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BEGIN:VEVENT
SUMMARY:.
DTSTART;VALUE=DATE-TIME:20150909T103000Z
DTEND;VALUE=DATE-TIME:20150909T105000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090831@indico.cern.ch
DESCRIPTION:https://indico.cern.ch/event/438475/contributions/1090831/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090831/
END:VEVENT
BEGIN:VEVENT
SUMMARY:The bispectrum of relativistic galaxy number counts
DTSTART;VALUE=DATE-TIME:20150910T153000Z
DTEND;VALUE=DATE-TIME:20150910T155000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090892@indico.cern.ch
DESCRIPTION:Speakers: Giovanni Marozzi (Universite de Geneve\, Switzerland
)\nIn this talk\, I will present the evaluation of the galaxy number count
s to second order in cosmological perturbation theory in the Poisson gauge
. The calculation is performed using an innovative approach based on the r
ecently proposed ”geodesic light-cone” gauge\, which allows us to dete
rmine the number counts in a purely geometric way. To conclude\, I will pr
esent the numerical results for the leading non-linear and relativistic co
ntributions to the number counts bispectrum\, comparing them with the usua
l term from weakly non-linear Newtonian gravitational clustering and showi
ng how to neglect integrated relativistic terms can bring significant bias
.\n\nhttps://indico.cern.ch/event/438475/contributions/1090892/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090892/
END:VEVENT
BEGIN:VEVENT
SUMMARY:How much useful cosmological information can we capture beyond the
linear regime of structure formation?
DTSTART;VALUE=DATE-TIME:20150910T122000Z
DTEND;VALUE=DATE-TIME:20150910T124000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090966@indico.cern.ch
DESCRIPTION:Speakers: Julien Carron (University of Sussex\, United Kingdom
)\nDuring the nonlinear evolution from Gaussian initial conditions\, Fouri
er modes of the cosmological matter density field gradually develop statis
tical dependence. A precise understanding of this cosmic (co)variance is e
ssential for the ultimate success of the ambitious upcoming wide-field sur
veys targeting cosmic acceleration or modified theories of gravity. I will
discuss the dynamics of the information within the dark matter field and
how its affects the power spectrum\, and implications for cosmological par
ameter inference. I’ll show how to design from first principles simple y
et efficient analysis of the matter field\, that eventually must rely on a
non-linear transformation of the field. These transformations such as the
logarithmic transformation and its generalization the A* transformation a
re typically much better tracers of the linear density and recover up to a
factor of a few more information.\n\nhttps://indico.cern.ch/event/438475/
contributions/1090966/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090966/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Theoretical Predictions of Large Scale Clustering in the Lyman-alp
ha Forest
DTSTART;VALUE=DATE-TIME:20150908T151000Z
DTEND;VALUE=DATE-TIME:20150908T153000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090893@indico.cern.ch
DESCRIPTION:Speakers: Agnieska Cieplak (Brookhaven National Laboratory\, U
nited States)\nWith the recent progress of Lyman-alpha forest power spectr
um\nmeasurements\, understanding of the bias between the measured flux and
\nthe underlying matter power spectrum is becoming crucial to the\npercent
level cosmological interpretation of these measurements.\nPrevious theore
tical studies of this bias have used N-body and\nhydro-PM simulations and
inferred large-scale bias parameters that are\nin reasonable agreement wit
h observations. In this work we attempt to\ndevelop a deeper understanding
of the physical origin of the\nlarge-scale biasing of the forest. We have
run a series of\nhydrodynamic N-body simulations in order to compare nume
rically\nmeasured bias factors with analytical predictions from formulae\n
derived by Seljak (2012) using second-order perturbation theory. We\ndemon
strate the success of this theory in a fluctuating Gunn-Peterson\napproxim
ation (FGPA) framework for certain regimes\, and characterise\nits limitat
ions due to hydrodynamic effects\, such as thermal\nbroadening\, with the
hope of improving future theoretical\nmodels. Deeper understanding of the
large-scale Lyman-alpha biasing\nwill help us in using the large-scale clu
stering of the forest as a\ncosmological probe beyond baryon acoustic osci
llations.\n\nhttps://indico.cern.ch/event/438475/contributions/1090893/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090893/
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMB bispectrum
DTSTART;VALUE=DATE-TIME:20150908T145000Z
DTEND;VALUE=DATE-TIME:20150908T151000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090899@indico.cern.ch
DESCRIPTION:Speakers: Takashi Hiramatsu (Kyoto University\, Japan)\nCosmic
Microwave Background (CMB) is known as a remnant of Big-Bang\, and lots o
f past works in cosmology have paid attention to its potential to\nprove t
he very early Universe. In these days\, our main interests moved to quite
fine structures of the Universe\, for instance\, the statistical propertie
s of the\nprimordial fluctuations constructing the large-scale structure\,
and in fact we can investigate them thanks to rapid and sophisticated\nde
velopment of observational technologies. The simplest way to quantify the
non-trivial statistical properties of the fluctuations\nis to calculate th
eir bispectrum\, or three-point correlation function.\nIn our previous wor
k\, we developed a novel formalism\, curve-of-sight formula\, to compute t
he bispectrum of CMB temperature fluctuations\nin JCAP 10 (2014) 051\, and
have been developing a new Boltzmann solver implementing the curve-of-sig
ht formula.\nIn this talk\, we show the up-to-date numerical results of th
e CMB bispectrum using the curve-of-sight formula\, and also report\nthe c
urrent status of the development of our numerical code aiming at solving t
he 2nd-order Boltzmann equations.\n\nhttps://indico.cern.ch/event/438475/c
ontributions/1090899/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090899/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Measuring CMB Polarization with POLARBEAR and the Simons Array: To
wards New Constraints on Neutrino Masses and Inflation
DTSTART;VALUE=DATE-TIME:20150911T122000Z
DTEND;VALUE=DATE-TIME:20150911T124000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090866@indico.cern.ch
DESCRIPTION:Speakers: Christian Reichardt (University of Melbourne\, Austr
alia)\nMeasurements of the polarization of the cosmic microwave background
(CMB) are rapidly becoming an important tool to test the standard model o
f cosmology. In particular\, searches for the faint CMB B-mode signals off
er the prospect of detecting inflationary gravitational waves on large ang
ular scales and mapping out the large scale distribution of matter in the
Universe through CMB lensing on smaller angular scales. POLARBEAR is a CMB
polarization experiment located in the Atacama desert in Chile that has b
een pursuing both goals since 2012. The Simons Array is an expansion of th
e POLARBEAR experiment to three 3.5 meter telescopes with new multi-chroic
receivers. The first of these new receivers\, POLARBEAR-2\, will have fir
st light in 2016. With exceptional sensitivity in multiple frequency bands
and planned coverage of two thirds of the sky\, the Simons Array will yie
ld a high signal-to-noise mass map across most of the sky. Combining CMB l
ensing data from the Simons Array with future baryon acoustic oscillation
data results in a 1-sigma constraint on the sum of the neutrino masses of
19 meV when foregrounds are ignored\, increasing to 40 meV when including
component separation and foreground residuals. Even after foreground separ
ation\, the Simons Array will be able to measure tensor-to-scalar ratios (
r) as low as r = 0.014 at 2-sigma. We present the status of this funded in
strument and its expected capabilities.\n\nhttps://indico.cern.ch/event/43
8475/contributions/1090866/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090866/
END:VEVENT
BEGIN:VEVENT
SUMMARY:The decay of primordial magnetic fields and CMB spectral distortio
ns
DTSTART;VALUE=DATE-TIME:20150911T132000Z
DTEND;VALUE=DATE-TIME:20150911T134000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1091016@indico.cern.ch
DESCRIPTION:Speakers: Jacques Wagstaff (Hamburg University\, Germany)\nWe
calculate the CMB spectral distortions due to the decay of causally genera
ted magnetic fields at the electroweak and QCD phase transitions. We show
that the decay of non-helical magnetic fields generated at either the elec
troweak or QCD scale produce μ and y-type distortions below 10^−8 which
are probably not detectable by a future PIXIE-like experiment. We show th
at magnetic fields generated at the electroweak scale must have a helicity
fraction f∗>10^−4 in order to produce detectable μ-type distortions.
