J/A+A/616/A55 CFHQSIR survey (Pipien+, 2018)
The CFHQSIR survey: a Y-band extension of the CFHTLS-Wide survey.
Pipien S., Basa S., Cuby J.-G., Cuillandre J.-C.,
Willott C., Moutard T., Chatron J., Arnouts S., Hudelot P.
<Astron. Astrophys. 616, A55 (2018)>
=2018A&A...616A..55P 2018A&A...616A..55P (SIMBAD/NED BibCode)
ADC_Keywords: Galaxy catalogs ; Galaxies, photometry ; Photometry, SDSS
Keywords: methods: data analysis - techniques: image processing -
techniques: photometric - galaxies: photometry - infrared: general
Abstract:
The Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) has been
conducted over a five-year period at the CFHT with the MegaCam
instrument, totaling 450 nights of observations. The Wide Synoptic
Survey is one component of the CFHTLS, covering 155 square degrees in
four patches of 23 to 65 square degrees through the whole MegaCam
filter set (u*, g', r', i', z') down to i'_{AB} = 24.5.
With the motivation of searching for high-redshift quasars at
redshifts above 6.5, we extend the multi-wavelength CFHTLS-Wide data
in the Y-band down to magnitudes of ∼ 22.5 for point sources
(5σ).
We observed the four CFHTLS-Wide fields (except one quarter of the W3
field) in the Y-band with the WIRCam instrument (Wide-field InfraRed
Camera) at the CFHT. Each field was visited twice, at least three
weeks apart. Each visit consisted of two dithered exposures. The
images are reduced with the Elixir software used for the CFHTLS and
modified to account for the properties of near-InfraRed (IR) data. Two
series of image stacks are subsequently produced: four-image stacks
for each WIRCam pointing, and one-square- degree tiles matched to the
format of the CFHTLS data release. Photometric calibration is
performed on stars by fitting stellar spectra to their CFHTLS
photometric data and extrapolating their Y-band magnitudes.
After corrections accounting for correlated noise, we measure a
limiting magnitude of Y_{AB}~=22.4 for point sources (5σ) in an
aperture diameter of 0.93 arcsecs, over 130 square degrees. We produce
a multi-wavelength catalogue combining the CFHTLS-Wide optical data
with our CFHQSIR (Canada-France High-z quasar survey in the
near-InfraRed) Y-band data. We derive the Y-band number counts and
compare them to the Vista Deep Extragalactic Observations survey
(VIDEO). We find that the addition of the CFHQSIR Y-band data to the
CFHTLS optical data increases the accuracy of photometric redshifts
and reduces the outlier rate from 13.8% to 8.8% in the redshift range
1.05≲z≲1.2. The images and the catalogue for 8.6 million sources
down to [(z'≥23.5) {lor} (Y≥23.0)] are released and available at the
following URL: http://apps.canfar.net/storage/list/cjw/cfhqsir
Description:
We generate a CFHTLS-matched catalogue of CFHQSIR objects. We use the
seventh and final release (T0007) of the CFHTLS produced by Terapix.
These catalogues are produced in each u*-, g'-, r'-, i'- and z'-band
from a g-r-i combined "chi2" detection image for each
one-square-degree CFHTLS tile. We similarly produce the Y-band matched
catalogue by using these gri-chi2 detection images and the same
SExtractor configuration parameters used for the CFHTLS catalogues. We
match this catalogue of objects covered by CFHQSIR with the CFHTLS
catalogues and produce a final photometric catalogue in the u*-, g'-,
r'-, i'-, z'- and Y-bands.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
cfhqsir.dat 646 8608680 CFHQSIR catalogue (W1, W2, W3 and W4 fields)
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See also:
