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arXiv · 2004.01448

A tomographic map of the large-scale matter distribution using the eBOSS Stripe 82 Ly-$\alpha$ forest

C. Ravoux·E. Armengaud·M. Walther·T. Etourneau·D. Pomarède·N. Palanque-Delabrouille·C. Yèche·J. Bautista·H. du Mas des Bourboux·S. Chabanier·K. Dawson·J. -M. Le Goff·B. Lyke·A. D. Myers·P. Petitjean·M. M. Pieri·J. Rich·G. Rossi·D. P. Schneider
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Abstract

The Lyman-$\alpha$ (hereafter Ly-$\alpha$) forest is a probe of large-scale matter density fluctuations at high redshift, $z > 2.1$. It consists of HI absorption spectra along individual lines-of-sight. If the line-of-sight density is large enough, 3D maps of HI absorption can be inferred by tomographic reconstruction. In this article, we investigate the Ly-$\alpha$ forest available in the Stripe 82 field ($220\,\mathrm{deg^{2}}$), based on the quasar spectra from SDSS Data Release DR16. The density of observed quasar spectra is $37\,\mathrm{deg^{-2}}$ with a mean pixel signal-to-noise ratio of two per angstrom. This study provides an intermediate case between the average SDSS density and that of the much denser but smaller CLAMATO survey. We derive a 3D map of large-scale matter fluctuations from these data, using a Wiener filter technique. The total volume of the map is $0.94\,\mathrm{h^{-3} Gpc^{3}}$. Its resolution is $13\,\mathrm{h^{-1} Mpc}$, which is related to the mean transverse distance between nearest lines-of-sight. From this map, we provide a catalog of voids and protocluster candidates in the cosmic web. The map-making and void catalog are compared to simulated eBOSS Stripe 82 observations. A stack over quasar positions provides a visualization of the Ly-$\alpha$ quasar cross-correlation. This tomographic reconstruction constitutes the largest-volume high-redshift 3D map of matter fluctuations.

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C. Ravoux, E. Armengaud, M. Walther, T. Etourneau, D. Pomarède, N. Palanque-Delabrouille, C. Yèche, J. Bautista, H. du Mas des Bourboux, S. Chabanier, K. Dawson, J. -M. Le Goff, B. Lyke, A. D. Myers, P. Petitjean, M. M. Pieri, J. Rich, G. Rossi, D. P. Schneider. 2020-04-03. A tomographic map of the large-scale matter distribution using the eBOSS Stripe 82 Ly-$\alpha$ forest. https://doi.org/10.1088/1475-7516/2020/07/010

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