Title:	Antenna Design for Absolute Sky Measurements at Gigahertz Frequencies—a First Step toward Detecting CMB Spectral Distortions from Recombination
Authors:	Sathish, Keerthipriya Rao, Mayuri Sathyanarayana Sarkar, Debdeep
Keywords:	Radio receivers Radio astronomy Radio telescopes Ground telescopes Ground-based astronomy Cosmology Recombination (cosmology) Reionization
Issue Date:	28-Jun-2024
Publisher:	IOP Publishing Ltd.
Citation:	The Astrophysical Journal, 2024, Vol. 168, p39
Abstract:	There exist inevitable deviations in the cosmic microwave background spectrum from that of a blackbody. The additive distortions from photons emitted over the epoch of recombination are one such deviation. We present a novel scalable broadband antenna design motivated by detecting these spectral distortions in the 2.5–4 GHz band. This antenna is capable of maintaining the spectral quality of the measured sky spectrum to 1 part in 10 3 over the full band and outperforms conventional broadband antennas by at least an order of magnitude. While this is not sufficient to make a direct detection of the cosmological recombination radiation, it meets the baseline design criteria for an experiment that can make an absolute measurement of the sky spectrum at the millikelvin level, thereby making it capable of improving foreground models to global signal detection experiments (including those from cosmic dawn and the epoch of reionization) and addressing the problem of the excess radio background at 3.3 GHz reported by the ARCADE2 experiment.
Description:	Open Access
URI:	http://hdl.handle.net/2289/8292
Alternative Location:	https://ui.adsabs.harvard.edu/abs/2024AJ....168...39S/abstract https://inspirehep.net/literature/2803299 https://doi.org/10.3847/1538-3881/ad4a74
Copyright:	2024 The Author(s)
Appears in Collections:	Research Papers (A&A)

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