II/317 : The CFHTLS Survey (T0007 release) (Hudelot+ 2012)
hpps.canfar.net/storage/list/cjw/cfhqsir : CANFAR home page
Byte-by-byte Description of file: cfhqsir.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Tile CFHTLS T0007 tile (tile) (5)
18- 27 E10.6 deg RAdeg Right ascension (J2000.0) (RAJ2000)
29- 38 E10.6 deg DEdeg Declination (J2000.0) (DECJ2000)
40- 47 F8.4 mag umag ?=-99 CFHTLS u total magnitude (AB)
(TOTAL= ISO + delta_mag) (umag) (1)
49- 56 E8.4 mag e_umag ?=-99 rms uncertainty on umag (err_umag)
58- 65 F8.4 mag gmag ?=-99 CFHTLS g total magnitude (AB)
(TOTAL= ISO + delta_mag) (gmag) (1)
67- 74 F8.4 mag e_gmag ?=-99 rms uncertainty on gmag (err_gmag)
76- 83 F8.4 mag rmag ?=-99 CFHTLS r total magnitude (AB)
(TOTAL= ISO + delta_mag) (rmag) (1)
85- 92 F8.4 mag e_rmag ?=-99 rms uncertainty on rmag (err_rmag)
94-101 F8.4 mag imag ?=-99 CFHTLS i total magnitude (AB)
(TOTAL= ISO + delta_mag) (imag) (1)
103-110 F8.4 mag e_imag ?=-99 rms uncertainty on imag (err_imag)
112-119 F8.4 mag ymag ?=-99 CFHTLS y total magnitude (AB)
(TOTAL= ISO + delta_mag) (zmag) (1) (6)
121-128 E8.4 mag e_ymag ?=-99 rms uncertainty on zmag (err_zmag)
130-137 F8.4 mag zmag ?=-99 CFHTLS y total magnitude (AB)
(TOTAL= ISO + delta_mag) (zmag) (1)
139-146 E8.4 mag e_zmag ?=-99 rms uncertainty on zmag (err_zmag)
148-155 F8.4 mag YWmag ?=-99 WIRCam Y total magnitude (AB)
(TOTAL= ISO + delta_mag) (Ywirmag) (2)
157-164 E8.4 mag e_YWmag ?=-99 rms uncertainty on Ywirmag
(err_Ywirmag)
166-174 E9.5 mag deltamag Weighted mean rescaling factor
(from ISO to AUTO) (delta_mag)
176-183 F8.4 mag umagISO ?=-99 CFHTLS u isophotal magnitude (AB)
(MAGISOu) (1)
185-192 E8.4 mag e_umagISO ?=-99 rms uncertainty on MAGISOu
(MAGERRISOu)
194-201 F8.4 mag gmagISO ?=-99 CFHTLS g isophotal magnitude (AB)
(MAGISOg) (1)
203-210 F8.4 mag e_gmagISO ?=-99 rms uncertainty on MAGISOg
(MAGERRISOg)
212-219 F8.4 mag rmagISO ?=-99 CFHTLS r isophotal magnitude (AB)
(MAGISOr) (1)
221-228 F8.4 mag e_rmagISO ?=-99 rms uncertainty on MAGISOr
(MAGERRISOr)
230-237 F8.4 mag imagISO ?=-99 CFHTLS i isophotal magnitude (AB)
(MAGISOi) (1)
239-246 F8.4 mag e_imagISO ?=-99 rms uncertainty on MAGISOi
(MAGERRISOi)
248-255 F8.4 mag ymagISO ?=-99 CFHTLS y isophotal magnitude (AB)
(MAGISOy) (1) (6)
257-264 E8.4 mag e_ymagISO ?=-99 rms uncertainty on MAGISOy
(MAGERRISOy)
266-273 F8.4 mag zmagISO ?=-99 CFHTLS z isophotal magnitude (AB)
(MAGISOz) (1)
275-282 E8.4 mag e_zmagISO ?=-99 rms uncertainty on MAGISOz (AB)
(MAGERRISOz)
284-291 F8.4 mag umagAUTO ?=-99 CFHTLS u Kron-like elliptical
aperture magnitude (AB) (MAGAUTOu) (1)
293-300 E8.4 mag e_umagAUTO ?=-99 rms uncertainty on MAGAUTOu
(MAGERRAUTOu)
302-309 F8.4 mag gmagAUTO ?=-99 CFHTLS g Kron-like elliptical
aperture magnitude (AB) (MAGAUTOg) (1)
311-318 E8.4 mag e_gmagAUTO ?=-99 rms uncertainty on MAGAUTOg
(MAGERRAUTOg)
320-327 F8.4 mag rmagAUTO ?=-99 CFHTLS r Kron-like elliptical
aperture magnitude (AB) (MAGAUTOr) (1)
329-336 E8.4 mag e_rmagAUTO ?=-99 rms uncertainty on MAGAUTOr
(MAGERRAUTOr)
338-345 F8.4 mag imagAUTO ?=-99 CFHTLS i Kron-like elliptical
aperture magnitude (AB) (MAGAUTOi) (1)
347-354 E8.4 mag e_imagAUTO ?=-99 rms uncertainty on MAGAUTOi
(MAGERRAUTOi)
356-363 F8.4 mag ymagAUTO ?=-99 CFHTLS y Kron-like elliptical
aperture magnitude (AB) (MAGAUTOy) (1)
365-372 E8.4 mag e_ymagAUTO ?=-99 rms uncertainty on MAGAUTOy
(MAGERRAUTOy) (6)
374-381 F8.4 mag zmagAUTO ?=-99 CFHTLS z Kron-like elliptical
aperture magnitude (AB) (MAGAUTOz) (1)
