J/A+A/570/A11 The Hawk-I UDS and GOODS Survey (HUGS) (Fontana+, 2014)
The Hawk-I UDS and GOODS Survey (HUGS):
Survey design and deep K-band number counts.
Fontana A., Dunlop J.S., Paris D., Targett T.A., Boutsia K., Castellano M.,
Galametz A., Grazian A., McLure R., Merlin E., Pentericci L., Wuyts S.,
Almaini O., Caputi K., Chary R.-R., Cirasuolo M., Conselice C.J., Cooray A.,
Daddi E., Dickinson M., Faber S.M., Fazio G., Ferguson H.C., Giallongo E.,
Giavalisco M., Grogin N.A., Hathi N., Koekemoer A.M., Koo D.C., Lucas R.A.,
Nonino M., Rix H.W., Renzini A., Rosario D., Santini P., Scarlata C.,
Sommariva V., Stark D.P., van der Wel A., Vanzella E., Wild V., Yan H.,
Zibetti S.
<Astron. Astrophys. 570, A11 (2014)>
=2014A&A...570A..11F 2014A&A...570A..11F
ADC_Keywords: Surveys ; Galaxies, photometry ; Galaxy catalogs
Keywords: surveys - galaxies: evolution
Abstract:
We present the results of a new, ultra-deep, near-infrared imaging
survey executed with the Hawk-I imager at the ESO VLT, of which we
make all the data (images and catalog) public. This survey, named HUGS
(Hawk-I UDS and GOODS Survey), provides deep, high-quality imaging in
the K and Y bands over the portions of the UKIDSS UDS and GOODS-South
fields covered by the CANDELS HST WFC3/IR survey. In this paper we
describe the survey strategy, the observational campaign, the data
reduction process, and the data quality. We show that, thanks to
exquisite image quality and extremely long exposure times, HUGS
delivers the deepest K-band images ever collected over areas of
cosmological interest, and in general ideally complements the CANDELS
data set in terms of image quality and depth. In the GOODS-S field,
the K-band observations cover the whole CANDELS area with a complex
geometry made of 6 different, partly overlapping pointings, in order
to best match the deep and wide areas of CANDELS imaging. In the
deepest region (which includes most of the Hubble Ultra Deep Field)
exposure times exceed 80 hours of integration, yielding a 1-σ
magnitude limit per square arcsec of ~=28.0ABmag. The seeing is
exceptional and homogeneous across the various pointings, confined to
the range 0.38-0.43arcsec. In the UDS field the survey is about one
magnitude shallower (to match the correspondingly shallower depth of
the CANDELS images) but includes also Y-band band imaging (which, in
the UDS, was not provided by the CANDELS WFC3/IR imaging). In the
K-band, with an average exposure time of 13 hours, and seeing in the
range 0.37-0.43arcsec, the 1-σ limit per square arcsec in the
UDS imaging is ~=27.3ABmag. In the Y-band, with an average exposure
time ~=8h, and seeing in the range 0.45-0.5arcsec, the imaging yields
a 1-σ limit per square arcsec of ~=28.3ABmag. We show that the
HUGS observations are well matched to the depth of the CANDELS WFC3/IR
data, since the majority of even the faintest galaxies detected in the
CANDELS H-band images are also detected in HUGS. Finally we present
the K-band galaxy number counts produced by combining the HUGS data
from the two fields. We show that the slope of the number counts
depends sensitively on the assumed distribution of galaxy sizes, with
potential impact on the estimated extra-galactic background light.
Description:
K-band galaxy number counts derived from the HUGS survey, corrected
for incompleteness and other systematic effects as described in the
text. Number densities are in units of galaxies per magnitude per
square degree. Columns 2 and 3 assume unresolved morphologies for
galaxies. Columns 4 and 5 assume a distributions of galaxy half-light
radius from 0.1arcsec to 0.3arcsec.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
hugs.dat 41 42 *K-band galaxy number counts derived from the
HUGS survey (table3)
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Note on hugs.dat: corrected for incompleteness and other systematic effects as
described in the text.
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See also:
http://www.astrodeep.eu/HUGS/ : HUGS Home Page
Byte-by-byte Description of file: hugs.dat
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Bytes Format Units Label Explanations
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1- 5 F5.2 mag mag [16.26.25] AB magnitude (center of bin)
9- 14 F6.4 [1/mag/deg2] log(N) Galaxy number counts in galaxies/mag/deg2,
assuming point like morphology (1)
18- 23 F6.4 [1/mag/deg2] log(e_N) Galaxy number counts error (1)
27- 32 F6.4 [1/mag/deg2] log(N)b Galaxy number counts in galaxies/mag/deg2,
assuming extended morphology (2)
36- 41 F6.4 [1/mag/deg2] log(e_N)b Galaxy number counts error (σ) (2)
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Note (1): Counts assuming unresolved morphologies for galaxies.
Note (2): Sounts assuming a distribution of galaxy half-light radius from
0.1arcsec to 0.3arcsec.
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Acknowledgements:
Adriano Fontana, adriano.fontana(at)oa-roma.inaf.it
(End) Patricia Vannier [CDS] 07-Oct-2014