Combining Dark Energy Survey Science Verification data with near-infrared data from the ESO VISTA Hemisphere Survey

Date

2015

Authors

Banerji, M.
Jouvel, S.
Lin, Huan
McMahon, R. G.
Lahav, O.
Castander, F. J.
Abdalla, Filipe B.
Bertin, E.
Bosman, S. E.
Carnero, A.

Journal Title

Journal ISSN

Volume Title

Publisher

Blackwell Publishing Ltd

Abstract

We present the combination of optical data from the Science Verification phase of the Dark Energy Survey (DES) with near-infrared (NIR) data from the European Southern Observatory VISTA Hemisphere Survey (VHS). The deep optical detections from DES are used to extract fluxes and associated errors from the shallower VHS data. Joint seven-band (grizYJK) photometric catalogues are produced in a single 3 sq-deg dedicated camera field centred at 02h26m−04d36m where the availability of ancillary multiwavelength photometry and spectroscopy allows us to test the data quality. Dual photometry increases the number of DES galaxies with measured VHS fluxes by a factor of ∼4.5 relative to a simple catalogue level matching and results in a ∼1.5 mag increase in the 80 per cent completeness limit of the NIR data. Almost 70 per cent of DES sources have useful NIR flux measurements in this initial catalogue. Photometric redshifts are estimated for a subset of galaxies with spectroscopic redshifts and initial results, although currently limited by small number statistics, indicate that the VHS data can help reduce the photometric redshift scatter at both z < 0.5 and z > 1. We present example DES+VHS colour selection criteria for high-redshift luminous red galaxies (LRGs) at z ∼ 0.7 as well as luminous quasars. Using spectroscopic observations in this field we show that the additional VHS fluxes enable a cleaner selection of both populations with <10 per cent contamination from galactic stars in the case of spectroscopically confirmed

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Citation

Source

Monthly Notices of the Royal Astronomical Society

Type

Journal article

Book Title

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Access Statement

Open Access

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DOI

10.1093/mnras/stu2261

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