Hence a positive detection coming from the decay of magnetic fields would
rule out non-helical primordial magnetic fields and provide a lower bound
on the magnetic helicity.\n\nhttps://indico.cern.ch/event/438475/contribu
tions/1091016/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1091016/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Post-Newtonian Cosmological Modelling
DTSTART;VALUE=DATE-TIME:20150911T130000Z
DTEND;VALUE=DATE-TIME:20150911T132000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090870@indico.cern.ch
DESCRIPTION:Speakers: Viraj Sanghai (Queen Mary University of London\, Uni
ted Kingdom)\nWe construct a framework to probe the effect of non-linear s
tructure formation on the large-scale expansion of the universe. We take a
bottom-up approach to cosmological modelling by splitting up our universe
into cells. The matter content within each cell is described by the post-
Newtonian formalism. We assume that most of the cell is in the vicinity of
weak gravitational fields\, so that it can be described using a perturbed
Minkowski metric. Our cells are patched together using the Israel junctio
n conditions. We impose reflection symmetry across the boundary of these c
ells. This allows us to calculate the equation of motion for the boundary
of the cell and\, hence\, the expansion rate of the universe. At Newtonian
order\, we recover the standard Friedmann-like equations. At post-Newtoni
an orders\, we obtain a correction to the large-scale expansion of the uni
verse. Our framework does not depend on the ambiguous process of averaging
in cosmology.\n\nhttps://indico.cern.ch/event/438475/contributions/109087
0/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090870/
END:VEVENT
BEGIN:VEVENT
SUMMARY:The structure of the real line and cosmology
DTSTART;VALUE=DATE-TIME:20150911T124000Z
DTEND;VALUE=DATE-TIME:20150911T130000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090868@indico.cern.ch
DESCRIPTION:Speakers: Pawel Klimasara (University of Silesia\, Poland)\nWe
discuss the recently proposed model where LSS of spacetime is parametrize
d by the usual real line R\, while at small (QM) scales space is parametri
zed by real numbers from RM. Here RM is the real line in certain model M o
f formal Zermelo-Fraenkel set theory. When passing from RM to R the set-th
eoretic forcing on measure algebra of R3 has to be performed. The "old" se
t of reals RM is merely a meager subset of R. Moreover\, it has the Lebesg
ue measure 0. This irregular meager set of reals describes space at the Pl
anck era. From the point of view of the enlarged by forcing model M[G] wit
h the "new" reals RM[G]\, the set RM⊂RM[G] is irregular. We consider the
possible role of these irregularities in the scenario where primordial qu
antum fluctuations lead to the subsequent structure formation. The effects
of such irregularities on the eventual distortions in the CMB are also di
scussed.\n\nhttps://indico.cern.ch/event/438475/contributions/1090868/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090868/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cosmology on the Largest Scales
DTSTART;VALUE=DATE-TIME:20150910T120000Z
DTEND;VALUE=DATE-TIME:20150910T122000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090881@indico.cern.ch
DESCRIPTION:Speakers: Stefano Camera (Jodrell Bank Centre for Astrophysics
\, United Kingdom)\nUltra-large cosmic scales supply a wealth of informati
on most valuable for strengthening our knowledge of the Universe. For inst
ance\, they can teach us about the physical processes at play during the i
nflationary epoch\, or enable us to either further confirm or rule out Ein
stein's theory of general relativity. This is because: on the one hand\, t
here are relativistic corrections to the Newtonian prediction that only be
come important on extremely large scales\; and\, on the other hand\, those
scales may hide signatures of modifications to gravity. However\, the lar
gest cosmic scales have hitherto proven to be utterly difficult to access.
Here\, I show how it will be possible to access the ultra-large scale inf
ormation with the next generation of cosmological surveys such as Euclid o
r the Square Kilometre Array. I will also show that ultra-large scale effe
cts must be properly taken into account in the view of future cosmological
experiments\, if we do not want to bias our results.\n\nhttps://indico.ce
rn.ch/event/438475/contributions/1090881/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090881/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Robust forecasts on inflationary science from the foreground-obscu
red\, gravitationally lensed CMB polarisation
DTSTART;VALUE=DATE-TIME:20150910T132000Z
DTEND;VALUE=DATE-TIME:20150910T134000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090912@indico.cern.ch
DESCRIPTION:Speakers: Stephen Feeney (Imperial College London\, United Kin
gdom)\nRecent results from the BICEP2\, Keck Array and Planck collaboratio
ns demonstrate that Galactic foregrounds are an unavoidable obstacle in th
e search for evidence of inflationary gravitational waves in the cosmic mi
crowave background (CMB) polarisation. Beyond the foregrounds\, the effect
s of lensing by intervening large-scale structure further obscure all but
the strongest inflationary signals permitted by current data. With a pleth
ora of ongoing and upcoming experiments aiming to measure these signatures
\, careful and self-consistent consideration of experiments’ foreground-
and lensing-removal capabilities is critical in obtaining credible foreca
sts of their performance.\n\nI will present a Python-based Fisher framewor
k that performs just this task. Using data-driven foreground models with u
ser-defined components\, this tool first estimates the residuals and noise
in the CMB maps produced by maximum-likelihood component separation. It t
hen forecasts the ability of experiments to delens these maps\, via iterat
ive CMB-only techniques or cross-correlation with external data\, and then
ce constrain inflationary cosmology. Publicly available through an online
interface\, this tool allows the next generation of CMB telescopes to fore
ground-proof their designs\, optimise their frequency coverage to maximise
scientific output\, and determine where cross-experimental collaboration
would be most beneficial.\n\nhttps://indico.cern.ch/event/438475/contribut
ions/1090912/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090912/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Is there evidence for anisotropy in CMB data?
