Gravity Group Seminar | Xue (Sherry) Song, Joseph van der List, and Corwin Shiu, PU "B-mode Constraint from SPIDER's First Flight"

SPIDER is a balloon-borne telescope designed to map the B-mode polarization of the cosmic microwave background (CMB) on degree angular scales. SPIDER’s 2015 flight mapped 4.8% of the sky at 95 and 150 GHz. In this talk, we report the results of internal consistency tests performed on the data to control against instrumental systematics, and discuss the two independent foreground-removal techniques employed to account for Galactic emission. The primary foreground subtraction method uses a dust template derived from Planck data. The second approach is a joint analysis of SPIDER and Planck data in the harmonic domain. We derive 95% upper limits on the primordial tensor-to-scalar ratio, finding r < 0.11 (Feldman–Cousins) and r < 0.19 (Bayesian).