LATIS Data Release: $\sim 4200$ Spectra of $z\sim 2-3$ Galaxies, Redshifts, and Intergalactic Medium Tomography Maps

Abstract

We present the data release of the Ly$\hat{I}\pm$ Tomography IMACS Survey (LATIS), one of the largest optical spectroscopic surveys of faint high-redshift galaxies. The survey provides 7408 optical spectra of candidate $z\sim 2-3$ galaxies and QSOs in the Canada-France-Hawaii Telescope Legacy Survey D1, D2 (COSMOS), and D4 fields. The $R\sim 1000$ spectra were obtained using the Inamori Magellan Areal Camera and Spectrograph (IMACS) at the Magellan Baade telescope, with typical integrations of 12 hr. From these spectra, we measured 5575 high-confidence spectroscopic redshifts, of which 4176 are at $z>1.7$, thereby substantially increasing the number of public spectroscopic redshifts at $z\approx 2-3$ in COSMOS and the other survey fields. The data release includes Ly$\hat{I}\pm$ transmission fluctuations measured in $4.7\times 10^5$ pixels, which were used to create 3D maps of the intergalactic medium (IGM) transmission spanning 1.65 deg${}^2$ and $z=2.2-2.8$ at a resolution of 4 $h^{-1}$ cMpc. These are the largest such maps to date and provide a novel tracer of large-scale structure in legacy fields. We also provide ancillary data, including mock surveys. The LATIS data will enable a variety of community studies of galaxy evolution, environments, and the IGM around cosmic noon.

Updated to match published version. Data release available at https://zenodo.org/records/15557327