COSMOS Spectroscopic Redshift Compilation (First Data Release): 488,000 Redshifts Encompassing Two Decades of Spectroscopy
/ Authors
A. Khostovan, J. Kartaltepe, M. Salvato, O. Ilbert, Caitlin M. Casey, H. Algera, J. Antwi-Danso, A. Battisti, M. Brinch, M. Brusa
and 43 more authors
A. Calabró, P. Capak, N. Chartab, O. Cooper, I. Cox, B. Darvish, N. Drakos, A. Faisst, Matthew R. George, G. Gozaliasl, S. Harish, G. Hasinger, H. Hatamnia, A. Iovino, S. Jin, D. Kashino, A. Koekemoer, Ronaldo Laishram, K. Lee, Jitrapon Lertprasertpong, S. Lilly, D. Masters, B. Mobasher, T. Nagao, Masato Onodera, Yingjie Peng, D. Sanders, R. Sanders, Z. Sattari, N. Scoville, Ekta A. Shah, J. Silverman, Nao Suzuki, Masayuki Tanaka, S. Toft, B. Trakhtenbrot, J. Trump, Mattia Vaccari, F. Valentino, B. Vanderhoof, J. Weaver, Min S. Yun, J. Zavala
/ Abstract
We present the COSMOS Spectroscopic Redshift Compilation encompassing ∼20 yr of spectroscopic redshifts within a 10 deg2 area centered on the 2 deg2 COSMOS legacy field. This compilation contains 487,666 redshifts of 266,284 unique objects from 138 individual programs up to z ∼ 8 with median stellar mass ∼108.4–1010 M⊙ (redshift dependent). Rest-frame NUVrJ colors and star formation rate–stellar mass correlations show that the compilation primarily contains low-to-intermediate-mass star-forming and massive, quiescent galaxies at z < 1.25 and mostly low-mass bursty star-forming galaxies at z > 2. Sources in the compilation cover a diverse range of environments, including protoclusters such as “Hyperion.” The full compilation is 50% spectroscopically complete by i ∼ 23.4 mag and Ks ∼ 21.6 mag; however, this is redshift dependent. Spatially, the compilation is >50% (>30%) complete within the central (outer) region limited to i < 24 mag and Ks < 22.5 mag, separately. We demonstrate how the compilation can be used to validate photometric redshifts and investigate calibration metrics. By training self-organizing maps on COSMOS2020/Classic and projecting the compilation onto it, we find key subpopulations currently lacking spectroscopic coverage, including z < 1 intermediate-mass quiescent and low-/intermediate-mass bursty star-forming galaxies, z ∼ 2 massive quiescent galaxies, and z > 3 massive star-forming galaxies. This highlights how combining self-organizing maps with our compilation can provide guidance for future spectroscopic observations to get a complete spectroscopic view of galaxy populations. Lastly, the compilation will undergo periodic data releases incorporating new spectroscopic redshifts and providing a lasting legacy resource for the community.
Journal: The Astrophysical Journal Supplement Series