Summary:
This page describes the update to the F22I wide-field catalog. |
Why is this necesary?
The original F22I catalog was missing some data near the centre of the field. When the original catalog was being produced, it would have been impossible to reduce the missing data correctly in a timely manner. Since the F22I catalog was needed shortly for a VIMOS commissioning run, it was decided to leave out the data for the time being and add it afterwards. The data has now been reduced. Note that the data in "the hole" is of lower quality than the rest of the field. Tests show significant (~0.1 mag) differences in magnitudes measured from the new data with respect to the old. These shifts are similiar in nature to the CCD to CCD variations noted earlier (see this webpage), but greater in magnitude. As with the earlier problem, this photmetric problem has simply been ignored, pending a greater understanding of its nature. |
The patch:There are two parts to the patch. The first is the removal of the objects that are already in the VIRMOS database, the second is the addition of new objects. This is potentially a slightly messy task because of the irregular shape of the hole. The hole in effect been enlarged and made rectangular. All the entries in the VIRMOS database within the following region are affected:22:18:01.44 < RA < 22:19:10.56 00:09:24.03 < Dec < 00:39:54.702 Or in decimal degrees: 334.506 < RA < 334.794
To be removed:
/vcom/gwyn/F22Ipatch/vdb.rdxymThis file is in VIRMOS database output format and contains the following columns: ID ALPHA_J2000 DELTA_J2000 X_IMAGE Y_IMAGE MAG_AUTO_I The ID number is the VIRMOS database numbering scheme. To be added:
/vcom/gwyn/F22Ipatch/
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