A Projected Estimate of the Reionization Optical Depth Using the CLASS Experiment’s Sample Variance Limited E-mode Measurement
Abstract
We analyze simulated maps of the Cosmology Large Angular Scale Surveyor (CLASS) experiment and recover a nearly cosmic variance limited estimate of the reionization optical depth τ. We use a power spectrum-based likelihood to simultaneously clean foregrounds and estimate cosmological parameters in multipole space. Using software specifically designed to constrain τ, the amplitude of scalar fluctuations A s , and the tensor-to-scalar ratio r, we demonstrate that the CLASS experiment will be able to estimate τ within a factor of two of the cosmic variance limit allowed by full-sky cosmic microwave background polarization measurements. Additionally, we discuss the role of CLASS’s τ constraint in conjunction with gravitational lensing of the CMB on obtaining a ≳4σ measurement of the sum of the neutrino masses.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- August 2018
- DOI:
- 10.3847/1538-4357/aad283
- arXiv:
- arXiv:1801.01481
- Bibcode:
- 2018ApJ...863..121W
- Keywords:
-
- cosmic background radiation;
- cosmological parameters;
- early universe;
- gravitational waves;
- inflation;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- Accepted for publication by ApJ