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arXiv · 2510.08815

LATIS Data Release: $\sim4200$ Spectra of $z \sim 2-3$ Galaxies, Redshifts, and Intergalactic Medium Tomography Maps

Andrew B. Newman·Gwen C. Rudie·Guillermo A. Blanc·Daniel D. Kelson·Nima Chartab·Enrico Congiu·Victoria Pérez·Mahdi Qezlou·Simeon Bird·Brian C. Lemaux·Olga Cucciati
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Abstract

We present the data release of the Ly$\alpha$ 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$\alpha$ 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.

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Andrew B. Newman, Gwen C. Rudie, Guillermo A. Blanc, Daniel D. Kelson, Nima Chartab, Enrico Congiu, Victoria Pérez, Mahdi Qezlou, Simeon Bird, Brian C. Lemaux, Olga Cucciati. 2025-10-09. LATIS Data Release: $\sim4200$ Spectra of $z \sim 2-3$ Galaxies, Redshifts, and Intergalactic Medium Tomography Maps. https://doi.org/10.3847/1538-4365%2Fae0cc5

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