Cosmic Optical Background: the View from Pioneer 10/11

Understand

We present the new constraints on the cosmic optical background (COB) obtained from an analysis of the Pioneer 10/11 Imaging Photopolarimeter (IPP) data.

• After careful examination of data quality, the usable measurements free from the zodiacal light are integrated into sky maps at the blue (~0.44 um) and red (~0.64 um) bands.
• Accurate starlight subtraction is achieved by referring to all-sky star catalogs and a Galactic stellar population synthesis model down to 32.0 mag.
• We find that the residual light is separated into two components: one component shows a clear correlation with thermal 100 um brightness, while another betrays a constant level in the lowest 100 um brightness region.