Report from CASU ================ Data transfers -------------- These are running smoothly as usual through completion of 10A and the first few months of 10B. The raw WFCAM data archive in Cambridge is up to date, as are the transfers of all raw UKIDSS and calibration data to the ESO archive. For the current state-of-play including transfers and processing status see http://casu.ast.cam.ac.uk/surveys-projects/wfcam/data-processing/ Another one of the odd transfer hiccups surfaced after Chris Davis noticed some missing #4 data that he had taken on 29th July 2009. About 2/3 of detector#4 data had gone walkabout prior to transfer for that night. It looks like this is a very unusual occurence and not clear what the underlying cause was. JAC put the relevant data for 20090729 online for all cameras and it was retransferred and reprocessed and re-released within a few days. Cassegrain UKIRT archive ------------------------ No real change other than a few nights that had been flagged as "private" were made publically available. WFCAM processing ---------------- Semester 10A processing was completed on time and the first two months of 10B processed data have now passed their final QC checks and monthly photometry updates and have been flagged as ready to copy for WFAU. Pipeline updates ---------------- There have been no significant changes recently. User queries ------------ We also deal with a lot of queries from users who either don't understand some aspect of the processing, or who believe they have found a fault in the processing or calibration, or indeed who want to try their luck at processing the raw data themselves. [The latter we tend not to hear from again after supplying them with the raw data.] Some of these queries often involve quite a bit of detective work as in the interesting problem below noticed by the UDS team. The UDS team noticed an interesting pattern in J & K-band deep stacks prior to DR8 release. We investigated the problem, ruled out decurtaining due to the symmetry being wrong, and tracked the problem down to a less than 1 part in 10000 effect visible in individual MSB stacks, if you know what to look for. This looks like a (very minor) hardware feature whereby brightish stars in each quadrant cause a slight depression, or sometimes a slight rise, in the background level along nearby rows and/or columns. The effect is isolated in quadrants suggesting it is a readout feature. At this level it only becomes really noticeable when deep stacks are made. In the K-band, for example, the surface brightness of these stripes is between 23.5 and 24 mag/sq arcsec. Unfortunately as the effect is "attached" to the stars it does not go away on normal stacking and is probably best corrected during intermediate depth stacks (to minimise quadrant overlaps). This resulted in a delay to UDS DR8 although begs the question of why this effect was not noticed earlier. Fast-track releases ------------------- There have been various fast-track flat file release requests including: U/10A/8 Steve Warren - multiple fast access requests U/10A/K4 SangHyun Chun - dribbling U/10A/J5 Noriyuki Matsunaga - fast access + dribbling U/10A/H99 Niall Deacon - multiple fast access requests USERV1876 Sandy Leggett - multiple fast access requests U/10B/K1 Myungshin Im - fast access the dribblers tend not to "like" the spikey PSF that comes gratis with stacked interleaved microstepped data. WFCAM reprocessing ------------------ The reprocessing queue has been depleted further by completing around 2/3 of the reprocessing required for the "Cloudshine" project (U/06B/30, U/07B/6 and U/SERV/1763). The problem here originated from the "ad hoc" arrangements in place at the time to deal with offset skies. These 13 nights of data are being reprocessed, with some manual intervention in setting up the processing, such that the desired offset frames are used for sky estimation and subsequent subtraction. The feedback for the UDS J-band reprocessing for some 57 nights of 05B-07B data was positive, so the H-band reprocessing of a similar amount of data for the same period is next in the queue (and currently the last) . A modest amount of nebulosity filtering and re-cataloguing for selected GPS DR7 fields was also undertaken and re-released. Phil Lucas noticed a problem with the WFCAM calibration drifting out of spec in regions of extremely high extinction E(B-V) > ~10. This is mainly due to the extinction coefficient correction term applied to all WFCAM data. This was derived from data with 0 < E'(B-V) < 2, where E'(B-V) is the Bonifiacio et al. (2000) modified Schlegel et al. (1998) extinction. The error in the slopes (coefficients) becomes significant by E(B-V)=10 leading to a systematic offset in the calibration in the J,H,K bands. With the recent data in the Galactic Plane in the Bulge region this problem has become more apparent. We are currently investigating ways to improve the calibration in these regions (around 150 WFCAM pointings). Funding for WFCAM processing ---------------------------- As noted in the last Board report, the CASU rolling grant funding that covers WFCAM processing, reprocessing, troubleshooting, updates, user support etc.. is in place. If there are no further significant changes we will be able to continue to provide support at the current level of 1 FTE/yr for all WFCAM-related matters up to at least the end of March 2012.