Special seminar with Dicke fellowship candidate: Cheng Zang, Caltech University
The inflationary theory has been added into the picture of the well-established lambda cold dark matter (ΛCDM) standard model to explain the initial conditions of our universe. The quantum fluctuations in the early universe were stretched into cosmic scale during the inflation and left signs in the Cosmic Microwave Background (CMB). The successful measurement of the CMB temperature power spectrum induced by scalar fluctuations marks the high point of modern cosmology. The tensor fluctuations, or the primordial gravitational waves, could leave a unique B-mode pattern in CMB polarization. The detection of the primordial B modes will be strong supporting evidence of inflation and give us opportunities to study physics at energy scales far beyond what can ever be accessed in laboratory experiments. As a graduate student, I have been working in the BICEP/Keck (BK) collaboration building B-mode telescopes for the past 6 years. In this talk, I will discuss the major challenge our B-mode experiment is facing – the polarized galactic foregrounds. I’ll talk about the development and deployment of the first BICEP Array receiver at 30/40 GHz, which will improve our constraints on the synchrotron foreground in the BK sky patch. I’ll conclude with the preliminary results from the receiver’s 1st-year data.