Minutes from June 28/29 meeting
by Sara Seager

Attendees: Ed Churchwell, Sara Seager, Barb Whitney, Bob Benjamin, Christer Watson, Marilyn Meade, Dan Clemens, Remy Indebetouw, Mike Wolff, Brian Babler, Mark Wolfire, Tony Marston.

INTRODUCTION: Ed Churchwell

SSC ACTIVITIES: Tony Marston
IRS/Long-Low filter (20-40 microns) looks like it is delaminating, transmission is getting worse and is now 70% of what it was initially. Fringing is also a problem. The director's office recommended against a launch slip because of the IRS filter; this means the IRS filter will not be replaced.

The SIRTF launch date is July 15, 2002. Most people feel there will be a launch slip. The critical design review was passed and the timetable was agreed to, but the timetable is very tight. If there is going to be a launch slip the IRS filter will be fixed. (This means 6 months delay). No updates on launch status until October/November 2001.

Ball Testing: IRAC has come through the vibration testing fine. Problem with the shutter is believed to be understood. IRAC is fine and working within the specs. Latency is low as expected. Latency increases linearly with frame time, so the 200 second exposure frames of the GOODS team could have trouble but our two second exposure frames shouldn't have a problem. For example, some low level long term latency which takes 1000s of seconds to go away will be a problem for the GOODS team. A latency report is overdue and will be released soon.

Uplink Test. Problems have gradually been removed and it works now.

Software release. SPOT. Review of release came out this past Tuesday. Will be out in mid-July or possibly later. Trying to note the major bugs still left. S5 is the version we will be asked to use to supply AORs to the SSC. All AOR durations appear to be increased by a few percent over S4 values. This has probably been caused by changes to the slew model. A new model of telescope was input in the most recent delivery. This number is probably going to change later. IRAC expansions indicate 21 seconds (total) per position for scans of a type similar to that used by GLIMPSE. The two second time frame has been implemented in SPOT.

Overlaps with GTO targets. For those surveys that go over GTO pointed observations, those AORs will be embargoed. GLIMPSE has some overlaps with GTO observations, but the exposure times are so different that they are considered as different observations.

Observing Strategy Review will take place 9am to 1pm on Wed Sept. 5, 2001. The questions will be set in advance and we will receive a copy of them in advance. Reviews will involve members from director's office, instrument support team members, liaisons, observer support team members, a downlink member, etc.

Is SSC on track if we had launch July 2002? Things got stuck at Ball for testing because of the dewar problem. But, instrument testing has gone extremely well. The biggest concern at SSC is downlink. If the IRAC shutter is not working they will leave it open and this will cause additional need for a lot of testing. Uplink is fine, although there is a lot to be done. It is not obvious that the SSC will be able to hire the number and quality of people needed for instrument team, observer teams, etc. Problems/delays are likely to come from outside of the SSC.

BARB AND MIKE'S VISIT TO PASADENA: Barb
Barb and Mike spent two days at SSC earlier this week. The main goal of their trip was to find out about SSC software, specifically the point source extractor, the mosaicer and the band merger. These are required to be ready by launch. The point source extractor and band merger are quite far along, but the mosaicer is not as far along. We can't wait until launch to put these things into our pipeline. To try to see these programs in advance of their release, we could perhaps do beta testing for them, without asking for support, etc. We would really like to see these things by October or else we will have to develop our own, even though it is a waste of resources. It sounds like if we need to use DAOPHOT that should be sufficient.

Validation and quality control is something SSC and we are just starting to think about. The instrument team has not yet defined a set of validation rules if something is worth reobserving. The SSC will flag problems that are passed onto the users. If there is a huge problem with some data the observer support team, via the help desk, can try to get something reobserved or pass it through the pipeline (with a fix) again. The shortest possible turnaround to reobserve is 48hrs. In reality the turnaround to reobserve is more like 3 weeks.

GLIMPSE OBSERVING STRATEGY : Christer
Prelminary AORs delivered to SSC. The current model is 2xn strips for a rectangular segment each of which is observed in a 12hr downlink period. Nearly complete coverage. The problem with this model is that the charge time is 588 hr. But, this observing strategy is good, and we should still stick to the basic strategy. The major reduction in time is for s longer number of hours/down link. A six hour run has 85% efficiency where 5% is spent on the 3 minute overhead ("slew tax") for every AOR, 10% for actual observing outside of the desired area. There is a slight offset in the two IRAC fields. We can make a full set of AORs in about 2 minutes.

Ideas to reduce the total observing time.

Use longer segments: 10 degrees in longitude. This gets down to 505 h. Vary strip width. Dan Clemens suggested to look at 7xn and to use variable widths at the corners of the rectangular patch. Variable widths has been implemented. Cutting corners. Some corners aren't worth the 3minute slew tax, especially with the offset in the two fields which might put some outside of the galactic plane. Changing shape of the boundaries (e.g. where stuff overlaps)?

Jagged Edge. This is the only solution without cutting latitudes or longitudes that matches the 400 hours. Remove all extra exposures along b = +/- 1. This misses lots of area inside b=+/- 1, but can be done in 363 hours. Some suggested to make this decision with the team, and not to present the indecision to SSC, or they might decide to cut our program.

Cut out high galactic latitudes? Alternatively, we could cut longitude, but we might have to neglect specific objects like the coal sac. Time saved scales roughly linearly in time with longitude. Cutting longitude has the advantage that it might be possible to do the missing longitude ranges with GO proposals later but not to fill in jagged boundaries near B=+/- 1.

