GOODS based Reduction

Catalogued objects from the GOODS Chandra Deep Field South z band catalogue h_goods_sz_r1.0z_cat.txt over the region of the UDF HRC drizzled fields were extracted and compared with the HRC F555W catalogues. This has two purposes: one to allow extraction of spectra where the direct object falls outside the HRC field; secondly to select red objects which would not appear in the v (F555W) filter. These objects would be classified as v band dropouts (though they might also be i band dropouts). Given the red sensitivity of the G800L grism, spectra of red objects would be missed if only the F555W based catalogue was used to flag spectra for extraction.

The agreement between the coordinates from the GOODS and HRC based catalogues was assessed, based on the offsets of about 25 objects clearly in common. Small offsets of maximum 21mas (0.8HRC pixels) were applied to the HRC based catalogue. After applying the correction the common set of object coordinates agreed to within +/-3mas. This catalogue was then used as the basis to extract the spectra of all the HRC F555W objects and the extra GOODS objects. The spectra and the direct object details of the HRC F555W catalogued objects are presented for epoch-1 (objects 1-39) and epoch-2 (objects 1-70). For the extra objects only detected from the GOODS z band catalogue, either objects lying just outside the HRC UDF fields or red objects, the spectra and object details for epoch-1 (objects 101-136) and epoch-2 (objects 101-137) are given.

Correspondence between the IDs of GOODS objects in the UDF data and the IAU names in the GOODS CDFS catalogue are listed for Epoch-1 and Epoch-2.

All the objects found on the Epoch-1 HRC F555W image had corresponding images in the deeper GOODS catalogue (the F606W catalogue [h_goods_sv_r1.0z_cat.txt] was searched). However for the Epoch-2 HRC F555W image, a number of sources were not detected in the GOODS catalogues and may not be real:
#1 - Located near edge of UDF F555W field, use #136 / #137 (from GOODS)
#2 - Noise? (not seen in GOODS F606W)
#6 - Uncorrected hot pixel? (not seen in GOODS F606W)
#24 - Noise? (low S/N, not seen in GOODS F606W)
#48 - Noise? (low S/N, not seen in GOODS F606W)
#55 - Noise? (low S/N, not seen in GOODS F606W)
#58 - Noise? (low S/N, not seen in GOODS F606W)