B-mode Detection with an Extended Planck Mission

TL;DR

An extended Planck mission with four sky surveys can significantly improve constraints on primordial B-mode polarization, enabling detection of low tensor-scalar ratios and better foreground control compared to the nominal mission.

Contribution

This study demonstrates the enhanced capability of an extended Planck mission to detect primordial B-modes and constrain tensor-scalar ratios, surpassing the nominal mission's limitations.

Findings

Detects r=0.05 at high significance

Sets 95% upper limit of r=0.03 if no signal

Improves foreground removal using additional frequency channels

Abstract

The Planck satellite has a nominal mission lifetime of 14 months allowing two complete surveys of the sky. Here we investigate the potential of an extended Planck mission of four sky surveys to constrain primordial B-mode anisotropies in the presence of dominant Galactic polarized foreground emission. An extended Planck mission is capable of powerful constraints on primordial B-modes at low multipoles, which cannot be probed by ground based or sub-orbital experiments. A tensor-scalar ratio of r=0.05 can be detected at a high significance level by an extended Planck mission and it should be possible to set a 95% upper limit on r of 0.03 if the tensor-scalar ratio is vanishingly small. Furthermore, extending the Planck mission to four sky surveys offers better control of polarized Galactic dust emission, since the 217 GHz frequency band can be used as an effective dust template in addition to the 353 GHz channel.