Foreground Separation and Constraints on Primordial Gravitational Waves with the PICO Space Mission

PICO is a concept for a NASA probe-scale mission aiming to detect or constrain the tensor to scalar ratio \(r\), a parameter that quantifies the amplitude of inflationary gravity waves. We carry out map-based component separation on simulations with five foreground models and input \(r\) values \(r_{in}=0\) and \(r_{in} = 0.003\). We forecast \(r\) determinations using a Gaussian likelihood assuming either no delensing or a residual lensing factor \(A_{\rm lens}\) = 27%. By implementing the first full-sky, post component-separation, map-domain delensing, we show that PICO should be able to achieve \(A_{\rm lens}\) = 22% - 24%. For four of the five foreground models we find that PICO would be able to set the constraints \(r < 1.3 \times 10^{-4} \,\, \mbox{to} \,\, r