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The Simons Observatory: science goals and forecasts
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Antal upphovsmän: 2492019 (Engelska)Ingår i: Journal of Cosmology and Astroparticle Physics, ISSN 1475-7516, E-ISSN 1475-7516, nr 2, artikel-id 056Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The Simons Observatory (SO) is a new cosmic microwave background experiment being built on Cerro Toco in Chile, due to begin observations in the early 2020s. We describe the scientific goals of the experiment, motivate the design, and forecast its performance. SO will measure the temperature and polarization anisotropy of the cosmic microwave background in six frequency bands centered at: 27, 39, 93, 145, 225 and 280 GHz. The initial con figuration of SO will have three small-aperture 0.5-m telescopes and one large-aperture 6-m telescope, with a total of 60,000 cryogenic bolometers. Our key science goals are to characterize the primordial perturbations, measure the number of relativistic species and the mass of neutrinos, test for deviations from a cosmological constant, improve our understanding of galaxy evolution, and constrain the duration of reionization. The small aperture telescopes will target the largest angular scales observable from Chile, mapping approximate to 10% of the sky to a white noise level of 2 mu K-arcmin in combined 93 and 145 GHz bands, to measure the primordial tensor-to-scalar ratio, r, at a target level of sigma(r) = 0.003. The large aperture telescope will map approximate to 40% of the sky at arcminute angular resolution to an expected white noise level of 6 mu K-arcmin in combined 93 and 145 GHz bands, overlapping with the majority of the Large Synoptic Survey Telescope sky region and partially with the Dark Energy Spectroscopic Instrument. With up to an order of magnitude lower polarization noise than maps from the Planck satellite, the high-resolution sky maps will constrain cosmological parameters derived from the damping tail, gravitational lensing of the microwave background, the primordial bispectrum, and the thermal and kinematic Sunyaev-Zel'dovich effects, and will aid in delensing the large-angle polarization signal to measure the tensor-to-scalar ratio. The survey will also provide a legacy catalog of 16,000 galaxy clusters and more than 20,000 extragalactic sources.

Ort, förlag, år, upplaga, sidor
2019. nr 2, artikel-id 056
Nyckelord [en]
CMBR experiments, CMBR polarisation, cosmological parameters from CMBR
Nationell ämneskategori
Astronomi, astrofysik och kosmologi
Forskningsämne
fysik
Identifikatorer
URN: urn:nbn:se:su:diva-167547DOI: 10.1088/1475-7516/2019/02/056ISI: 000459991200002OAI: oai:DiVA.org:su-167547DiVA, id: diva2:1304896
Tillgänglig från: 2019-04-15 Skapad: 2019-04-15 Senast uppdaterad: 2020-01-23Bibliografiskt granskad
Ingår i avhandling
1. Probing the early Universe with B-mode polarization: The Spider instrument, optical modelling and non-Gaussianity
Öppna denna publikation i ny flik eller fönster >>Probing the early Universe with B-mode polarization: The Spider instrument, optical modelling and non-Gaussianity
2019 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

One of the main goals of modern observational cosmology is to constrain or detect a stochastic background of primordial gravitational waves. The existence of such a background is a generic prediction of the inflationary paradigm: the leading explanation for the universe's initial perturbations. A detection of the gravitational wave signal would provide strong evidence for the paradigm and would amount to an indirect probe of an energy scale far beyond that of conventional physics. Several dedicated experiments search for the signal by performing highly accurate measurements of a unique probe of the primordial gravitational wave background: the B-mode signature in the polarization of the cosmic microwave background (CMB) radiation. A part of this thesis is devoted to one of these experiments: the balloon-borne Spider instrument. The analysis of the first dataset, obtained in two (95 and 150 GHz) frequency bands during a January 2015 Antarctic flight, is described, along with details on the characterisation of systematic signal and the calibration of the instrument. The case of systematic signal due to poorly understood optical properties is treated in more detail. In the context of upcoming experiments, a study of systematic optical effects is presented as well as a numerically efficient method to consistently propagate such effects through an analysis pipeline. This is achieved by a `beam convolution' algorithm capable of simulating the contribution from the entire sky, weighted by the optical response, to the instrument's time-ordered data. It is described how the algorithm can be employed to forecast the performance of upcoming CMB experiments. In the final part of the thesis, an additional use of upcoming B-mode data is described. Constraints on the non-Gaussian correlation between the large-angular-scale B-mode field and the CMB temperature or E-mode anisotropies on small angular scales constitute a rigorous consistency check of the inflationary paradigm. An efficient statistical estimation procedure, a generalised bispectrum estimator, is derived and the constraining power of upcoming CMB data is explored.

Ort, förlag, år, upplaga, sidor
Stockholm: Department of Physics, Stockholm University, 2019
Nyckelord
cosmic microwave background, early universe, polarimetry, telescopes
Nationell ämneskategori
Astronomi, astrofysik och kosmologi
Forskningsämne
fysik
Identifikatorer
urn:nbn:se:su:diva-171284 (URN)978-91-7797-799-5 (ISBN)978-91-7797-800-8 (ISBN)
Disputation
2019-09-20, sal FD41, AlbaNova universitetscentrum, Roslagstullsbacken 21, Stockholm, 13:00 (Engelska)
Opponent
Handledare
Anmärkning

At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 1: Manuscript.

Tillgänglig från: 2019-08-28 Skapad: 2019-08-12 Senast uppdaterad: 2019-08-20Bibliografiskt granskad

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Duivenvoorden, AdriFreese, KatherineFuller, GeorgeGhersi, Jose Tomas GalvezGudmundsson, Jon E.Madhavacheril, MathewStein, GeorgeTucker, CaroleVagnozzi, SunnyWollack, Edward J.
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FysikumOskar Klein-centrum för kosmopartikelfysik (OKC)
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Journal of Cosmology and Astroparticle Physics
Astronomi, astrofysik och kosmologi

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