IPAC 2MASS Working Group Meeting #99 Minutes

IPAC 2MASS Working Group Meeting #99 Minutes 7/30/96

Attendees: R. Beck, T. Chester, R. Cutri, T. Evans, J. Fowler, L. Fullmer, G. Kopan, B. Light, J. White


  1. Subsystem Interfaces with EXEC/PCP
  3. CONMAN Status
  4. R1 Cutoff Magnitudes
  5. R1/R2 Position Correlation in MSX Field
  6. Expected Number of Sources
  7. Asteroid and Optical Associations


  1. Subsystem Interfaces with EXEC/PCP -- The previous meeting included discussion of J. White's recommended guidelines for consistency between EXEC/PCP and the other subsystems. The CogEs were requested to review these guidelines and design to them unless negative effects were discovered. Most of the subsystems are apparently in good shape already on this score, and several others have been discussed in splinter sessions. The guidelines as defined by J. White are now considered to be in effect.

  2. PIXPHOT & BANDMERGE Runs -- G. Kopan reported that PIXPHOT has now executed in a simulated 2MAPPS environment. While analysis is just beginning, the execution appears to be correct. The throughput time was within 50% of the FDD guideline. Some additional speedup may be possible to reduce the excess, which is caused by processing tasks that have been added since the FDD guidelines were set up. The greater capacity of the latest 2MAPPS hardware configuration should absorb any residual excess.

    As part of this exercise, PROPHOT produced its first output source list. J. Fowler reported that BANDMERGE has also produced its first output source file. The latter was based on subsystem simulation test input, not protocam data; the special test bed is needed so that all types of confusion can be precisely set up and tested. R. Cutri reported that K. Lester's protocam data conversion program was just becoming capable of generating protocam based input for BANDMERGE to use for testing. This will be used once all code branches have been exercised via subsystem simulation test data; the current test set only verifies the mainline processing, i.e., input, band-merging, position refinement, and output. All confusion processing code is in place but has not yet been tested. Statistical processing is not yet installed. Large test sets will be generated later for timing purposes.

  3. CONMAN Status -- L. Fullmer reported that design of CONMAN is underway. Some methods have been developed for doing the scan-to-scan confirmation in a more optimal way than described in the FDD.

  4. R1 Cutoff Magnitudes -- Data generated by PIXCAL/DFLAT/FREXAS have been used by T. Evans in MAPCOR development. She reported that some R1 magnitudes appear peculiar in that they are too faint to be real (e.g., 16), and requested information about whether there would be a magnitude cutoff in FREXAS. G. Kopan reported that there is currently a detection threshold, but that the photometric processing can still come up with unexpectedly faint magnitudes or no magnitudes at all, and that applying magnitude cutoffs would have to be a MAPCOR job, where the correlation with R2 extractions will occur.

  5. R1/R2 Position Correlation in MSX Field -- T. Evans and R. Cutri showed a plot of R1/R2 position dispersions derived from the MSX field. In this particular case, the correlations were encouraging, raising hopes that confusion problems in the galactic plane and other high density regions may not be as bad as expected. It should be noted that H. McCallon has found the R1/R2 position offsets to be variable, however, so the good correlation may not persist over multiple scans. The excellent correlation within the data set studied was nevertheless considered a promising sign.

  6. Expected Number of Sources -- R. Cutri reported that he had recalculated the number of point sources expected to be extracted in the survey and obtained a higher value than the previous one, about 540 million instead of 300 million. The value applies to J band, but the total number of band-merged point sources should be close to this.

  7. Asteroid and Optical Associations -- R. Cutri reported that M. Sykes is developing software that will take the four corner definition of a scan and produce a list of known asteroids contained in the scan area (with some margin) at the mid-scan time. The current FDD shows this process taking place inside the PCP scan processing, but it will probably be moved outside; all scans would be processed in a single execution prior to DBMAN, which would then do the processing to associate these "catalog" objects with 2MASS point sources. This would eliminate the option of GALWORKS employing the asteroid information, but the usefulness of this has not been established anyway, and the requirements on GALWORKS have recently been modified to reduce its avoidance of areas expected to yield difficulties for extended source processing.

    This raised the question of whether the optical catalog association processing would be done in DBMAN or in POSPTS, or whether POSPTS might produce a file for use by DBMAN. The current plan is to include optical association columns in the point source file generated by POSPTS, eliminating the need for such processing in DBMAN.