TY - JOUR

T1 - On-sky characterisation of the VISTA NB118 narrow-band filters at 1.19 μ m

AU - Milvang-Jensen, Bo

AU - Freudling, Wolfram

AU - Zabl, Johannes

AU - Fynbo, Johan P. U.

AU - Møller, Palle

AU - Nilsson, Kim K.

AU - McCracken, Henry Joy

AU - Hjorth, Jens

AU - Le Fèvre, Olivier

AU - Tasca, Lidia

AU - Dunlop, James S.

AU - Sobral, David

PY - 2013/12

Y1 - 2013/12

N2 - Observations of the high redshift Universe through narrow-band filters have proven very successful in the last decade. The 4-m VISTA telescope, equipped with the wide-field camera VIRCAM, offers a major step forward in wide-field near-infrared imaging, and in order to utilise VISTA's large field-of-view and sensitivity, the Dark Cosmology Centre provided a set of 16 narrow-band filters for VIRCAM. These NB118 filters are centered at a wavelength near 1.19 μm in a region with few airglow emission lines. The filters allow the detection of Hα emitters at z = 0.8, Hβ and [O iii] emitters at z ≈ 1.4, [O ii] emitters at z = 2.2, and Lyα emitters at z = 8.8. Based on guaranteed time observations of the COSMOS field we here present a detailed description and characterization of the filters and their performance. In particular we provide sky-brightness levels and depths for each of the 16 detector/filter sets and find that some of the filters show signs of some red-leak. We identify a sample of 2 × 103 candidate emission-line objects in the data. Cross-correlating this sample with a large set of galaxies with known spectroscopic redshifts we determine the "in situ" passbands of the filters and find that they are shifted by about 3.5 - 4 nm (corresponding to 30% of the filter width) to the red compared to the expectation based on the laboratory measurements. Finally, we present an algorithm to mask out persistence in VIRCAM data. Scientific results extracted from the data will be presented separately.

AB - Observations of the high redshift Universe through narrow-band filters have proven very successful in the last decade. The 4-m VISTA telescope, equipped with the wide-field camera VIRCAM, offers a major step forward in wide-field near-infrared imaging, and in order to utilise VISTA's large field-of-view and sensitivity, the Dark Cosmology Centre provided a set of 16 narrow-band filters for VIRCAM. These NB118 filters are centered at a wavelength near 1.19 μm in a region with few airglow emission lines. The filters allow the detection of Hα emitters at z = 0.8, Hβ and [O iii] emitters at z ≈ 1.4, [O ii] emitters at z = 2.2, and Lyα emitters at z = 8.8. Based on guaranteed time observations of the COSMOS field we here present a detailed description and characterization of the filters and their performance. In particular we provide sky-brightness levels and depths for each of the 16 detector/filter sets and find that some of the filters show signs of some red-leak. We identify a sample of 2 × 103 candidate emission-line objects in the data. Cross-correlating this sample with a large set of galaxies with known spectroscopic redshifts we determine the "in situ" passbands of the filters and find that they are shifted by about 3.5 - 4 nm (corresponding to 30% of the filter width) to the red compared to the expectation based on the laboratory measurements. Finally, we present an algorithm to mask out persistence in VIRCAM data. Scientific results extracted from the data will be presented separately.

KW - Galaxies: high-redshift

KW - Galaxies: photometry

KW - Instrumentation: photometers

KW - Methods: observational

KW - Techniques: photometric

U2 - 10.1051/0004-6361/201321814

DO - 10.1051/0004-6361/201321814

M3 - Journal article

AN - SCOPUS:84890340346

VL - 560

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

M1 - A94

ER -