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An emulator for the...
An emulator for the Lyman-alpha forest
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Bird, Simeon (författare)
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- Rogers, Keir K. (författare)
- Stockholms universitet,Fysikum,Oskar Klein-centrum för kosmopartikelfysik (OKC)
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- Peiris, Hiranya V. (författare)
- Stockholms universitet,Fysikum,Oskar Klein-centrum för kosmopartikelfysik (OKC)
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Verde, Licia (författare)
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Font-Ribera, Andreu (författare)
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Pontzen, Andrew (författare)
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(creator_code:org_t)
- 2019-02-26
- 2019
- Engelska.
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Ingår i: Journal of Cosmology and Astroparticle Physics. - : IOP Publishing. - 1475-7516. ; :2
- Relaterad länk:
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https://arxiv.org/ab...
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http://arxiv.org/pdf...
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- We present methods for interpolating between the 1-D flux power spectrum of the Lyman-alpha forest, as output by cosmological hydrodynamic simulations. Interpolation is necessary for cosmological parameter estimation due to the limited number of simulations possible. We construct an emulator for the Lyman-alpha forest flux power spectrum from 21 small simulations using Latin hypercube sampling and Gaussian process interpolation. We show that this emulator has a typical accuracy of 1 : 5% and a worst-case accuracy of 4%, which compares well to the current statistical error of 3-5% at z < 3 from BOSS DR9. We compare to the previous state of the art, quadratic polynomial interpolation. The Latin hypercube samples the entire volume of parameter space, while quadratic polynomial emulation samples only lower-dimensional subspaces. The Gaussian process provides an estimate of the emulation error and we show using test simulations that this estimate is reasonable. We construct a likelihood function and use it to show that the posterior constraints generated using the emulator are unbiased. We show that our Gaussian process emulator has lower emulation error than quadratic polynomial interpolation and thus produces tighter posterior confidence intervals, which will be essential for future Lyman-alpha surveys such as DESI.
Ämnesord
- NATURVETENSKAP -- Fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences (hsv//eng)
Nyckelord
- cosmological simulations
- Lyman alpha forest
- cosmological parameters from LSS
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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