Download presentation

Presentation is loading. Please wait.

Published byTaliyah Saddler Modified over 3 years ago

1
CMB temperature bispectrum from a cosmic string network Keitaro Takahashi (Kumamoto U) Based on the collaboration with Yamauchi (U Tokyo), Sendouda (Hirosaki U), Yoo (Nagoya), Hiramatsu (Kyoto)

2
Line-like topological defects Formed in the early universe through the spontaneous symmetry breaking F-strings, D-strings, and their bound states which appear in string theory Formed though the brane collision at the end of the stringy inflation Cosmic strings Cosmic superstrings P=1P~10 -3 <<1 Intercommuting probability P

3
String gravity : conical structure The spacetime around a straight cosmic string is locally flat. An angular wedge of width Δ=8πGμ is removed from the space and the remaining edges identified.

4
String-induced integrated Sachs-Wolfe effect [Planck 25 (2013)] (δT/T)/Gμ Cosmic strings create line-like discontinuities in the CMB signal. Gott-Kaiser-Stebbins (GKS) effect [Kaiser+Stebbins(1984), Gott III(1985)]

5
CMB temp. power spectrum induced by a cosmic string network An analytic model including the probabilistic nature of the intercomuting process [Yamauchi, KT, et al. (2011)] [Atacama Cosmology Telescope (ACT), 2010] For ACT, For Planck satellite,

6
geodesic potential CMB lensing Deflection of CMB photons Unlensed CMB map [Hu+Okamoto(2002)] z=z CMB z=z L z=0 Lensed CMB map Lensing contribution

7
“αβ-type” lensing bispectrum The anisotropy is assumed to be decomposed into (α,β : contributions from each components) “αβ-type” “αβ-type” lensing bispectrum

8
Various types of CMB lensing : contributions from cosmic strings SP-type PP-type (standard) PS-type SS-type Standard density pert. Cosmic strings Standard density pert. “P” : primordial density perturbations, “S” : string contributions

9
Equilateral-shaped bispectra induced by a cosmic string network Silk damping At small scale, the standard ISW-L (PP-type) and SP-type bispectra are damped due to the Silk damping, and only the (GKS) 3, PS-type bispectra are relevant. (Gμ,P) (10 -7,1) (10 -8,10 -3 ) (10 -9,10 -6 ) [Yamauchi, KT, et al., in prep.] SS-type ∝ C l Θsφs C l ΘsΘs ∝ (Gμ) 4 (GKS) 3 ∝ (Gμ) 3 Preliminary SP-type ∝ C l Θsφs C l ΘpΘp ∝ (Gμ) 2 PS-type ∝ C l Θpφp C l ΘsΘs ∝ (Gμ) 2

10
Cumulative signal-to-noise ratio (GKS) 3 ∝ (Gμ) 3 SS-type ∝ (Gμ) 4 PS-type ∝ (Gμ) 2 SP-type ∝ (Gμ) 2 PA : Planck+ACTPol–like noise, P : Planck-like noise [Yamauchi, KT, et al., in prep.] Preliminary

11
Constraint in Gμ-P plane ((S/N) <5000 =1) For small P, the PS-type GKS-L bispectrum ∝ C l Θpφp C l ΘsΘs ∝ (Gμ) 2 gives the tighter constraint on Gμ than the (GKS) 3 bispectrum ∝ (Gμ) 3. (GKS) 3 PS-type ∝ C l Θpφp C l ΘsΘs SP-type ∝ C l Θsφs C l ΘpΘp [Yamauchi, KT, et al., in prep.] Preliminary SS-type ∝ C l Θsφs C l ΘsΘs

12
Summary We study the effect of weak lensing by cosmic strings on the anisotropies of cosmic microwave background. In developing a method to evaluate the lensing contribution due to strings, we calculate the analytic expression for the various-type, namely αβ-type, lensing bispectra. For smaller tension, the lensing bispectrum have window to constrain the string parameters even tighter than the bispectrum induced by GKS.

Similar presentations

OK

Quantum Gravity: Infinities, Loops, and Strings Vsevolod Ivanov2014 What is THE question (and why do we care)? A quantum history The trouble with gravity.

Quantum Gravity: Infinities, Loops, and Strings Vsevolod Ivanov2014 What is THE question (and why do we care)? A quantum history The trouble with gravity.

© 2018 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on producers consumers and decomposers in the desert Ppt on solid dielectrics capacitors Ppt on central administrative tribunal orders Training ppt on quality Ppt on peak load pricing graph Biology ppt on reproduction Ppt on operations with complex numbers A ppt on water pollution Ppt on grease lubrication in rolling Ppt on the road not taken analysis