<i>Euclid</i>preparation

Journal article

The Complete Calibration of the Color-Redshift Relation survey (C3R2) is a spectroscopic programme designed to empirically calibrate the galaxy color-redshift relation to the Euclid depth (I_E=24.5), a key ingredient for the success of Stage IV dark energy projects based on weak lensing cosmology. A spectroscopic calibration sample 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 near-infrared H- and K-bands 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 which previously contained no spectroscopic measurements and almost double 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 that lack spectroscopic calibration. In the end, Euclid itself will deliver telluric-free NIR spectra that can complete the calibration...

Authors: Saglia, R; De Nicola, S; Fabricius, M; Guglielmo, V; Snigula, J

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: EDP Sciences
• Journal: Astronomy & Astrophysics
• Volume: 664
• Pages: A196-A196
• Publication date: 2022-06-25
• Acceptance date: 2022-06-01
• DOI: 10.1051/0004-6361/202243604
• EISSN: 1432-0746
• ISSN: 0004-6361
• Language: English
• Keywords: Redshift; Astronomy; Astrophysics; Calibration; Physics; Cosmology; Redshift survey; Photometric redshift; Weak gravitational lensing; Galaxy