DTSTART;VALUE=DATE-TIME:20150909T082000Z
DTEND;VALUE=DATE-TIME:20150909T084000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1091013@indico.cern.ch
DESCRIPTION:Speakers: Daniela Saadeh (University College London\, United K
ingdom)\nLarge scales in the Cosmic Microwave Background (CMB) may break s
tatistical isotropy. Bianchi models are often invoked as a possible explan
ation for these low-\\ell features: they provide an anisotropic underlying
pattern over which the usual stochastic fluctuations are superimposed. Ho
wever\, the Bianchi models generally employed in the analysis of CMB data
— despite mimicking the anomalies in the CMB temperature map — overpro
duce B-mode polarisation due to the very specific way in which they break
isotropy.\nIn this work\, we consider a more physical class of Bianchi mod
els that satisfy polarisation constraints and test for their signatures in
Planck temperature and polarisation maps\; WMAP data are also analysed fo
r comparison. We take into account all the possible ways to break Friedman
n-Robertson-Walker isotropy\, whilst preserving homogeneity. We also test
for the well-known Bianchi models that are more commonly employed in the l
iterature\, and show that we are able to improve constraints on these mode
ls by extending the likelihood to high \\ell. Nested sampling techniques a
re employed to determine whether the Bayesian evidence favours anisotropic
universes over the standard Lambda-CDM scenario.\n\nhttps://indico.cern.c
h/event/438475/contributions/1091013/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1091013/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Constraining higher-order primordial non-Gaussianity from power sp
ectra and bispectra of imaging survey
DTSTART;VALUE=DATE-TIME:20150909T101000Z
DTEND;VALUE=DATE-TIME:20150909T103000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090858@indico.cern.ch
DESCRIPTION:Speakers: Ichihiko Hashimoto (Kyoto University\, Japan)\nDetec
tion of primordial non-Gaussianity (PNG) is recognized as a powerful probe
of cosmic inflation\, and it can give an important clue for the generatio
n mechanism of primordial density fluctuations. In this talk\, we specific
ally consider the local-type PNG and discuss how well one can tightly cons
train the higher-order non-Gaussianity parameters (gNL and tauNL) as well
as the leading order (fNL). While the recent CMB measurement by Planck put
s a tight constraint on fNL\, the constraints on gNL and tauNL are still w
eak. It is however known that the local-type PNG induces a strong scale-de
pendent behavior in the galaxy/halo clustering\, and this can provide a wa
y to put a more stringent constraint on PNG. Here\, we examine the statist
ical power of this effect by combining both power spectra and bispectra of
photometric/imaging galaxy surveys. Fisher matrix analysis reveals that t
he combination of power spectra and bispectra can break the degeneracy bet
ween non-Gaussianity parameters (fNL\,gNL and tauNL) and this will give si
multaneous constraints on those three parameters. As a result\, upcoming s
urveys like the Large Synoptic Survey Telescope have the potential to impr
ove the constraints on PNG much tighter than those obtained from the CMB m
easurements\, giving us an opportunity to test the single-field consistenc
y relation\, tauNL>=(36/25)fNL2.\n\nhttps://indico.cern.ch/event/438475/co
ntributions/1090858/
LOCATION: Rm 207
URL:https://indico.cern.ch/event/438475/contributions/1090858/
END:VEVENT
BEGIN:VEVENT
SUMMARY:General relativistic corrections in N-body simulations -- The N-bo
dy gauge
DTSTART;VALUE=DATE-TIME:20150909T091000Z
DTEND;VALUE=DATE-TIME:20150909T093000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090989@indico.cern.ch
DESCRIPTION:Speakers: Christian Fidler (CP3 \, Belgium)\nWe discuss differ
ent gauge choices and their advantages in the context of N-body simulation
s. The initial conditions for N-body simulations are usually generated by
employing the Zel'dovich approximation. We show that the initial displacem
ents generated in this way generally receive a first-order relativistic co
rrection.\nWe identify a novel gauge\, called N-body gauge in the followin
g\, in which this relativistic correction is absent. Therefore the Zel'dov
ich approximation provides accurate initial conditions in the N-body gauge
.\nFurthermore we show that a conventional Newtonian N-body simulation inc
ludes all first-order relativistic contributions in the absence of pressur
e perturbations and anisotropic stresses if we identify the coordinates in
Newtonian simulations with those in the N-body gauge.\nWe therefore concl
ude that the N-body gauge is uniquely suited for N-body simulations. When
setting the initial conditions using the Zel'dovich approximation and runn
ing a conventional Newtonian N-body simulation the results include all lin
ear relativistic effects if the output is understood in terms of the N-bod
y gauge. \nIn addition we analyse the limitations of the N-body gauge due
to pressure perturbations and anisotropic stresses from residual radiation
or a non standart cosmology.\n\nhttps://indico.cern.ch/event/438475/contr
ibutions/1090989/
LOCATION: Rm 207
URL:https://indico.cern.ch/event/438475/contributions/1090989/
END:VEVENT
BEGIN:VEVENT
SUMMARY:The SPIDER experiment: Instrument review\, flight performance\, an
d preliminary results
DTSTART;VALUE=DATE-TIME:20150908T141000Z
DTEND;VALUE=DATE-TIME:20150908T143000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090921@indico.cern.ch
DESCRIPTION:Speakers: Jon Gudmundsson (Stockholm University\, Sweden)\nSPI
DER is a balloon-borne experiment designed to image the polarization of th
e cosmic microwave background with the aim of constraining models of the e
arly universe. The experiment performed successfully during a 17 day fligh
t in the 2014-2015 Antarctic season. During this first flight\, SPIDER dep
loyed a total of 2000 detectors\, operating at 94 and 150 GHz\, to map app
roximately 10% of the sky in the Southern Galactic Hemisphere. The dataset
generated during this first flight should help provide the electromagneti
c\, spatial\, and angular constraints required to characterize the B-mode
signal properties. We will briefly review the instrument design\, discuss
flight performance\, and describe early analysis results. We will conclude
with plans for a subsequent flight of the SPIDER payload.\n\nhttps://indi
co.cern.ch/event/438475/contributions/1090921/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090921/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Measuring the speed of light with Baryon Acoustic Oscillations
DTSTART;VALUE=DATE-TIME:20150908T130000Z
DTEND;VALUE=DATE-TIME:20150908T132000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090963@indico.cern.ch
DESCRIPTION:Speakers: Vincenzo Salzano (University of Szczecin\, Poland)\n
We describe a new method to use Baryon Acoustic Oscillations to derive a c
onstraint on the possible variation of the speed of light. The method reli
es on the fact that there is a simple relation between the angular diamete
r distance maximum and the Hubble function evaluated at the same maximum-c
ondition redshift\, which includes speed of light c. We evaluate if curren
t or future missions can be sensitive enough to detect any variation of c.
