Polarized Galactic Emission Models at Small Scales (P-GEMSS)

Research Project, 2024 – 2027

The structure that we see looking far into the Universe was determined billions of years ago. Just moments after the Big Bang, the Universe entered a brief period of rapid expansion known as inflation. Tiny irregularities in the temperature of the Universe then grew dramatically, setting the stage for the first structures to form. This mysterious period is very difficult to study, because no light can reach us from that time. However, there may be an indirect way of ‘seeing’ the Universe during inflation. Gravitational waves left a pattern in the afterglow of the Big Bang. The afterglow became visible when the Universe was about 400,000 years old and is still visible now, as microwaves shining across the sky – the Cosmic Microwave Background (CMB).The pattern imprinted by gravitational waves on the CMB is extremely faint. So faint that our Galaxy’s microwave light outshines it completely. The Galaxy’s light also has patterns, encoded in a property of the light called polarization. These patterns can be mistaken for the inflationary signal. But, if we measure the Galactic light’s patterns carefully, we can learn how they are different from the pattern we expect from inflation. And this would allow us to disentangle them.‘Polarized Galactic Emission Models at Small Scales’ aims to measure the characteristic patterns in the polarization of Galactic light. It will create precise images of these patterns at high resolution, which can be used to unveil the pattern from inflation.