The Next-Band All Sky Survey (NextBASS)

NextBASS and ProtoNextBASS are future experiments that will image the whole sky continuously in frequency from 6 GHz to 20 GHz, measuring both the brightness and the polarisation of the sky.


ProtoNextBASS is the prototype for NextBASS, making use of the retired ClOVER dishes and will provide invaluable testing of wideband receiver architectures. ProtoNextBASS will operate with two channels separated into a 6-12 GHz feed and a 12-20 GHz feed at a sensitivity of ~10µKdeg.

NextBASS will consist of three channels using multiple feeds to achieve a sensitivity that parallels that of higher frequency experiments such as Planck.

Science Goals

Following the success of CBASS, the Experimental Cosmology Group is designing an experiment to study foregrounds further in all bands above C-Band and below 40 GHz where the atmosphere starts to absorb radio waves. Sensitivity modelling demonstrates that low frequency contributions to observations are essential to constrain cosmological parameters.

Dotted lines are without Litebird, solid lines are with. Red: Planck. Blue: Planck + CBASS. Green: Planck + CBASS + ProtoNextBASS (low). Yellow: Planck + CBASS + ProtoNextBASS (low + high). Purple: Planck + CBASS + ProtoNextBASS (low + high) + NextBASS.

MCMC models using the estimated sensitivities of ProtoNextBASS and NextBASS demonstrate the improvement on cosmological constraints by introducing low frequency data to current CMB models. Low frequency ground based all sky surveys will help future B-mode satellite missions such as Litebird identify B-mode signals from primordial gravitational waves.

For more information contact Jaz Hill-Valler.