\n\nhttps://indico.cern.ch/event/438475/contributions/1090963/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090963/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Oscillations in the CMB bispectrum
DTSTART;VALUE=DATE-TIME:20150908T143000Z
DTEND;VALUE=DATE-TIME:20150908T145000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090915@indico.cern.ch
DESCRIPTION:Speakers: Moritz Munchmeyer (Universite Pierre et Marie Curie\
, Institute Astrophysique de Paris\, France)\nOscillating signatures in th
e correlation functions of the primordial density perturbations are predic
ted by a variety of inflationary models. A theoretical mechanism that has
attracted much attention is a periodic shift symmetry as implemented in ax
ion monodromy inflation. This symmetry leads to resonance non-gaussianitie
s\, whose key feature are logarithmically stretched oscillations. Oscillat
ions are also a generic consequence of excited states during inflation and
of sharp features in the potential. Oscillating shapes are therefore a ve
ry interesting experimental target. \nAfter giving an overview of these mo
tivations\, I will discuss how to search for these signatures in the CMB.
Fast oscillations are difficult to search for with traditional estimation
techniques\, and I will demonstrate how targeted expansions\, that exploit
the symmetry properties of the shapes\, allow to circumvent these difficu
lties. As a member of the Planck collaboration\, I will discuss the Planck
results that have been obtained using these methods in the bispectrum\, a
s well as a joint search using bispectrum and power spectrum. Due to their
low overlap with other non-gaussian shapes\, oscillating bispectrum shape
s are not exhaustively constrained and a potential discovery is therefore
not yet ruled out.\nMy talk will be based in particular on arxiv:1412.3461
\, arxiv:1505.05882 and Planck publications on inflation and non-gaussiani
ties.\n\nhttps://indico.cern.ch/event/438475/contributions/1090915/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090915/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Primordial black holes as biased tracers
DTSTART;VALUE=DATE-TIME:20150910T155000Z
DTEND;VALUE=DATE-TIME:20150910T161000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090886@indico.cern.ch
DESCRIPTION:Speakers: Yuichiro Tada (Kavli IPMU\, Japan)\nPrimordial black
holes (PBHs) are theoretical black holes which can be formed during the r
adiation dominant era through the gravitational collapse of radiational ov
erdensities. It has been well known that in the context of the structure f
ormation in our Universe such collapsed objects\, e.g.\, halos/galaxies\,
could be considered as bias tracers of underlying matter fluctuations and
the halo/galaxy bias has been studied well. Applying such a biased tracer
picture to PBHs\, we investigate the large scale clustering of PBHs and ob
tain an almost mass-independent constraint to the scenario that the dark m
atter (DM) consists of PBHs. We focus on the case where the statistics of
the primordial curvature perturbations is almost Gaussian\, but with small
local-type non-Gaussianity. If PBHs account for the DM abundance\, such a
large scale clustering of PBHs behaves as nothing but the matter isocurva
ture perturbation which is strictly constrained by the observations of cos
mic microwave backgrounds (CMBs). From this constraint\, we show that\, in
the case where a certain single field causes both CMB temperature perturb
ations and PBH formation\, the PBH-DM scenario is excluded even with quite
small local-type non-Gaussianity\, |fNL| ∼ O(0.01).\n\nhttps://indico.c
ern.ch/event/438475/contributions/1090886/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090886/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Halo/Galaxy Bispectrum with Equilateral-type Primordial Trispectru
m
DTSTART;VALUE=DATE-TIME:20150910T141000Z
DTEND;VALUE=DATE-TIME:20150910T143000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090959@indico.cern.ch
DESCRIPTION:Speakers: Shuntaro Mizuno (Waseda University\, Japan)\nWe inve
stigate the effect of equilateral-type primordial trispectrum on the halo/
galaxy bispectrum.\nWe consider three types of equilateral primordial tris
pectra which are generated by quartic operators naturally appearing\nin th
e effective field theory of inflation and can be characterized by three no
nlinearity parameters\,\n$g_{\\rm NL} ^{\\dot{\\sigma}^4}$\, $g_{\\rm NL}
^{\\dot{\\sigma}^2 (\\partial \\sigma)^2}$\, and\n$g_{\\rm NL} ^{(\\partia
l \\sigma)^4}$.\nRecently\, constraints on these parameters have been inve
stigated from cosmic microwave background (CMB) observations by using WMAP
9 data.\nIn order to consider the halo/galaxy bispectrum with the equilate
ral-type primordial trispectra\,\nwe adopt the integrated perturbation the
ory (iPT) in which the effects of primordial\nnon-Gaussianity are wholly e
ncapsulated in the linear primordial polyspectrum for the evaluation of th
e biased polyspectrum.\nWe show the shapes of the halo/galaxy bispectrum w
ith the equilateral-type primordial trispectra\,\nand find that one type o
f the primordial trispectrum provides the same scale dependence as\nthe gr
avity-induced halo/galaxy bispectrum.\nOn the other hand\, the other two-t
ypes of \nprimordial trispectra characterized by \nprovide the common scal
e dependence which is different from that of the gravity-induced halo/gala
xy bispectrum\non large scales.\n\nhttps://indico.cern.ch/event/438475/con
tributions/1090959/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090959/
END:VEVENT
BEGIN:VEVENT
SUMMARY:An introduction to 21cm cosmology using HI intensity mapping
DTSTART;VALUE=DATE-TIME:20150910T130000Z
DTEND;VALUE=DATE-TIME:20150910T132000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090943@indico.cern.ch
DESCRIPTION:Speakers: Alkistis Pourtsidou (University of Portsmouth\, Unit
ed Kingdom)\n21cm cosmology is a new and exciting area of research with\na
great deal of potential. We have now entered an era of precision cosmolog
y\, but almost all of the information used to achieve this precision has c
ome from the CMB at redshift z ~ 1100 or from galaxy surveys below z ~ 1.5
. Using observations of the redshifted 21 cm line of atomic hydrogen (HI)
we can look at previously unexplored epochs\, like the Dark Ages and the E
poch of Reionization (EoR)\, as well as complement (and compete with) the
results from galaxy surveys at low redshifts. \n\nIn this talk I will pres
ent recent work on Weak Lensing studies using 21-cm radiation from the EoR
as well as from a post-reionization "intermediate" redshift range (2\n\nh
ttps://indico.cern.ch/event/438475/contributions/1090943/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090943/
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMB lensing and deflection angles in high precison cosmology
DTSTART;VALUE=DATE-TIME:20150909T080000Z
DTEND;VALUE=DATE-TIME:20150909T082000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090842@indico.cern.ch
DESCRIPTION:Speakers: Giuseppe Fanizza (Universita di Bari\, Italy)\nWe pr
esent a new method to compute the deflection of light rays in a perturbed
FLRW\ngeometry. By using the properties of the Geodesic Light Cone (GLC) g
auge where null rays\npropagate at constant angular coordinates irrespecti
vely of the given (inhomogeneous and/or\nanisotropic) geometry\, the gravi
tational deflection of null geodesics can then be obtained \nin any other
gauge. This connection can be done by expressing the angular coordinates o
f the given gauge in terms\nof the GLC angular coordinates. We apply this
method to the standard Poisson gauge\,\nincluding scalar perturbations\, a
nd give the full result for the deflection effect in terms of\nthe directi
on of observation and observed redshift up to second order\, and up to thi
rd order\nfor the leading lensing terms. Furthermore\, we also discuss the
connection with literature and estimate the effects of lensing on the CMB
temperature.\n\nhttps://indico.cern.ch/event/438475/contributions/1090842
/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090842/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dark energy and non-linear power spectrum
DTSTART;VALUE=DATE-TIME:20150910T143000Z
DTEND;VALUE=DATE-TIME:20150910T145000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090949@indico.cern.ch
DESCRIPTION:Speakers: Jinn-Ouk Gong (Asia Pacific Center for Theoretical P
hysics\, Republic of Korea)\nWe investigate the effects of homogeneous gen
