Michael Walther, Nils Schöneberg, Solène Chabanier, Eric Armengaud, Jean Sexton, Christophe Yèche, Julien Lesgourgues, Markus R. Mosbech, Corentin Ravoux, Nathalie Palanque-Delabrouille and Zarija Lukić
{"title":"从宇宙学模拟中模拟莱曼-阿尔法森林一维功率谱:来自eBOSS测量的新模型和约束","authors":"Michael Walther, Nils Schöneberg, Solène Chabanier, Eric Armengaud, Jean Sexton, Christophe Yèche, Julien Lesgourgues, Markus R. Mosbech, Corentin Ravoux, Nathalie Palanque-Delabrouille and Zarija Lukić","doi":"10.1088/1475-7516/2025/05/099","DOIUrl":null,"url":null,"abstract":"We present the Lyssa suite of high-resolution cosmological simulations of the Lyman-α forest designed for cosmological analyses. These 18 simulations have been run using the Nyx code with 40963 hydrodynamical cells in a 120 Mpc (∼ 81 Mpc/h) comoving box and individually provide sub-percent level convergence of the Lyman-α forest 1d flux power spectrum. We build a Gaussian process emulator for the Lyssa simulations in the lym1d likelihood framework to interpolate the power spectrum at arbitrary parameter values. We validate this emulator based on leave-one-out tests and based on the parameter constraints for simulations outside of the training set. We also perform comparisons with a previous emulator, showing a percent level accuracy and a good recovery of the expected cosmological parameters. Using this emulator we derive constraints on the linear matter power spectrum amplitude and slope parameters ALyα and nLyα. While the best-fit Planck ΛCDM model has ALyα = 8.79 and nLyα = -2.363, from DR14 eBOSS data we find that ALyα < 7.6 (95% CI) and nLyα = -2.369 ± 0.008. The low value of ALyα, in tension with Planck, is driven by the correlation of this parameter with the mean transmission of the Lyman-α forest. This tension disappears when imposing a well-motivated external prior on this mean transmission, in which case we find ALyα = 9.8 ± 1.1 in accordance with Planck.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"26 1","pages":""},"PeriodicalIF":5.3000,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Emulating the Lyman-Alpha forest 1D power spectrum from cosmological simulations: new models and constraints from the eBOSS measurement\",\"authors\":\"Michael Walther, Nils Schöneberg, Solène Chabanier, Eric Armengaud, Jean Sexton, Christophe Yèche, Julien Lesgourgues, Markus R. 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Using this emulator we derive constraints on the linear matter power spectrum amplitude and slope parameters ALyα and nLyα. While the best-fit Planck ΛCDM model has ALyα = 8.79 and nLyα = -2.363, from DR14 eBOSS data we find that ALyα < 7.6 (95% CI) and nLyα = -2.369 ± 0.008. The low value of ALyα, in tension with Planck, is driven by the correlation of this parameter with the mean transmission of the Lyman-α forest. 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Emulating the Lyman-Alpha forest 1D power spectrum from cosmological simulations: new models and constraints from the eBOSS measurement
We present the Lyssa suite of high-resolution cosmological simulations of the Lyman-α forest designed for cosmological analyses. These 18 simulations have been run using the Nyx code with 40963 hydrodynamical cells in a 120 Mpc (∼ 81 Mpc/h) comoving box and individually provide sub-percent level convergence of the Lyman-α forest 1d flux power spectrum. We build a Gaussian process emulator for the Lyssa simulations in the lym1d likelihood framework to interpolate the power spectrum at arbitrary parameter values. We validate this emulator based on leave-one-out tests and based on the parameter constraints for simulations outside of the training set. We also perform comparisons with a previous emulator, showing a percent level accuracy and a good recovery of the expected cosmological parameters. Using this emulator we derive constraints on the linear matter power spectrum amplitude and slope parameters ALyα and nLyα. While the best-fit Planck ΛCDM model has ALyα = 8.79 and nLyα = -2.363, from DR14 eBOSS data we find that ALyα < 7.6 (95% CI) and nLyα = -2.369 ± 0.008. The low value of ALyα, in tension with Planck, is driven by the correlation of this parameter with the mean transmission of the Lyman-α forest. This tension disappears when imposing a well-motivated external prior on this mean transmission, in which case we find ALyα = 9.8 ± 1.1 in accordance with Planck.
期刊介绍:
Journal of Cosmology and Astroparticle Physics (JCAP) encompasses theoretical, observational and experimental areas as well as computation and simulation. The journal covers the latest developments in the theory of all fundamental interactions and their cosmological implications (e.g. M-theory and cosmology, brane cosmology). JCAP''s coverage also includes topics such as formation, dynamics and clustering of galaxies, pre-galactic star formation, x-ray astronomy, radio astronomy, gravitational lensing, active galactic nuclei, intergalactic and interstellar matter.