TY - JOUR
T1 - A Bayesian calibration framework for EDGES
AU - Murray, Steven G.
AU - Bowman, Judd D.
AU - Sims, Peter H.
AU - Mahesh, Nivedita
AU - Rogers, Alan E.E.
AU - Monsalve, Raul A.
AU - Samson, Titu
AU - Vydula, Akshatha Konakondula
N1 - Publisher Copyright:
© 2022 The Author(s)
PY - 2022/12/1
Y1 - 2022/12/1
N2 - We develop a Bayesian model that jointly constrains receiver calibration, foregrounds, and cosmic 21 cm signal for the EDGES global 21 cm experiment. This model simultaneously describes calibration data taken in the lab along with sky-data taken with the EDGES low-band antenna. We apply our model to the same data (both sky and calibration) used to report evidence for the first star formation in 2018. We find that receiver calibration does not contribute a significant uncertainty to the inferred cosmic signal (< 1 per cent), though our joint model is able to more robustly estimate the cosmic signal for foreground models that are otherwise too inflexible to describe the sky data. We identify the presence of a significant systematic in the calibration data, which is largely avoided in our analysis, but must be examined more closely in future work. Our likelihood provides a foundation for future analyses in which other instrumental systematics, such as beam corrections and reflection parameters, may be added in a modular manner.
AB - We develop a Bayesian model that jointly constrains receiver calibration, foregrounds, and cosmic 21 cm signal for the EDGES global 21 cm experiment. This model simultaneously describes calibration data taken in the lab along with sky-data taken with the EDGES low-band antenna. We apply our model to the same data (both sky and calibration) used to report evidence for the first star formation in 2018. We find that receiver calibration does not contribute a significant uncertainty to the inferred cosmic signal (< 1 per cent), though our joint model is able to more robustly estimate the cosmic signal for foreground models that are otherwise too inflexible to describe the sky data. We identify the presence of a significant systematic in the calibration data, which is largely avoided in our analysis, but must be examined more closely in future work. Our likelihood provides a foundation for future analyses in which other instrumental systematics, such as beam corrections and reflection parameters, may be added in a modular manner.
KW - cosmology: observations
KW - dark ages, reionization, first stars
KW - methods: statistical
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U2 - 10.1093/mnras/stac2600
DO - 10.1093/mnras/stac2600
M3 - Article
AN - SCOPUS:85144806541
SN - 0035-8711
VL - 517
SP - 2264
EP - 2284
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 2
ER -