Difference between revisions of "Forecastfiso planck"

From CMB-S4 wiki
Jump to navigationJump to search
(Created page with "== Overview == We can improve constraints on isocurvature perturbations from Planck with observations from S4. Here we consider the curvaton model: there is one isocurvature mod...")
 
Line 13: Line 13:
 
To check that we are getting reasonable results, we run the Fisher matrix with LCDM+Mnu+f_iso with Planck noise levels, beams, and fsky as specified in previous forecast checks.  
 
To check that we are getting reasonable results, we run the Fisher matrix with LCDM+Mnu+f_iso with Planck noise levels, beams, and fsky as specified in previous forecast checks.  
  
We tested for two fiducial cosmologies: (1) f_iso=0; (2) f_iso=0.01. The following constraints use TT/EE/TE lensed spectra.
+
We tested for fiducial cosmology f_iso=0 with CDM isocurvature modes; The following constraints use TT/EE/TE lensed spectra.
  
 
The following are the constraints we get:
 
The following are the constraints we get:
Line 19: Line 19:
 
|   
 
|   
 
| LCDM+Mnu+f_iso=0  
 
| LCDM+Mnu+f_iso=0  
| LCDM+Mnu+f_iso=0.01
 
 
|-  
 
|-  
 
|och2
 
|och2
 
| 0.001523
 
| 0.001523
| 0.001503
 
 
|-
 
|-
 
|obh2
 
|obh2
 
| 0.000163
 
| 0.000163
| 0.000160
 
 
|-
 
|-
 
|onuh2
 
|onuh2
 
| 0.005396
 
| 0.005396
| 0.005281
 
 
|-
 
|-
 
|10^9 As
 
|10^9 As
 
| 0.2589
 
| 0.2589
| 0.2529
 
 
|-
 
|-
 
|ns
 
|ns
 
| 0.00486
 
| 0.00486
| 0.00483
 
 
|-
 
|-
 
|tau
 
|tau
 
| 0.0597
 
| 0.0597
| 0.0584
 
 
|-
 
|-
 
|hubble
 
|hubble
 
| 4.84
 
| 4.84
| 4.73
 
 
|-
 
|-
 
|f_iso
 
|f_iso
 
| 0.00391
 
| 0.00391
| 0.00430
 
 
|}
 
|}
  
 
We are doing a literature search to find previous forecasts that uses a similar parameterization (as opposed to the alpha or beta parameterization) to compare our results.
 
We are doing a literature search to find previous forecasts that uses a similar parameterization (as opposed to the alpha or beta parameterization) to compare our results.

Revision as of 08:31, 27 May 2016

Overview

We can improve constraints on isocurvature perturbations from Planck with observations from S4.

Here we consider the curvaton model: there is one isocurvature mode: the CDM isocurvature, and the spectral index of the CDM mode is the same as that of the adiabatic scalar perturbations, n_s. In this scenario, the CDM mode is either totally correlated or anti-correlated with the adiabatic perturbations.

The parameter we are constraining is f_iso, the primordial fraction of CDM isocurvature amplitude to the scalar perturbation amplitude. Specifically, the final spectra is

Cl^{tot} = Cl^{ad} + f_iso^2 Cl^{cdm iso} + 2* f_iso * Cl^{correlated}

where Cl^{cdm iso} is generated such that it has the same primordial power A_s as the scalar perturbations, and similarly for Cl^{correlated}.

Planck test

To check that we are getting reasonable results, we run the Fisher matrix with LCDM+Mnu+f_iso with Planck noise levels, beams, and fsky as specified in previous forecast checks.

We tested for fiducial cosmology f_iso=0 with CDM isocurvature modes; The following constraints use TT/EE/TE lensed spectra.

The following are the constraints we get:

LCDM+Mnu+f_iso=0
och2 0.001523
obh2 0.000163
onuh2 0.005396
10^9 As 0.2589
ns 0.00486
tau 0.0597
hubble 4.84
f_iso 0.00391

We are doing a literature search to find previous forecasts that uses a similar parameterization (as opposed to the alpha or beta parameterization) to compare our results.