BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Extrema counts of 3D density fields as a new test of primordial no
 n-Gaussianity - Matteo Biagetti
DTSTART:20181105T130000Z
DTEND:20181105T140000Z
UID:TALK109456@talks.cam.ac.uk
CONTACT:Tobias Baldauf
DESCRIPTION:One of the main targets in cosmology is the understanding of t
 he primordial Universe and the mechanism that seeded the cosmic structures
  we observe today.\nDespite the great achievements of observing adiabatic\
 , nearly scale-invariant and very close to Gaussian  perturbations as pred
 icted by the simplest models of inflation\, we are still blind to the part
 icle content of inflation and the precise mechanism of production of primo
 rdial perturbations.\nObserving primordial non-Gaussianity is the best way
  to discriminate among models of inflation. Well-defined targets for the a
 mplitude of primordial non-Gaussianity are provided by theoretical argumen
 ts: for instance\, an order one PNG for squeezed triangles would rule out 
 single-field models of inflation.  \nUpcoming galaxy surveys in the next 5
 -10 years might have the sensitivity to reach this target. Here we propose
  a new method to observe PNG: a simple proof-of-principle analysis of the 
 extrema (minima and maxima) abundance of the smoothed dark matter and halo
  density fields in n-body simulations revealed that they are very sensitiv
 e to the presence to local-type PNG\, as expected from theoretical argumen
 ts. The strength of this method resides in the fact that the analysis is v
 ery simple to perform\, i.e. counting extrema in a smoothed density field\
 , as compared to the usual method of computing correlations of number coun
 ts. Despite not providing the required O(1) sensitivity on fNL for this pr
 eliminary analysis\, we show how this method can be improved in several di
 rections and also extended to other cosmological parameters\, such as for 
 example the abundance of dark matter in the Universe.
LOCATION:CMS\, Pav. B\, CTC Common Room (B1.19) [Potter Room]
END:VEVENT
END:VCALENDAR