eral dark energy on the non-linear matter perturbation in fully general re
lativistic context. The equation for the density contrast contains even at
linear order new contributions which are non-zero for general dark energy
. Taking into account the next-to-leading corrections\, the total power sp
ectrum with general dark energy deviates from the $\\Lambda$CDM spectrum\,
which is nearly identical to that in the Einstein-de Sitter universe\, as
large as a few percent at scales comparable to that for the baryon acoust
ic oscillations and increases on smaller scales. The contribution from the
curvature perturbation\, which is absent in the Newtonian theory\, exhibi
ts even more drastic difference larger than 100%\, while the amplitude is
heavily suppressed on all scales.\n\nhttps://indico.cern.ch/event/438475/c
ontributions/1090949/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090949/
END:VEVENT
BEGIN:VEVENT
SUMMARY:The effect of clustering dark energy on cosmological parameter est
imation
DTSTART;VALUE=DATE-TIME:20150908T155000Z
DTEND;VALUE=DATE-TIME:20150908T161000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090863@indico.cern.ch
DESCRIPTION:Speakers: Caroline Heneka (Dark Cosmology Centre\, Denmark)\nC
lustering dark energy presents interesting phenomonology in comparison to
standard homogeneous dark energy models. We investigate the impact of clus
tering dark energy on structure formation. Employing the spherical collaps
e formalism we obtain the collapse and virial density thresholds\, as well
as additional mass contributions due to non-linear dark energy perturbati
ons. For an accurate description\, the halo mass function is carefully rec
alibrated to include these non-linear effects of clustering dark energy. U
sing our MCMC likelihood analysis of X-ray cluster samples calibrated with
weak gravitational lensing data together with standard cosmological data
sets\, we constrain cosmological parameters when incorporating these non-l
inear corrections. We emphasise the impact on the constraints of the cosmo
logical parameters and the relevance of including these corrections in the
cluster mass function calculation.\n\nhttps://indico.cern.ch/event/438475
/contributions/1090863/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090863/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Using dark energy to suppress power at small scales
DTSTART;VALUE=DATE-TIME:20150909T095000Z
DTEND;VALUE=DATE-TIME:20150909T101000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090990@indico.cern.ch
DESCRIPTION:Speakers: Ignacy Sawicki (University of Geneva\, Switzerland)\
nThere remains a slight but chronic tension between the latest Planck resu
lts and low-redshift observables: power seems to be consistently lacking a
t late times. I will describe how a simple model of dark energy\, which ha
s the same expansion history as LCDM\, induces a scale-dependent correctio
n to the growth rate of dark matter\, suppressing power small scales. Sinc
e observations in the late universe are performed at smaller scales\, this
brings the early and late universe into better agreement. I will argue th
at such scale-dependent behaviour is completely generic in models of dynam
ical dark energy and modified gravity and must be properly accounted for i
n modelling of theories and observations.\n\nhttps://indico.cern.ch/event/
438475/contributions/1090990/
LOCATION: Rm 207
URL:https://indico.cern.ch/event/438475/contributions/1090990/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Evading non-linearities: Baryon Acoustic Oscillations at the linea
r point
DTSTART;VALUE=DATE-TIME:20150909T101000Z
DTEND;VALUE=DATE-TIME:20150909T103000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090924@indico.cern.ch
DESCRIPTION:Speakers: Stefano Anselmi (Case Western Reserve University\, U
nited States)\nCosmology has made fundamental progress thanks to the role
of standard rulers. The acoustic peak in the Large Scale Structure cluster
ing correlation function is one of them. However\, in the era of precision
cosmology\, its power has been highly challenged by how late time non-lin
earities distort the correlation function. Fortunately this is not the end
of the story! I will explain how we can evade non-linearities identifying
a scale in the correlation function\, called the “linear point”\, tha
t is an excellent cosmological standard ruler: its position is insensitive
to non-linear gravity\, redshift space distortions\, and scale-dependent
bias at the 0.5% level\; it is geometrical\, i.e. independent of the power
spectrum of the primordial density fluctuation parameters. Moreover\, the
linear point increases its appeal as it is easily identified irrespective
ly of how non-linearities distort the correlation function. Equally releva
nt\, the correlation function amplitude at the linear point is similarly i
nsensitive to non-linear corrections to within a few percent. Therefore\,
exploiting the particular Baryon features in the correlation function\, we
propose three new estimators for growth measurements. We perform a prelim
inary test in current data finding encouraging results and motivating more
careful future investigations.\n\nhttps://indico.cern.ch/event/438475/con
tributions/1090924/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090924/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Weak lensing signals induced from second-order vector perturbation
DTSTART;VALUE=DATE-TIME:20150909T093000Z
DTEND;VALUE=DATE-TIME:20150909T095000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090991@indico.cern.ch
DESCRIPTION:Speakers: Shohei Saga (Nagoya University\, Japan)\nThe standar
d cosmological perturbation theory is well established by by a number of o
bservations such as the CMB anisotropy or the Large scales structure.\nThe
standard cosmological perturbation theory includes three independent mode
s\, i.e.\, scalar\, vector\, and tensor modes.\nThe scalar mode is the do
minant component in our Universe and has been well determined by cosmologi
cal observations.\nConversely\, the vector mode is neglected in the standa
rd first-order cosmological perturbation theory since it only has a decayi
ng mode.\nThis situation changes if the cosmological perturbation theory i
s expanded up to second order.\nThe second-order vector and tensor modes a
re inevitably induced by the product of the first-order scalar modes.\nWe
study the effect of the second-order vector mode on the weak lensing curl-
and B-modes.\n\nhttps://indico.cern.ch/event/438475/contributions/1090991
/
LOCATION: Rm 207
URL:https://indico.cern.ch/event/438475/contributions/1090991/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Non-local bias in the halo bispectrum with primordial non-Gaussian
ity
DTSTART;VALUE=DATE-TIME:20150910T151000Z
DTEND;VALUE=DATE-TIME:20150910T153000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090891@indico.cern.ch
DESCRIPTION:Speakers: Matteo Tellarini (ICG\, Portsmouth\, United Kingdom)
\nPrimordial non-Gaussianity can lead to a scale-dependent bias in the den
sity of collapsed halos relative to the underlying matter density. The gal
axy power spectrum already provides constraints on local-type primordial n
on-Gaussianity complementary those from the cosmic microwave background (C
MB)\, while the bispectrum contains additional shape information and has t
he potential to outperform CMB constraints in future. We develop the bias
model for the halo density contrast in the presence of local-type primordi
al non-Gaussianity\, deriving a bivariate expansion up to second order in
terms of the local linear matter density contrast and the local gravitatio
nal potential in Lagrangian coordinates. Nonlinear evolution of the matter
density introduces a non-local tidal term in the halo model. Furthermore\
, the presence of local-type non-Gaussianity in the Lagrangian frame lead
s to a novel non-local convective term in the Eulerian frame\, that is pr
oportional to the displacement field when going beyond the spherical colla
pse approximation. We use an extended Press-Schechter approach to evaluate
the halo mass function and thus the halo bispectrum. We show that includi
ng these non-local terms in the halo bispectra can lead to corrections of
up to 25% for some configurations\, on large scales or at high redshift.\n
\nhttps://indico.cern.ch/event/438475/contributions/1090891/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090891/
END:VEVENT
BEGIN:VEVENT
SUMMARY:On Planck Asymmetries\, Alignments and Calibration.
