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All CFHTLS Wide images: (mean CCD seeing)-(mean Megacam seeing) B A B A B A B A B A B A B A B A B A Mean CCD seeing contrast with respect to mean MegaCam seeing 0.06 00 01 02 03 04 05 06 07 08 0.1 0.04 B A B A B A B A B A B A B A B A B A 0.02 09 10 11 12 13 14 15 16 17 0.05 0 18 19 20 21 22 23 24 25 26 0 -0.02 A B A B A B A B A B A B A B A B A B z -0.04 g u 27 28 29 30 31 32 33 34 35 -0.05 z g u A B A B A B A B A B A B A B A B A B 0 10 20 30 CFHT MegaCam CCD reference number 0 10 20 30 CFHT MegaCam CCD reference number Figure 27: PSF variations as a function of the position on MegaCam (CCD positions) and wavelength (filters), produced by the optical distortion of the MegaPrime wide field corrector. These statistics are based on 935 u ∗ , 978 g, 1669 r, 1064 i and 1177 z-band images (the 220 y-band images have been ignored here). The variations are estimated from the comparison between the mean seeing (FWHM) averaged over the MegaCam field of view and the mean seeing averaged over a CCD field of view. The statistics are computed over the 36 CCDs composing the mosaic. The CCDs are numbered using the CEA-CFHT CCD reference number laid out on the central figure. The left panel show the difference 〈FHWM〉CCD − 〈FHWM〉MegaCam expressed in arcseconds. The horizontal axis is the CEA-CFHT CCD reference number. One can see that for the CCDs at the edges of the detector, the differences never exceed 0.065", and the highest peak-to-peak amplitude is less than 0.1". The right panel shows the seeing contrast |〈FHWM〉 CCD−〈FWHM〉MegaCam| 〈FWHM〉MegaCam . The contrast is always lower than 10% and the highest peak-to-peak contrast amplitudes are always less than 15%. Overall, the range of seeing values over the MegaCam field of view is acceptable. However, at the extreme corners of MegaCam, the seeing difference with the mean value can be as large as 0.25". Only the most extreme positions have a large PSF degradation and images that no longer meet the specifications of the surveys. We discard these regions by adding extra polygons to the T0007 .reg files that mask the edges of all stacks. The fraction of the MegaCam field discarded is less than 3%. i r i r 40
Figure 28: Completeness calculation for the W3 stack CFHTLS_W_i_142939+514231. Left panel: The blue and red lines shows the completeness for point-like and extended sources respectively. The green dots show the best fitting functions which are used to derive the completeness values. Right panel: galaxy counts derived automatically by QualityFITS from this stack. The red line shows the expectations for the MegaCam i-filter. The green line is the 80% completeness limit of extended objects. 4.3 Depth and completeness limits The depth of the survey tile is measured by the completeness limit. It is determined for each stack and each filter separately. The depth is also checked by using the galaxy counts computed after the production of each stack, as part of the QualityFITS analysis. All completeness galaxy count plots are available from the T0007 synoptic table 22 . To compute the completeness limit, we used image simulations produced by SkyMaker(Bertin, 2009). Noiseless images of point-like (stars or galaxy bulges) and disk-like (spiral galaxies) sources have been simulated by combining spheroid and disk models, using de Vaucouleur and exponential light profiles, respectively. The star and galaxy number densities of simulated sources correspond to the expectations for typical CFHTLS exposure times. Their slope and normalization are based on realistic luminosity function in a standard Λ-CDM cosmology (for galaxies), and are produced according to the transmission of the MegaCam filters. The sources are then convolved by a PSF that takes into account the pupil of the CFHT telescope (mirrors and arms) and other components of the PSF. The PSF is built by using the diffraction and the simplest aberration components of the CFHT telescope, as well as the typical atmospheric contributions that degrade long exposures. A set of simulations are produced with PSF FWHM ranging from 0.4 ′′ to 1.3 ′′ . For each stack, the simulated images with the closest PSF in FWHM size is then used to compute the final completeness. This “adaptive FWHM” method gives rise to larger dispersion in the completeness distribution compared to T0006. The T0007 completeness encompass both the exposure time and depth effect, as well as the image quality. The point source completeness is therefore more affected than the extended objects one. The completeness limit is then derived from the averaged completeness value over the central 10000×10000 MegaCam fields. The statistics are computed in each field separately and for each filter. The output is the fraction of sources detected and measured as a function of magnitude. The magnitudes at 80% and 22 http://terapix.iap.fr/cplt/T0007/table_syn_T0007.html 41
Page 1: T0007 : The Final CFHTLS Release Pa
