J-NEP: 60-band photometry and photometric redshifts for the James Webb Space Telescope North Ecliptic Pole Time-Domain Field

Abstract

The J-PAS survey will observe ~1/3 of the northern sky with a set of 56 narrow-band filters using the dedicated 2.55 m JST telescope at the Javalambre Astrophysical Observatory. Prior to the installation of the main camera, in order to demonstrate the scientific potential of J-PAS, two small surveys were performed with the single-CCD Pathfinder camera: miniJPAS (~1 deg2 along the Extended Groth Strip), and J-NEP (~0.3 deg2 around the JWST North Ecliptic Pole Time Domain Field), including all 56 J-PAS filters as well as u, g, r, and i. J-NEP is ~0.5-1.0 magnitudes deeper than miniJPAS, providing photometry for 24,618 r-band detected sources and photometric redshifts (photo-z) for the 6,662 sources with r<23. In this paper we describe the photometry and photo-z of J-NEP and demonstrate a new method for the removal of systematic offsets in the photometry based on the median colours of galaxies, dubbed "galaxy locus recalibration". This method does not require spectroscopic observations except in a few reference pointings and, unlike previous methods, is applicable to the whole J-PAS survey. We use a spectroscopic sample of 787 galaxies to test the photo-z performance for J-NEP and in comparison to miniJPAS. We find that the deeper J-NEP observations result in a factor ~1.5-2 decrease in sigma_NMAD (a robust estimate of the standard deviation of the photo-z error) and the outlier rate relative to miniJPAS for r>21.5 sources, but no improvement in brighter ones. We find the same relation between sigma_NMAD and odds in J-NEP and miniJPAS, suggesting sigma_NMAD can be predicted for any set of J-PAS sources from their odds distribution alone, with no need for additional spectroscopy to calibrate the relation. We explore the causes for photo-z outliers and find that colour-space degeneracy at low S/N, photometry artifacts, source blending, and exotic spectra are the most important factors.

16 pages, 25 figures, accepted for publication in Astronomy and Astrophysics

References in corpus (18)

• Galaxies in the Hubble Ultra Deep Field: I. Detection, Multiband Photometry, Photometric Redshifts, and Morphology
• JWST's PEARLS: Prime Extragalactic Areas for Reionization and Lensing Science: Project Overview and First Results
• Binospec: A Wide-field Imaging Spectrograph for the MMT
• The miniJPAS survey: a preview of the Universe in 56 colours
• Optimal filter systems for photometric redshift estimation
• The miniJPAS survey: star-galaxy classification using machine learning
• Binospec Software System
• The miniJPAS survey: Identification and characterization of galaxy populations with the J-PAS photometric system
• The miniJPAS survey: the photometric redshift catalogue
• The miniJPAS survey: The role of group environment in quenching the star formation
• The JCMT SCUBA-2 Survey of the James Webb Space Telescope North Ecliptic Pole Time-Domain Field
• J-PAS: Measuring emission lines with artificial neural networks
• The miniJPAS survey: Identification and characterization of the emission line galaxies down to $z<0.35$ in the AEGIS field
• The NuSTAR Extragalactic Survey of the James Webb Space Telescope North Ecliptic Pole Time-Domain Field
• TOPz: Photometric redshifts for J-PAS
• The miniJPAS survey: The galaxy populations in the most massive cluster in miniJPAS, mJPC2470-1771
• Black hole virial masses from single-epoch photometry: the miniJPAS test case
• The miniJPAS Survey: A Study on Wavelength Dependence of the Photon Response Non-uniformity of the JPAS-{\it Pathfinder} Camera

Cited by in corpus (8)

• PEARLS: NuSTAR and XMM-Newton Extragalactic Survey of the JWST North Ecliptic Pole Time-Domain Field II
• The miniJPAS & J-NEP surveys: Identification and characterization of the Ly$\alpha$ Emitter population and the Ly$\alpha$ Luminosity Function
• The miniJPAS survey. Evolution of the luminosity and stellar mass functions of galaxies up to $z\sim 0.7$
• The PAU Survey: The quasar UV and Ly$\alpha$ luminosity functions at $2.7<z<5.3$
• The miniJPAS survey: Maximising the photo-z accuracy from multi-survey datasets with probability conflation
• The miniJPAS and J-NEP surveys: Machine learning for star-galaxy separation
• J-PAS: First Identification, Physical Properties and Ionization Efficiency of Extreme Emission Line Galaxies
• The $N_H$ Distribution of Hard X-ray Selected AGN in the NEP Field