DTSTART;VALUE=DATE-TIME:20150908T153000Z
DTEND;VALUE=DATE-TIME:20150908T155000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090986@indico.cern.ch
DESCRIPTION:Speakers: Alessio Notari (Universitat de Barcelona\, Spain)\nI
review several possible Anomalies for the Planck CMB data: the hemispheri
cal power asymmetry\, dipolar modulation and quadrupole-octupole alignment
s. I show that they are significantly affected by our proper motion. I als
o point out that the latter issue might be relevant also for the Calibrati
on of the HFI instrument itself.\n\nhttps://indico.cern.ch/event/438475/co
ntributions/1090986/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090986/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Decaying Dark Matter and the Discrepancy in sigma_8
DTSTART;VALUE=DATE-TIME:20150910T124000Z
DTEND;VALUE=DATE-TIME:20150910T130000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090946@indico.cern.ch
DESCRIPTION:Speakers: Toyokazu Sekiguchi (University of Helsinki\, Finland
)\nWe consider decaying dark matter (DDM) as a resolution to the possible
tension between cosmic microwave background (CMB) and weak lensing (WL) ba
sed determinations of the amplitude of matter fluctuations\, $\\sigma_8$.
We perform N-body simulations in a model where dark matter decays into dar
k radiation and develop an accurate fitting formula for the non-linear mat
ter power spectrum\, which enables us to test the DDM model by the combine
d measurements of CMB\, WL and the baryon acoustic oscillation (BAO). We e
mploy a Markov chain Monte Carlo analysis to examine the overlap of poster
ior distributions of the cosmological parameters\, comparing CMB alone wit
h WL+BAO. We find an overlap that is significantly larger in the DDM model
than in the standard CDM model. This may be hinting at DDM\, although cur
rent data is not constraining enough to unambiguously favour a non-zero da
rk matter decay rate $\\Gamma$. From the combined CMB+WL data\, we obtain
a lower bound $\\Gamma^{-1}>97$ Gyr at 95 % C.L\, which is less tight than
the constraint from CMB alone.\n\nhttps://indico.cern.ch/event/438475/con
tributions/1090946/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090946/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Anisotropic Correlations in Fourier Phases
DTSTART;VALUE=DATE-TIME:20150909T093000Z
DTEND;VALUE=DATE-TIME:20150909T095000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1091020@indico.cern.ch
DESCRIPTION:Speakers: Alexander Eggemeier (University of Sussex\, United K
ingdom)\nCorrelations in Fourier phases of the cosmological density field
arise as a consequence of non-linear structure formation. Since two-point
statistics are blind to phase factors\, measures of pure phase information
will not only be independent of the conventional power spectrum or two-po
int function\, they also do not suffer from Gaussian variance on the modul
us of the density field and linear bias. They may thus be regarded as an a
dditional and potentially valuable probe of large-scale structure in upcom
ing galaxy surveys. Starting from a recently proposed measure of phase inf
ormation\, the line correlation function\, I will present an anisotropic g
eneralisation that is capable of detecting anisotropies in the distributio
n of galaxies. Based on a number of numerical studies\, I will then discus
s how the Alcock-Paczynski effect and kinematical redshift-space distortio
ns can in principle be measured from Fourier phases.\n\nhttps://indico.cer
n.ch/event/438475/contributions/1091020/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1091020/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tension between the power spectrum of density perturbations measur
ed on large and small scales
DTSTART;VALUE=DATE-TIME:20150909T072000Z
DTEND;VALUE=DATE-TIME:20150909T074000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090869@indico.cern.ch
DESCRIPTION:Speakers: Tom Charnock (University of Nottingham\, United King
dom)\nThere is a tension between measurements of the amplitude of the powe
r spectrum of density perturbations inferred using the Cosmic Microwave Ba
ckground (CMB) and directly measured by Large-Scale Structure (LSS) on sma
ller scales. We show that this tension exists\, and is robust\, for a rang
e of LSS indicators including clusters\, lensing and redshift space distor
tions and using CMB data. One obvious way to try to reconcile this is the
inclusion of a massive neutrino which could be either active or sterile. U
sing Planck and a combination of LSS data we find that (i) for an active n
eutrino the sum of the neutrinos is m=(0.357+-0.99) eV and (ii) for a ster
ile neutrino m_sterile= (0.67+-0.18) eV and N_eff= 0.32+-0.20. This is\, h
owever\, at the expense of a degraded fit to Planck temperature data\, and
we quantify the residual tension at 2.5- and 1.6-sigma for massive and st
erile neutrinos respectively. We also consider alternative explanations in
cluding a lower redshift for reionization that would be in conflict with p
olarisation measurements made by WMAP and ad-hoc modications to primordial
power spectrum.\n\nhttps://indico.cern.ch/event/438475/contributions/1090
869/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090869/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Non-parametric Reconstruction of the Hubble Expansion History
DTSTART;VALUE=DATE-TIME:20150908T132000Z
DTEND;VALUE=DATE-TIME:20150908T134000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090922@indico.cern.ch
DESCRIPTION:Speakers: Hu Zhan (National Astronomical Observatories of Chin
a\, China)\nNon-parametric reconstruction is useful for constraining quant
ities that are potentially varying with time. A common practice is to repl
ace the continuous function with an interpolation over a set of points or
bins. This approach often involves many degrees of freedom\, so that the c
onstraints become too weak to be informative. In this presentation\, we di
scuss priors that can help reduce the uncertainties of reconstructed Hubbl
e parameters and dark energy equation of state. Specifically\, we propose
a physically motivated prior that requires the Hubble expansion rate to be
