Subject: Minutes of XID optical status meeting, 1-12-03

From: Jonathan Tedds <[email-masked]>
Date: Tue, 9 Dec 2003 18:06:42 +0000 (GMT)

Minutes of XID optical status meeting, 1-12-03, IoA Cambridge
=============================================================

1. Technical Issues re Colours
------------------------------

   - Analysis of 30 INT/1XMM AXIS fields (WMY/RGM)
	- aim to produce Green et al type Champ paper
	- g-r vs r-i colour plot for zeropoint < 0.03

   - zeropoint of WFC v.stable week-to-week BUT influenced nightly
     by transparency due to dust, aerosol
	- can be different to value assumed in processing for given field
	=> large scatter in colour distribution
		- checked for stars only and also true
		- scatter reduced if gal b accounted for

   	- best to avoid high-z standards as much greater probability of
	  being affected by freak changes in extinction etc

	- can determine colour to +/- 0.1 currently?
		- half of AXIS fields ok, half not ok
		- WM has script to correct thresholds using empirical
		  correction
		- NOTE: practical problem in choosing which *combination*
			of existing exposures per field to select in
			assessment of quality?? (09/12 WMY)
				- I suggest trying *all* combinations
				  where significant doubt but time penalty
		- suggest assigning public error of 0.5 mags if colour
		  unclear
		- expectation that colour errors will be < 0.1 where known
		- Q. can we get apparent mag errors < 0.5 ?

		=> need a photometric night + std's either side of each
		   target field
			- RGM suggests M.Irwin's GP survey time?
			- MGW suggests Director's time?

		*** ACTION - RGM/WMY to write short summary of current
                             status re colours
			   	- to feed into draft paper on INT/WFC
				  observations of 30 AXIS fields

   - Astrometric calibration
		- Champ uses GSC2
		- INT WFS uses APM (high lat)
		-  "   "   "   USNO (low lat)

2. Priorities for Jan 04 INT run
--------------------------------

   - Actions each INT night
	- if photometric - carry out sequence of calibration obsns
	- where calibration short exposure needed, ONE band only req'd
	- minimum 6 standard stars at low-z
	- repeat at least one band for each standard as check
	- 3 standards @ higher airmass, z~1.7 ?
		-> *** RGM TO REVIEW < Jan04 run ***
	- use of WMY observing scripts
	- galactic fields (contact CM)
        ***ACTION - assess fields re poss clusters => need z band (JAT)

3. XID-DB data quality & data ingestion
---------------------------------------

   - Jan 04 run
	- DB updated to rev 0722 including:
		- SOC summary data (ascii file)
		- XID band summary image products ingested from LU
		- DSS opt finder charts generated in DB
		- loaded all PI=yes and public=yes products
		*** ACTION - identify additional data required incl
			     new obsns > 0722 + non-public if necessary?
 	- SRR away from Jan 13 -> end of run

4. ESA/Public XID data interface issues
---------------------------------------
   - simple ESA interface needed
	- XSA release
		- we give files + look-up table
			- images only?
			- object cats?
		- if XSA, Vilspa development effort needed

   - internal XID
	- which web server?
		- WFC most extensive
		- WFI only ~1/5 of size
	- complex interface from LU/1XMM needed

   - have ~1 year to decide (2XMM timescale)?

5. XID processing priorities
----------------------------

   - WFC status (WMY)
	- all WFC data processed
		- still to extract catalogue from Jan 02 stacked images
		- check if all short exposures on same nights

   - WFI status
	- should be deeper than WFC in principle
	- 12 WFI large data tapes
		- diskspace problem
		- CASU pipeline v.busy
		- needs more human intervention
		- process single WFI set in CASU pipeline for assessment?
			- RGM explains practical/time problem for WMY
	- ESO public data is processed by ESO but how well (RGM)?
	- agree lower priority than resolving outstanding WFC issues (all)

6. AOB
------

   - 2dF data analysis (JAT)
	- JAT/MJP have performed Oct03 observations (4/6 good nights)
		- 2700 spectra expected with ~50% IDs in good data?
		- includes LSS fields (2x2dF pointings)
		- MJP to lead final reduction of data by end Dec
			- all data provisionally reduced
		- JAT to lead first ID of sample
			- Santander XID GUI successfully implemented at LU
  			- MJP/Santander to double-check later

   - Future PATT issues
	- Sloan release 40% of survey by Easter 04
		- ~10% of sky (20% of high lat sky)
	- WFCAM starting straight into survey
		- no PATT time
		- 4 pointings/XMM fld but only 1/4 data useful
		- earliest by next Sep
		- write proposal in next 9 mths
		- bias to south of dec +20deg + check against large
		  area survey
		- pilot with 2dF adjacent pairs?
		- focus on opt+IR, not new IDs in IR only

   - WFC ID rate > 80% ?

   - Next meeting
	- Feb 04

Jonathan

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Dr Jonathan Tedds,                          Tel: +44 (0)116 252 3502
XMM-Newton Survey Science Centre (XID),     Fax: +44 (0)116 252 3311
Department of Physics and Astronomy,
University of Leicester,                    Email: [email-masked]
Leicester LE1 7RH, UK           http://xmmssc-www.star.le.ac.uk/~jat
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