Page 4 and 5: patches are provided. Sources from
Page 6 and 7: Contents 1 CFHTLS-T0007 Executive S
Page 8 and 9: B.1 Rescaling factors applied to de
Page 10 and 11: 33 Galaxy counts for the four Wide
Page 12 and 13: 30 Description of parameters listed
Page 14 and 15: B A B A B A B A B A B A B A B A B A
Page 16 and 17: constraints. Two series of Deep sta
Page 18 and 19: evealed minor problems (such as unu
Page 20 and 21: een preferable because of the highe
Page 22 and 23: Figure 5: Outputs of the SCAMP cali
Page 24 and 25: Figure 7: CFHTLS T0007 absolute pho
Page 26 and 27: Figure 8: Seeing FWHM distribution
Page 28 and 29: Figure 10: Aperture correction (def
Page 30 and 31: Filter u g r i z - ApCorr - ApCorr
Page 32 and 33: Figure 14: Photometric calibration
Page 34 and 35: Figure 17: Photometric calibration
Page 36 and 37: Figure 18: Matching between one L99
Page 38 and 39: • four (u, g, r , i/y, z) Wide pa
Page 40 and 41: W1 W2 N N E E W3 W4 N N E E Figure
Page 42 and 43: CFHTLS Reference center Total Total
Page 44 and 45: Each tile is centered at a well-def
Page 46 and 47: Field Parameter u ∗ g r i y z W1
Page 48 and 49: Figure 23: Distribution of exposure
Page 50 and 51: Figure 25: Distribution of the medi
Page 54 and 55: 50% completeness are given for poin
Page 56 and 57: 80% completeness limit (stars) 26.0
Page 58 and 59: 10 5 W1 W2 W3 10 5 W1 W2 W3 N gal 0
Page 60 and 61: Wide Field Magnitude range u ∗ g
Page 62 and 63: Wide Field Magnitude range u ∗ g
Page 64 and 65: paths. From the joint effort betwee
Page 66 and 67: Wide field External magnitude offse
Page 68 and 69: Wide field External rms errors with
Page 70 and 71: Figure 38: Comparison of one CFHTLS
Page 72 and 73: 4.5.2 Absolute astrometric accuracy
Page 74 and 75: 4.6 Outliers, stacks with exception
Page 76 and 77: Figure 40: Mean RA-DEC offsets betw
Page 78 and 79: Figure 42: Mean RA-DEC offsets betw
Page 80 and 81: W Cartesian CFHTLS Special filter V
Page 82 and 83: accurately reflect the integration
Page 84 and 85: Field Parameter u ∗ g r i y z D1-
Page 86 and 87: Field Parameter u ∗ g r i y z D1-
Page 88 and 89: 76 Figure 43: Comparison of the (u
Page 90 and 91: Figure 44: Estimation of the intern
Page 92 and 93: 5.4 Depth and completeness limits T
Page 94 and 95: D2 u−band (25% best−seeing imag
Page 96 and 97: log Ngal 0.5 mag −1 deg −2 5 4
Page 98 and 99: - there is one chi2 image per Wide
Page 100 and 101: File name Content Data Size Number
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File name Content Data Size Number
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6.3 Content of CFHTLS source catalo
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stacks made with the y-(i.MP9702) f
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Id Parameter Description Units Comm
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6.4 The QualityFITS input and outpu
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Figure 48: QFITS-out page of the W4
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102
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Figure 51: Upper panel: CFHTLS all-
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A CFHTLS T0007 Wide supplementary i
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Table 31 - Continued from previous
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A.2 List of images in each Wide sta
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DISTORT_GROUPS 1,1 # Polynom group
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#--------------------------- Photom
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#--------------------------- Photom
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#--------------------------- Photom
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#--------------------------- Backgr
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#--------------------------- Backgr
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#------------------------- Star/Gal
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#--------------------------- Star/G
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B.2 CFHTLS T0007 Deep configuration
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SCAMP astrometric run using interna
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SCAMP photometric run (D1,D2,D3,D4)
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B.2.2 SWarp stack configuration fil
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B.2.3 SWarp chi2-image configuratio
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B.2.4 SExtractor .ldac catalogue co
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B.2.5 SExtractor DUAL MODE .cat cat
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Acronyms & Abbreviations ASCII CADC
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References Astier, P., et al. 2006,
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