a non-decreasing function of redshift. Tests using SDSS-III and SNLS supe
rnova data show significant improvement with such a prior\, and the recons
tructed Hubble parameters are consistent with measurements from ages of pa
ssively evolving galaxies.\n\nhttps://indico.cern.ch/event/438475/contribu
tions/1090922/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090922/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Intrinsic galaxy size correlations and their importance for weak l
ensing
DTSTART;VALUE=DATE-TIME:20150909T074000Z
DTEND;VALUE=DATE-TIME:20150909T080000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090871@indico.cern.ch
DESCRIPTION:Speakers: Robert Crittenden (Institute of Cosmology and Gravit
ation\, United Kingdom)\nWe present a simple model for describing intrinsi
c correlations for galaxy sizes based on the halo model. Studying these co
rrelations is important both to improve our understanding of galaxy proper
ties and because it is an important potential systematic for weak lensing
size magnification measurements. Our model assumes that the density field
drives these intrinsic correlations and we also model the distribution of
satellite galaxies. We calculate the possible contamination to measurement
s of lensing convergence power spectrum from galaxy sizes\, and show that
the cross-correlation of intrinsic sizes with convergence is potentially a
n important systematic. We also explore how these intrinsic size correlati
ons may affect surveys with different redshift depth. We find that\, in th
is simple approach\, intrinsic size correlations cannot be neglected in or
der to estimate lensing convergence power spectrum for constraining cosmol
ogical parameters.\n\nhttps://indico.cern.ch/event/438475/contributions/10
90871/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090871/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Backreaction in Growing Neutrino Quintessence
DTSTART;VALUE=DATE-TIME:20150909T095000Z
DTEND;VALUE=DATE-TIME:20150909T101000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090988@indico.cern.ch
DESCRIPTION:Speakers: Florian Fuehrer (Institut fuer Theoretische Physik\,
Germany)\nIn Growing Neutrino Quintessence strong backreaction effects\,
induced from large neutrino non-linearities\, alter the cosmic history. I
will present results obtained from N-body simulations which includes relat
ivistic particles\, non-linear scalar field equations and backreaction eff
ects. Including the backreaction effects a realistic cosmology is hard to
realize. This points to the need of models with field dependent couplings.
In those models the neutrino perturbations are still large\, but the back
reaction effects are much smaller\, a realistic cosmology is possible.\n\n
https://indico.cern.ch/event/438475/contributions/1090988/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090988/
END:VEVENT
BEGIN:VEVENT
SUMMARY:How to model the effect of small-scale structures on light propaga
tion?
DTSTART;VALUE=DATE-TIME:20150909T103000Z
DTEND;VALUE=DATE-TIME:20150909T105000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090862@indico.cern.ch
DESCRIPTION:Speakers: Pierre Fleury (IAP\, France)\nIn standard cosmology\
, observations are interpreted as if light propagated through a universe w
hose inhomogeneities are modeled by perturbations with respect to the FLRW
spacetime. However\, the very narrow light beams associated with point-li
ke sources—such as supernovae—probe the Universe at extremely small sc
ales (~AU)\, up to which the perturbative approach should break down. In t
his talk\, I will present an alternative framework where the lensing due t
o small-scale structures is treated as a diffusion process.\n\nhttps://ind
ico.cern.ch/event/438475/contributions/1090862/
LOCATION: Rm 207
URL:https://indico.cern.ch/event/438475/contributions/1090862/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Intensity Mapping and One-Point Statistics
DTSTART;VALUE=DATE-TIME:20150908T124000Z
DTEND;VALUE=DATE-TIME:20150908T130000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090961@indico.cern.ch
DESCRIPTION:Speakers: Patrick Breysse (Johns Hopkins University\, United S
tates)\nIntensity mapping is a promising new technique for studying the la
rge-scale structure of the universe at redshifts inaccessible to tradition
al galaxy surveys. Intensity mapping studies typically focus on two-point
statistics of a map such as the power spectrum. However\, because these
maps are highly non-Gaussian\, there is a wealth of additional information
which can be obtained by studying the one-point statistics. We illustrat
e this using a simple model of an intensity mapping survey targeting CO at
redshift 3. Using a P(D) analysis\, we demonstrate how to calculate the
one-point PDF of a map from a galaxy luminosity function. We also study t
he effects of emission lines from foreground galaxies by considering a pop
ulation of HCN emitting galaxies at redshift 2\, and show that the one-poi
nt statistics can be used to recover information about the target CO popul
ation without resorting to cross-correlation studies. We then demonstrate
how this one-point analysis can be used to break degeneracies present in
the two-point statistics of an intensity map to obtain useful cosmological
information.\n\nhttps://indico.cern.ch/event/438475/contributions/1090961
/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090961/
END:VEVENT
BEGIN:VEVENT
SUMMARY:On soft limits of large-scale structure correlation functions
DTSTART;VALUE=DATE-TIME:20150908T122000Z
DTEND;VALUE=DATE-TIME:20150908T124000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090849@indico.cern.ch
DESCRIPTION:Speakers: Laura Sagunski (DESY\, Germany)\nWe study soft limit
s of correlation functions for the density and velocity fields in\nthe the
ory of structure formation. First\, we re-derive the (resummed) consistenc
y conditions\nat unequal times using the eikonal approximation. These are
solely based on symmetry\narguments and are therefore universal. Then\, we
explore the existence of equal-time relations\nin the soft limit which\,
on the other hand\, depend on the interplay between soft and hard\nmodes.
