Second Data Release of the COSMOS Lyman-alpha Mapping and Tomographic Observation: The First 3D Maps of the Detailed Cosmic Web at 2.05<z<2.55

TL;DR

This paper presents the second data release of the CLAMATO survey, providing the first 3D maps of the cosmic web at redshifts 2.05 to 2.55 using Lyman-alpha forest absorption to trace intergalactic hydrogen and dark matter.

Contribution

It introduces a new large-scale 3D mapping of the cosmic web at high redshift using Lyman-alpha forest data and infers the underlying dark matter distribution through a novel forward modeling approach.

Findings

Reconstructed detailed 3D maps of the cosmic web at z~2.05-2.55.

Demonstrated consistency between inferred over-densities and galaxy survey data.

Provided publicly accessible data and interactive models for further research.

Abstract

We present the second data release of the COSMOS Lyman-Alpha Mapping And Tomography Observations (CLAMATO) Survey conducted with the LRIS spectrograph on the Keck-I telescope. This project used Lyman-alpha forest absorption in the spectra of faint star forming galaxies and quasars at z ~ 2-3 to trace neutral hydrogen in the intergalactic medium. In particular, we use 320 objects over a footprint of ~0.2 deg^2 to reconstruct the absorption field at 2.05 < z < 2.55 at ~2 h^{-1}Mpc resolution. We apply a Wiener filtering technique to the observed data to reconstruct three dimensional maps of the field over a volume of 4.1 x 10^5 comoving cubic Mpc. In addition to the filtered flux maps, for the first time we infer the underlying dark matter field through a forward modeling framework from a joint likelihood of galaxy and Lyman-alpha forest data, finding clear examples of the detailed cosmic web consisting of cosmic voids, sheets, filaments, and nodes. In addition to traditional figures, we present a number of interactive three dimensional models to allow exploration of the data and qualitative comparisons to known galaxy surveys. We find that our inferred over-densities are consistent with those found from galaxy fields. Our reduced spectra, extracted Lyman-alpha forest pixel data, and reconstructed tomographic maps are available publicly at https://doi.org/10.5281/zenodo.7524313