In:
Journal of Cosmology and Astroparticle Physics, IOP Publishing, Vol. 2023, No. 06 ( 2023-06-01), p. 034-
Kurzfassung:
PICO is a concept for a NASA probe-scale mission aiming to detect or constrain the tensor to scalar ratio r , a parameter that quantifies the amplitude of inflationary gravity waves.
We carry out map-based component separation on simulations with five foreground models and input r values r in = 0 and r in = 0.003. We forecast r determinations using a Gaussian likelihood assuming either no delensing or a residual lensing factor A lens = 27%. By implementing the first full-sky, post component-separation, map-domain delensing, we show that PICO should be able to achieve A lens = 22% – 24%. For four of the five foreground models we find that PICO would be able to set the constraints r 〈 1.3 × 10 -4 to r 〈 2.7 × 10 -4 (95%) if r in = 0, the strongest constraints of any foreseeable instrument. For these models, r = 0.003 is recovered with confidence levels between 18 σ and 27 σ . We find weaker, and in some cases significantly biased, upper limits when removing few low or high frequency bands. The fifth model gives a 3 σ detection when r in = 0 and a 3 σ bias with r in = 0.003. However, by correlating r determinations from many small 2.5% sky areas with the mission's 555 GHz data we identify and mitigate the bias. This analysis underscores the importance of large sky coverage. We show that when only low multipoles ℓ ≤ 12 are used, the non-Gaussian shape of the true likelihood gives uncertainties that are on average 30% larger than a Gaussian approximation.
Materialart:
Online-Ressource
ISSN:
1475-7516
DOI:
10.1088/1475-7516/2023/06/034
Sprache:
Unbekannt
Verlag:
IOP Publishing
Publikationsdatum:
2023
ZDB Id:
2104147-7
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