4.6 Outliers, stacks with exceptions or anomalies
Several images show unusual properties with respect to the bulk sample of stacks. This is the case for the 32
y-band stacks that are expected to have slightly different (photometric) properties compared to the other 139
i-band tiles due to the slightly different bandwidth of that replacement filter after the original one broke in
2007.
The most common technical anomaly is an amplifier failure during an observing sequence. Since all CCDs have
two outputs, several images show missing data from a half or a full CCD area. Usually, each observing
sequence is done only once, so the data from the missing CCD cannot be recovered. However, since the
CCD failures are intermittent, the r-band observations which have been split into two observing
sequences normally do not experience this missing data problem. We note furthermore that many of the
pointings originally affected by this problem have been re-observed by in Director’s Discretionary
Time (images with more than one full CCD missing have been rejected during the image selection
stack.)
Problematic T0007 stacks are listed in Tables 14 and 15, with a short description. None of these problems are
critical for the scientific exploitation of the survey, but there are some half-CCD size regions of the CFHTLS
Wide where one or two filters are missing.
|
|
|
|
| | | | | | W Cartesian | CFHTLS | Special filter | VIPERS-DDT images | Comments |
Ident name | Ident name | | | | | | | | |
|
|
|
|
| | | | | | W1(-4 - 4) | 020241-104400 | y-band observations | | |
| | | y-band exp. time is 7380 s. |
W1(-3 -4) | 020631-104400 | y-band observations | | |
W1(-2 -0) | 021021-070000 | | | radial astrometric offset around 0.090" in all bands |
W1(-2 -4) | 021021-104400 | y-band observations | | |
W1(+2 -0) | 022539-070000 | | | g-band: CCD#03 missing |
W1(+2 + 1) | 022539-060400 | y-band observations | y-band | |
W1(+2 + 2) | 022539-050800 | y-band observations | u*-band | |
W1(+2 + 3) | 022539-041200 | | | u*-band and z-band: CCD#03 missing ; |
W1(-1 -4) | 021410-104400 | y-band observations | | |
W1(-0 -4) | 021800-104400 | y-band observations | | |
W1(+1 -4) | 022150-104400 | y-band observations | | |
W1(+1 -1) | 022150-075600 | y-band observations | | |
W1(+1 + 1) | 022150-060400 | y-band observations | | |
W1(+1 + 3) | 022150-041200 | | | i-band : two 1/2 CCD missing (CCD#07 and CCD#11) |
| | | | u*-band radial astrometric offset 0.084" | W1(+2 - 4) | 022539-104400 | y-band observations | | |
W1(+3 -4) | 022929-104400 | y-band observations | | |
W1(+3 -0) | 022929-070000 | | | g-band and i-band : CCD#03 missing ; |
W1(+3 + 1) | 022929-060400 | y-band observations | g-band | |
W1(+3 + 2) | 022929-050800 | y-band observations | g-band, y-band | |
W1(+3 + 3) | 022929-041200 | | | g-band and i-band : CCD#03 missing |
W1(+4 -4) | 023319-104400 | y-band observations | | |
W1(+4 -0) | 023319-070000 | | | g-band and i-band : CCD#03 missing ; u,gand i-band radial astrometric around 0.079" |
| | | | |
|
|
|
|
| |
Table 14: | CFHTLS Wide stacks with exceptions or anomalies. |
|
|
|
|
|
| | | | | | W Cartesian | CFHTLS | Special filter | VIPERS-DDT images | Comments |
Ident name | Ident name | | | | | | | | |
|
|
|
|
| | | | | | W1(+4 + 1) | 023319-060400 | | g-band | |
W1(+4 + 2) | 023319-050800 | y-band observations | g-band | |
W1(+4 + 3) | 023319-041200 | | | i-band : CCD#03 missing |
| | | | | W2(-1 + 3) | 085011-012700 | | | g-band : CCD#03 missing |
W2(+1 + 1) | 085749-031900 | y-band observations | | |
W2(+3 + 1) | 090526-031900 | | | g-band : CCD#03 missing |
W2(+3 + 2) | 090526-022300 | | | g-band : CCD#03 missing |
W2(+3 + 3) | 090526-012700 | | | g-band : CCD#03 missing |
W2(+2 + 2) | 090137-022300 | y-band observations | | |
| | | | | W3(-3 + 1) | 135846+552631 | y-band observations | | |
W3(-2 -0) | 140525+543031 | | | u*,g,r,i,z contamination: Messier 101 galaxy on the 4th (bottom right) MegaCam quadrant |
W3(-2 -1) | 140540+533431 | y-band observations | | |
W3(-2 + 1) | 140509+552631 | y-band observations | | |
W3(-2 + 3) | 140433+571831 | y-band observations | | |
W3(-1 + 3) | 141113+571831 | y-band observations | | |
| | | | y-band radial astrometric offset 0.077" |
W3(-0 -1) | 141754+533431 | | | g-band seeing anomaly: 1.045" |
W3(+3 -1) | 143615+533431 | y-band observations | | |
W3(+3 + 2) | 143728+562231 | y-band observations | | |
| | | | | W4(+1 - 1) | 221706+002300 | | | |
W4(-1 -1) | 220930+002300 | y-band observations | | |
W4(-1 + 1) | 220930+021500 | y-band observations | | |
W4(-1 + 2) | 220930+031100 | y-band observations | | |
W4(-1 + 3) | 220930+040700 | y-band observations | | |
W4(-2 + 2) | 220542+031100 | y-band observations | | |
W4(-2 + 3) | 220542+040700 | y-band observations | | |
W4(-3 + 3) | 220154+040700 | y-band observations | | |
| | | | |
|
|
|
|
| |
Table 15: | CFHTLS Wide stacks with exceptions or anomalies (cont’d). |
|