Speaker
Description
Titulo: The status of QUIJOTE telescopes: scientific results from the MFI, commissioning and cosmological forecasts for the TFGI
One of the main goals of current Cosmic Microwave Background (CMB) experiments is the detection of primordial B-modes, generated by gravitational waves during inflation. Achieving such a detection requires observations with exquisite polarization sensitivity, well beyond the capabilities of Planck. One promising approach is the use of a “true polarimeter” design, which produces polarization measurements for each individual detector and mitigates systematic effects, particularly bandpass leakage. This is the strategy adopted by the first two instruments installed in the QUIJOTE experiment.
The QUIJOTE experiment consists of two identical telescopes with 2.25-m diameter located in Tenerife, Spain. The first two instruments installed were the Multi Frequency Instrument, or MFI, which observed at four bands between 10 and 20 GHz, and the Thity-and-Forty Gigahertz Instrument, or TFGI, which observes at 30 and 40 GHz. While the former is focused on studying the low frequency foregrounds of the Cosmic Microwave Background (CMB), the latter will observe Northern sky regions with minimal contamination from foregrounds in order to provide deep and 1 $\mu$K deg$^{-1}$ sensitive maps.
In this talk, I will briefly mention the scientific results from MFI published by the QUIJOTE collaboration since 2023. I will give special emphasis to the Wide Survey, a public map of the sky north of $\delta=32^\circ$ at 11, 13, 17 and 19 GHz which consists of a total 9000 hours of observation covering 29000 deg$^2$. I will then move to present the results from the commissioning phase of the TFGI, conducted between November 2021 and October 2022. During this phase, the instrument observed with only 7 pixels out of the 29 total ones that can be fitted in its focal plane. Overall, the properties from theses pixels are consistent with expectations. Finally, I will show the sensitivity estimates for the TFGI, computed on noise half-maps built from observations of bright Galactic regions.
From these maps, we infer a polarization sensitivity of 8.4 $\mu$K deg$^{-1}$ after $0.57$ h deg$^{-2}$ of integration, using only two of the pixels. This is already comparable to the sensitivity reached by WMAP over its full mission. We show that, once all 29 TFGI pixels are operational, the instrument will achieve a sensitivity of $\sim1$ $\mu$K deg$^{-1}$ at both 31 and 41 GHz over three cosmological fields covering $3600$ deg$^2$ after 5.9 years of continuous observations. This sensitivity is sufficient to constrain the tensor-to-scalar ratio to $r \leq 0.05$, thereby meeting the TFGI design requirements.