Euclid preparation XX. the Complete Calibration of the Color-Redshift Relation survey : LBT observations and data release

R. Saglia, S. De Nicola, M. Fabricius, V. Guglielmo, J. Snigula, R. Zöller, R. Bender, J. Heidt, D. Masters, D. Stern, S. Paltani, A. Amara, N. Auricchio, M. Baldi, C. Bodendorf, D. Bonino, E. Branchini, M. Brescia, J. Brinchmann, S. CameraV. Capobianco, C. Carbone, J. Carretero, M. Castellano, S. Cavuoti, R. Cledassou, G. Congedo, C. J. Conselice, L. Conversi, Y. Copin, L. Corcione, F. Courbin, M. Cropper, A. Da Silva, H. Degaudenzi, M. Douspis, F. Dubath, C. A.J. Duncan, X. Dupac, S. Dusini, S. Farrens, M. Frailis, E. Franceschi, S. Galeotta, B. Garilli, S. M. Niemi, P. Schneider, Y. Wang, G. Gozaliasl, A. G. Sánchez, Euclid Collaboration

Research output: Contribution to journalArticleScientific

4 Citations (Scopus)

Abstract

The Complete Calibration of the Color-Redshift Relation survey (C3R2) is a spectroscopic program designed to empirically calibrate the galaxy color-redshift relation to the Euclid depth (IE = 24.5), a key ingredient for the success of Stage IV dark energy projects based on weak lensing cosmology. A spectroscopic calibration sample that is as representative as possible of the galaxies in the Euclid weak lensing sample is being collected, selecting galaxies from a self-organizing map (SOM) representation of the galaxy color space. Here, we present the results of a nearinfrared H- and K-band spectroscopic campaign carried out using the LUCI instruments at the LBT. For a total of 251 galaxies, we present new highly reliable redshifts in the 1.3 ≤ z ≤ 1.7 and 2 ≤ z ≤ 2.7 ranges. The newly-determined redshifts populate 49 SOM cells that previously contained no spectroscopic measurements and almost twice the occupation numbers of an additional 153 SOM cells. A final optical ground-based observational effort is needed to calibrate the missing cells, in particular in the redshift range 1.7 ≤ z ≤ 2.7, which lack spectroscopic calibration. In the end, Euclid itself will deliver telluric-free near-IR spectra that can complete the calibration.

Original languageEnglish
Article numberA196
JournalAstronomy and Astrophysics
Volume664
DOIs
Publication statusPublished - Aug 2022
MoE publication typeB1 Non-refereed journal articles

Keywords

  • catalogs
  • Galaxies: distances and redshifts
  • surveys

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