finding the conserved quantit
ies for perturbations. We employ the Darboux algebraic method for dynamica
l systems with the polynomial right hand side. We use the computer algebra
. A simple package for Wolfram Mathematica is written.\n\nhttp://th.if.uj.
edu.pl/indico/event/8/session/11/contribution/34
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/session/11/contribution/34
END:VEVENT
BEGIN:VEVENT
SUMMARY:Roadmap for inhomogeneous cosmology and backreaction/summary
DTSTART;VALUE=DATE-TIME:20180921T133000Z
DTEND;VALUE=DATE-TIME:20180921T143000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-33@cern.ch
DESCRIPTION:Speakers: BUCHERT\, Thomas (Université Lyon 1)\nhttp://th.if.
uj.edu.pl/indico/event/8/contribution/33
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/contribution/33
END:VEVENT
BEGIN:VEVENT
SUMMARY:ET tutorial/workshop
DTSTART;VALUE=DATE-TIME:20180921T120000Z
DTEND;VALUE=DATE-TIME:20180921T130000Z
DTSTAMP;VALUE=DATE-TIME:20190821T050225Z
UID:indico-contribution-8-32@cern.ch
DESCRIPTION:Speakers: MACPHERSON\, Hayley (Monash University)\nhttp://th.i
f.uj.edu.pl/indico/event/8/contribution/32
LOCATION:
URL:http://th.if.uj.edu.pl/indico/event/8/contribution/32
END:VEVENT
END:VCALENDAR