We scrutinize two approaches in the literature: the time-flow formalism\,
and a\nbackground method where the soft mode is absorbed into a locally cu
rved cosmology. The\nlatter has been recently used to set up (angular aver
aged) ‘equal-time consistency relations’.\nWe explicitly demonstrate t
hat the time-flow relations and ‘equal-time consistency conditions’\na
re only fulfilled at the linear level\, and fail at next-to-leading order
for an Einstein de-\nSitter universe. While applied to the velocities both
proposals break down beyond leading\norder\, we find that the ‘equal-ti
me consistency conditions’ quantitatively approximates the\nperturbative
results for the density contrast. Thus\, we generalize the background met
hod to\nproperly incorporate the effect of curvature in the density and ve
locity fluctuations on short\nscales\, and discuss the reasons behind this
discrepancy. We conclude with a few comments\non practical implementation
s and future directions.\n\nhttps://indico.cern.ch/event/438475/contributi
ons/1090849/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090849/
END:VEVENT
BEGIN:VEVENT
SUMMARY:A convergent perturbation theory for Newtonian cosmological struct
ure formation
DTSTART;VALUE=DATE-TIME:20150911T120000Z
DTEND;VALUE=DATE-TIME:20150911T122000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090865@indico.cern.ch
DESCRIPTION:Speakers: Cornelius Rampf (Portsmouth University\, United King
dom)\nAnalytical methods have been fairly successful to understand the New
tonian regime of cosmological structure formation. Such methods are usuall
y based on standard perturbation techniques which are however only approxi
mative tools\, and therefore might be not able to achieve the required acc
uracy to confront the theory with data from upcoming surveys. In this talk
we show that it is actually possible to solve exactly for the non-linear
fluid equations\, if we consider an alternative approach to conventional p
erturbation theory. Indeed\, in this talk it is shown that in a flat\, col
d dark matter (CDM) dominated Universe with positive cosmological constant
(Λ)\, particle trajectories are analytical in time (representable by a c
onvergent Taylor series) until at least a finite time after decoupling. Th
e time variable used for this statement is the cosmic scale factor\, i.e.\
, the "a-time"\, and not the cosmic time. For this\, a Lagrangian-coordina
tes formulation of the Euler-Poisson equations is employed. Temporal analy
ticity for ΛCDM is found to be a consequence of novel explicit all-order
recursion relations for the a-time Taylor coefficients of the Lagrangian d
isplacement field\, from which we derive the convergence of the a-time Tay
lor series.\n\nhttps://indico.cern.ch/event/438475/contributions/1090865/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090865/
END:VEVENT
BEGIN:VEVENT
SUMMARY:New approach to cosmological perturbation theory from an effective
action
DTSTART;VALUE=DATE-TIME:20150909T091000Z
DTEND;VALUE=DATE-TIME:20150909T093000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1091019@indico.cern.ch
DESCRIPTION:Speakers: Mikhail Ivanov (Ecole Polytechnique Federale de Laus
anne\, Switzerland)\nThe large scale structure of the Universe will become
the leading observational probe in cosmology in the near future. However\
, the proper analysis of structure formation at small scales requires non-
linear effects to be taken into account. Straightforward attempts to do so
within perturbation theory faced several problems such as the appearance
of non-physical infra-red (IR) enhancements from soft modes at each given
loop correction. These spurious IR - enhancements\, although cancelled out
upon summing over all loop corrections\, complicate tremendously the anal
ysis of physical IR - effects at higher loop order. \nIn my talk I will pr
opose a new method to account for the non-linear clustering of dark matter
. This method is based on the ideas of effective action\, path integral an
d RG flow. I will show that our approach is free of spurious IR - enhance
ments and makes possible to resumm the physical effects of long-wavelength
perturbations that are crucial for the BAO peaks. I will compare our IR -
resummation method to the other known techniques and test it against N-bo
dy data for the power-spectrum and the correlation function.\n\nhttps://in
dico.cern.ch/event/438475/contributions/1091019/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1091019/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cross-correlation between the CMB lensing potential measured by Pl
anck and high-redshift Herschel-ATLAS galaxies
DTSTART;VALUE=DATE-TIME:20150910T145000Z
DTEND;VALUE=DATE-TIME:20150910T151000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090962@indico.cern.ch
DESCRIPTION:Speakers: Pawel Bielewicz (SISSA\, Italy)\nWe present the firs
t measurement of the correlation between the map of the CMB lensing potent
ial derived from the Planck mission data and high-redshift galaxies detect
ed by the Herschel-ATLAS (H-ATLAS) survey. This galaxy catalogue is the hi
ghest redshift sample for which the correlation between Planck CMB lensing
and tracers of large-scale structure has been investigated so far. We per
form a number of null tests and reject the no CMB lensing-galaxy correlati
on hypothesis at a 20σ significance. The significance of the detection of
the theoretically expected cross-correlation signal is found to be 10σ.
The estimated galaxy bias\, b=2.8 ± 0.1\, is consistent with earlier esti
mates of the bias for the H-ATLAS galaxies at similar redshift. On the oth
er hand\, the amplitude of the cross-correlation is found to be a factor 1
.6 ± 0.2 higher than expected from the standard model and found by cross-
correlation analyses with other tracers of the large-scale structure. We h
ave investigated few possible reasons for the excess amplitude however any
of them can not fully account for the enhanced cross-correlation signal.\
n\nhttps://indico.cern.ch/event/438475/contributions/1090962/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090962/
END:VEVENT
BEGIN:VEVENT
SUMMARY:CMB Lensing and Scale Dependent New Physics
DTSTART;VALUE=DATE-TIME:20150908T120000Z
DTEND;VALUE=DATE-TIME:20150908T122000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090925@indico.cern.ch
DESCRIPTION:Speakers: Eric Linder (UC Berkeley\, United States)\nCosmic mi
crowave background lensing has become a new cosmological probe\, carrying
rich information on the matter power spectrum and distances over the redsh
ift range z≈1-4. We investigate the role of scale dependent new physics\
, such as from modified gravity\, neutrino mass\, and cold (low sound spee
d) dark energy\, and its signature on CMB lensing. The distinction between
different scale dependences\, and the different redshift dependent weight
ing of the matter power spectrum entering into CMB lensing and other power
spectra\, imply that CMB lensing can probe simultaneously a diverse range
of physics. We highlight the role of arcminute resolution polarization ex
periments for distinguishing between physical effects.\n\nhttps://indico.c
ern.ch/event/438475/contributions/1090925/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090925/
END:VEVENT
BEGIN:VEVENT
SUMMARY:The Abundance of Extreme Cosmic Voids
DTSTART;VALUE=DATE-TIME:20150909T070000Z
DTEND;VALUE=DATE-TIME:20150909T072000Z
DTSTAMP;VALUE=DATE-TIME:20190620T142224Z
UID:indico-contribution-96956-1090867@indico.cern.ch
DESCRIPTION:Speakers: Siri Chongchitnan (University of Hull\, United Kingd
om)\nCosmic voids have been shown to be an effective probe of cosmology\,
complementary to galaxy clusters. But how reliable are the current theoret
ical models for void abundance?\nIn this talk\, I will explain how the the
ory of "extreme cosmic voids" can be used as a consistency test for theor
ies of void abundance. I will give a simple derivation of the size of the
largest voids expected within a given redshift and volume. This extreme-vo
id model is based on the exact extreme-value statistics which has previous
ly been successfully applied to massive galaxy clusters. \nI will show tha
t\, when compared with simulations and observations (e.g. SDSS voids)\, th
e Sheth and Van de Weygaert model (and simple adjustments thereof) general
ly yields a poor fit to the extreme-void abundance even though it appears
to give a good fit to the void distribution over some radius range. I will
discuss some insights into possible resolutions. \nBased on 1502.07705 (J
CAP in press).\n\nhttps://indico.cern.ch/event/438475/contributions/109086
7/
LOCATION: Main Hall
URL:https://indico.cern.ch/event/438475/contributions/1090867/
END:VEVENT
END:VCALENDAR