383-390 E8.4 mag e_zmagAUTO ?=-99 rms uncertainty on MAGAUTOz
(MAGERRAUTOz)
392-399 F8.4 mag umagAPER ?=-99 CFHTLS u circular aperture
magnitude (AB) (MAGAPERu) (1) (3)
401-408 E8.4 mag e_umagAPER ?=-99 rms uncertainty on MAGAPERu
(MAGERRAPERu)
410-417 F8.4 mag gmagAPER ?=-99 CFHTLS g circular aperture
magnitude (AB) (MAGAPERg) (1) (3)
419-426 E8.4 mag e_gmagAPER ?=-99 rms uncertainty on MAGAPERg
(MAGERRAPERg)
428-435 F8.4 mag rmagAPER ?=-99 CFHTLS r circular aperture
magnitude (AB) (MAGAPERr) (1) (3)
437-444 E8.4 mag e_rmagAPER ?=-99 rms uncertainty on MAGAPERr
(MAGERRAPERr)
446-453 F8.4 mag imagAPER ?=-99 CFHTLS i circular aperture
magnitude (AB) (MAGAPERi) (1) (3)
455-462 E8.4 mag e_imagAPER ?=-99 rms uncertainty on MAGAPERi
(MAGERRAPERi)
464-471 F8.4 mag ymagAPER ?=-99 CFHTLS y circular aperture
magnitude (AB) (MAGAPERy) (1) (3)
473-480 E8.4 mag e_ymagAPER ?=-99 rms uncertainty on MAGAPERy
(MAGERRAPERy)
482-489 F8.4 mag zmagAPER ?=-99 CFHTLS z circular aperture
magnitude (AB) (MAGAPERz) (1) (3)
491-498 E8.4 mag e_zmagAPER ?=-99 rms uncertainty on MAGAPERz
(MAGERRAPERz)
500-504 F5.3 mag E(B-V) CFHTLS E(B-V) extinction (EB_V) (4)
506-513 F8.4 mag YWmagISO ?=-99 WIRCam Y isophotal magnitude (AB)
(MAGISOYwir) (2)
515-522 E8.4 mag e_YWmagISO ?=-99 rms uncertainty on MAGAPERz
(MAGERRISOYwir)
524-531 F8.4 mag YWmagAPER ?=-99 WIRCam Y isophotal magnitude (AB)
(MAGAPERYwir) (2)
533-540 E8.4 mag e_YWmagAPER ?=-99 WIRCam Y circular aperture
magnitude (MAGERRAPERYwir)
542-549 F8.4 mag YWmagAUTO ?=-99 WIRCam Y Kron-like elliptical
aperture magnitude (AB)
(MAGAUTOYwir) (2)
551-558 E8.4 mag e_YWmagAUTO ?=-99 rms uncertainty on MAGAUTOYwir
(MAGERRAUTOYwir)
560-565 I6 pix+2 AreaY Isophotal area above analysis threshold
(ISOAREAIMAGEYwir) (2)
567-572 I6 pix+2 AreaFY Isophotal area (filtered) above analysis
threshold (ISOAREAFIMAGEYwir) (2)
574-581 F8.2 pix Xpos Object position along the x-axis
(XIMAGEYwir) (2)
583-590 F8.2 pix Ypos Object position along the y-axis
(YIMAGEYwir) (2)
592-603 E12.10 deg AaxisY Profile RMS along major axis
(AWORLDYwir) (2)
605-616 E12.10 deg BaxisY ? Profile RMS along minor axis
(BWORLDYwir) (2)
618-622 F5.1 deg thetaY Position angle (THETAWORLDYwir) (2)
624-629 F6.3 mag/arcsec+2 muMaxY Peak Surface brightness above background
(MUMAXYwir)
631-633 I3 --- FlagsY Extraction flags (FLAGS_Ywir)
635-641 F7.2 pix FWHMImgY FWHM assuming a gaussian core
(FWHMIMAGEYwir) (2)
643-646 F4.2 --- ClassStarY Star/Galaxy classifier output
(CLASSSTARYwir) (2) (7)
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Note (1): All magnitudes are given in th AB system.
Note (2): The subscript "Ywir" refers to measurements performed on the
WIRCam Y-band images.
Note (3): All aperture magnitude (MAG_APE) are given for an aperture
of 10 pixels diameter.
Note (4): E(B-V) extinction from Schlegelet al. (1998ApJ...500..525S 1998ApJ...500..525S)
Note (5): Due to a miss-matchingbetween he CFHTLS catalogues,
two CFHTLS tiles are missing in the W1 field,
W1_022929-070000 and W1_023319-07000.
Note (6): the subscript "y" in the label of the magnitudes
is the Terapix designation for the emplacement MegaCam
i-band filter, also known as i2 at CFHT. Not to be
confused with the subscript "Ywir" which refers to
the WIRCam Y-band at CFHT.
Note (7): Star/Galaxy flag as follows:
0 = extended / galaxy / non-star
1 = point-like source / star
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Acknowledgements:
Sarah Pipien, sarah.pipien(at)lam.fr
(End) Sarah Pipien [LAM, France], Patricia Vannier [CDS] 19-Apr-2018