PhD Thesis Defense: Ti-Lin Chou

3:00–4:00 pm ERC 401

Ti-Lin Chou "IMPROVED MEASUREMENTS OF THE TEMPERATURE AND E-MODE POLARIZATION OF THE CMB FROM THE FULL 500-SQUARE-DEGREE SPTPOL DATASET"

We present updated measurements of the temperature and E-mode polarization maps of the cosmic microwave background (CMB), as well as the E-mode polarization auto-power spectrum (EE) and temperature-E-mode cross-power spectrum (TE) in the angular multipole range 50<ℓ<8000, using the full four-year SPTpol 500 deg² dataset in both the 95 GHz and 150 GHz frequency bands. These are the most sensitive measurements of the CMB damping tail to date above roughly ℓ>1700 in TE and ℓ>2000 in EE. This dataset and most of its subsets are good fits to the ΛCDM model. This dataset is self-consistent but has a curiosity that persists from the previously published SPTpol TE/EE analysis. The ΛCDM parameter constraints between the ℓ<1000 and ℓ>1000 data splits are different by ≲2σ, where ℓ<1000 prefers a low H₀ and a high 10⁹Aₛexp(-2��), and ℓ>1000 prefers a high H₀ and a low 10⁹Aₛexp(-2��). In 150 GHz, H₀ is 66.93±4.64 km s⁻¹ Mpc⁻¹ in the ℓ<1000 data split, and 74.98±3.73 km s⁻¹ Mpc⁻¹ in the ℓ>1000 data split. This same trend is seen in both 95 GHz data alone and 150 GHz data alone, which confirms this is a real feature on this 500 deg² patch of sky. We also find that the scaling of the lensing spectrum, inferred from the smearing of TE/EE power spectrum peaks, to be lower than unity (A_L = 0.70±0.13). When marginalized over A_L, our ΛCDM parameter constraints are consistent with those in Planck.

Committee Members: Thomas Crawford (Chair), John Carlstrom, Michael Turner, Cheng Chin

Event Type

PhD Thesis Defenses

Feb 9