The Next Generation Virgo Cluster Survey. XV. The photometric redshift estimation for background sources

Abstract

The Next Generation Virgo Cluster Survey is an optical imaging survey covering 104 deg^2 centered on the Virgo cluster. Currently, the complete survey area has been observed in the u*giz-bands and one third in the r-band. We present the photometric redshift estimation for the NGVS background sources. After a dedicated data reduction, we perform accurate photometry, with special attention to precise color measurements through point spread function-homogenization. We then estimate the photometric redshifts with the Le Phare and BPZ codes. We add a new prior which extends to iAB = 12.5 mag. When using the u*griz-bands, our photometric redshifts for 15.5 \le i \lesssim 23 mag or zphot \lesssim 1 galaxies have a bias |Δz| < 0.02, less than 5% outliers, and a scatter σ_{outl.rej.} and an individual error on zphot that increase with magnitude (from 0.02 to 0.05 and from 0.03 to 0.10, respectively). When using the u*giz-bands over the same magnitude and redshift range, the lack of the r-band increases the uncertainties in the 0.3 \lesssim zphot \lesssim 0.8 range (-0.05 < Δz < -0.02, σ_{outl.rej} ~ 0.06, 10-15% outliers, and zphot.err. ~ 0.15). We also present a joint analysis of the photometric redshift accuracy as a function of redshift and magnitude. We assess the quality of our photometric redshifts by comparison to spectroscopic samples and by verifying that the angular auto- and cross-correlation function w(θ) of the entire NGVS photometric redshift sample across redshift bins is in agreement with the expectations.

Accepted for publication in ApJS. 24 pages, 21 Figures (some with degraded quality to fit the arxiv size limit), 6 Tables

References in corpus (11)

• EAZY: A Fast, Public Photometric Redshift Code
• COSMOS Photometric Redshifts with 30-bands for 2-deg2
• zCOSMOS: A Large VLT/VIMOS redshift survey covering 0 < z < 3 in the COSMOS field
• Galaxies in the Hubble Ultra Deep Field: I. Detection, Multiband Photometry, Photometric Redshifts, and Morphology
• Calibrating Redshift Distributions Beyond Spectroscopic Limits with Cross-Correlations
• The DEEP2 Galaxy Redshift Survey: The Role of Galaxy Environment in the Cosmic Star-Formation History
• CARS: the CFHTLS-Archive-Research Survey; I. Five-band multi-colour data from 37 sq. deg. CFHTLS-Wide observations
• Photometric Redshifts in the IRAC Shallow Survey
• Robust Machine Learning Applied to Astronomical Datasets III: Probabilistic Photometric Redshifts for Galaxies and Quasars in the SDSS and GALEX
• The Arecibo Legacy Fast ALFA Survey: VI. Second HI Source Catalog of the Virgo Cluster Region
• BLOX: The Bonn Lensing, Optical, and X-ray selected galaxy clusters -- I. Cluster catalog construction

Cited by in corpus (8)

• The fourth data release of the Kilo-Degree Survey: ugri imaging and nine-band optical-IR photometry over 1000 square degrees
• The fifth data release of the Kilo Degree Survey: Multi-epoch optical/NIR imaging covering wide and legacy-calibration fields
• The Next Generation Virgo cluster Survey (NGVS). XXV. Fiducial panchromatic colors of Virgo core globular clusters and their comparison to model predictions
• Weak lensing magnification of SpARCS galaxy clusters
• The 2-degree Field Lensing Survey: photometric redshifts from a large new training sample to r<19.5
• Tightening weak lensing constraints on the ellipticity of galaxy-scale dark matter haloes
• The Next Generation Virgo Cluster Survey. XXVIII. Characterization of the Galactic White Dwarf Population
• The ViCTORIA project: description of a multi-frequency radio survey of the Virgo galaxy cluster