I. Introduction
Analyses of the provisional Point Source Catalog (PSC) have turned up several features that require correction before the Catalog can be released. Correction involves both deleting several classes of unreliable sources (artifacts of various sorts) that were not previously identified, and adding back in rows from the Point Source Working Database that were inadvertantly omitted by the criteria for source selection for the All-Sky PSC. Failure to correct these would result in the PSC failing to satisfy the stringent Level 1 Requirements for reliability and completeness.
- Sources to be Deleted from the PSC (Status: deletions made 12/4/02)
- Single Band Sources. 68,815 southern H-only "sources" associated with hot pixels. The properties of the H-only sources to be deleted are presented here
- 922 single band, R1 sources that are unflagged detections of glint artifacts.
- Sources to be Added to the PSC (Status: additions made 12/12/02)
- High-chi-squared sources. 1,134,767 Read_2 sources (duplicate-resolved and cleaned of southern hot pixel, H-only sources) with chi-squared values >10 in all three bands. These are predominantly close double or multiple stars and moderately bright galaxies.
- Partially saturated R1 sources. 774 sources that are saturated in four or more R1 frames in all three bands.
- 44 sources that have N and M < 3.
- List of cntr values for 818 R1 sources to be added
II. Procedure for Deleting Sources
Deleting rows from the provisional PSC database table is relatively low-risk and straightforward. The steps necessary to modify the PSC and prepare it for release are:
- Identify cntr values of rows to be deleted
- Single-band artifacts (Cutri)
- R1 glint artifacts (Kopan)
- Delete rows from PSC table (Chiu)
- Validate deletion (Chiu)
III. Procedure for Adding Sources
By agreement, sources to be added will only be selected from scans in the release. The sources to be added will satisfy the edge-distant requirements for the source selection (dist_edge_ew > 10 AND dist_edge_ns > 10). No source will be added that already has an apparation within 2" of its location in the PSC. The pre-release steps for adding these sources are:
- Identify rows from WDB to be added
- High chi-squared R2 sources (Stiening)
- Partially saturated R1 sources (Kopan)
- Low N and M R1 sources (Kopan)
- Generate value-added (FPG) columns for the new sources
- designation (Stiening)
- ph_qual ('E' for all detected bands) (Stiening)
- ?_cmsig (Stiening)
- ?_msigcom (Stiening)
- julian date (Stiening)
- coadd & coadd_key (Stiening)
- use_src/dup_src (i.e. duplicate resolution - Wheelock)
- Missed Tycho star info (TBD)
- gal_contam (Nelson)
- mp_flg (Nelson)
- astrometric uncertainties (McCallon)
- ext_key resolution (Evans)
- Resolve internal duplicates in cu_psc2 table (Wheelock)
- Combine value-added rows into cu_psc2 table (Chiu)
- Merge cu_psc2 table with Working Database values for sources (C hiu)
- Normal WDB (tmass@pt_src_01) for most sources
- WDB for recalibration of 970615n and 970623n sources (tmassp@pt_src_01) takes precedence over above
- Do any final filtering of sources to be added
- Concatenate merged list of sources to be added with current PSC to construct fp_psc2 (Chiu)
- Update XSC pts_key values for any new PSC sources that have non-null values of ext_key (Evans)
IV. Procedure for Both
Once the sources are deleted from the PSC, and the new sources are concatenated to the PSC, then following pre-release steps are necessary:
- Re-index and rebuild stats for new PSC table (Chiu)
- Build new .xpf files for the new PSC table (Monkewitz)
- Modify DD for PSC to hide prox, pxpa, pxcntr fields ( Evans)
- Point GATOR to the new PSC table (Zhang)
- Validate (all)
V. Post-Release Steps
By agreement, production of the DVD will follow the on-line release. The on-line PSC release will initially be made without the prox, pxpa, pxcntr values. They will be added to the on-line version after new values are computed.
- Download ascii PSC table and send to UMASS
- Re-evaluate prox, pxpa, pxcntr for PSC entries
- Update prox, pxpa, pxcntr columns in on-line PSC
- Generate PSC DVD masters
Last Updated: 13 December 2002
R. Cutri (IPAC)