POST-PIPELINE DATA PROCESSING: Barb
See the team website for the handouts and progress update. www.astro.wisc.edu/sirtf/Team/Processing/progress-june28.html

DATABASE AND PIPELINE DEMO: Mike and Barb
See the team website for the handouts and progress update. www.astro.wisc.edu/sirtf/Team/Processing/progress-june28.html

Summary:
Excellent progress has been made so far. Barb, Marilyn, Mark, Mike, and Brian are all working on different things. The database will take SSC data and spits out a 20 sigma catalogue. There is some concern that if other groups aren't ready until launch, they might come to us for help, but we don't have the personnel to "subsidize" their programs. On the other hand, other teams aren't interested as much in point sources. Note that we will be asked about the data pipeline at the observation strategy review

IR TOOL SHED DEMO: Mark Wolfire.
See his website: http://wits.ipac.caltech.edu This looks like a very powerful tool for analysis of IR data.

SCIENCE WITH MSX AND 2MASS: Bob Benjamin
Showed us a nice 8.28 micron image of the Galactic Plane from MSX There will be a pointer to the 100 MB file on the GLIMPSE website. MSX covers what we want. 2MASS current public data only covers patchy region, but will be useful for testing photometry. Bob also discussed science in advance of SIRTF using 2MASS and MSX data. Three useful things to do in advance: resolve distance ambiguities with arecibo survey (Ed) or possibly HI; make a catalogue of star forming regions; color-mag and color-color diagram modeling.

AUTHORSHIP RULES
There were many different suggestions: author order by amount of work contributed; "builders" allowed to be on every paper; some initial papers that all team members would be on with later, more detailed papers where just the main contributors are authors. Other relevant questions: team member authorship on community papers that we have helped with GLIMPSE data; requests from the community for collaborative projects; students and postdocs. Ed will summarize the authorship order as he sees it and we can comment on it later.

SCIENCE DISCUSSION
Some concern about community using our data for science before we have time. Tony stresses that the data is public as soon as it is taken, and the community can write science papers as soon as we make our public delivery. Others said we should not have collaborations giving community access to the data any earlier than we make it publicly available. The stellar disk scale length is an example of data people will jump on.

Dan suggests to have a scientific meeting a year from now to get the community involved. Dan will look into location and funding possibilities for this.

General comments: which things can we reasonably attack first? Ed suggests that we should think about what region to we want to observe first. We need to do a lot of work trying to identify which kinds of objects have unique IRAC colors. Some discussion about taking data from other teams and running it through the pipeline. Most people thought this was a bad idea but we could legitimately propose for GO archival proposal and even get money for it.

Individual interests:

Sara: field brown dwarfs and old brown dwarfs, possibly free floating planets.

Bob: stellar disk's scale length, content and energetics of inner spiral arms. Would like to pick one type of object to characterize (e.g. a superbubble).

Barb: Statistical studies of SEDs in star forming regions. Cloud cores and modeling radial profiles and SEDs of them. Followup of interesting objects and doing detailed models of them, e.g. protostars.

Mike: UV and visible data in conjuction with SIRTF data can get something useful on largest and smallest grains (hotter from nonequilibrium heating). But getting a handle on optical properties of the grains is pushing it.

Dan: Ideas for several major topics with a few major papers in each of them. Galactic structure: molecular ring properties; searching for the Galactic bar; determining the disk scale length; tracing other basic properties of the Galaxy e.g. by OH-IR stars. Star formation regions: Galactic census; near-IR to mid-IR signatures of SF regions?; Where does star formation take place---inside the molecular ring or outside?; luminosity function, initial mass function; what triggers star formation?; spiral structure inversion to get a face-on picture. Other: quiescent dark clouds; PDRs; SEDs.

Ed: Massive star formation regions and their SEDs. A number of individual objects, e.g ultra-compact HII regions and pre-stellar cores. Stellar content of massive star formation regions; location and distribution of stars in compact clusters.

Christer: Massive SF regions and ultra compact HII regions. In particular massive SF SF census compared to low-mass SF formation census. Study of the phase preceding ultra compact HII regions. IMF: high end what it can tell us about mechanisms of massive star formation. Energetics in diffuse regions.

Mark: PDRs and massive star formation. PDR catalogue of regions. Individual objects. PDRs can be identified just with IRAC bands since they don't look like a blackbody continuum.

Tony: Several of the previous topics mentioned. Interested in Wolf Rayet stars and their environment. Many of them are found away from molecular clouds and no one has done a Galactic census of them; 200 WR stars are known in the galaxy but there are probably double that number. WR stars have uniqe IRAC colors. 2MASS can't find WR stars because wavelength coverage doesn't go far enough into the IR. Identifying WR stars will require some follow up spectroscopy, possibly on all of them.

PERSONEL PLAN: STAGE 1 AND STAGE 2

Pipeline Development: Brian, Marilyn, Barb, Mike, Mark, Remy
Mosaicing: Mark, Remy
Validation: Remy
Source extraction software and testing-group
Catalogs: Mike, Barb, Mark

Observational Strategy: Christer, Chip, Remy
Survey Tracking, On-the-fly AOR changes

IR Tools: Mark

Scientific Development
*CMD modeling
*IO Algorithms
*CC Plots: Bob, Ed, everybody
*Ancillary Data
*Brown Dwarfs: Sara, Mike
*Galactic Structure Issues: BU, Bob, Ed

Early Release (something that is pretty and that highlights the characgteristics of SIRTF wrt 2MASS and MSX

BUDGET DISCUSSION

$100,000 extra from SSC. Ed will wait until hearing about launch delays before deciding what to do with it. It will not be availabe until after Oct. in any case.

Travel and publication charges for the team will be in the Wisconsin budget.

Discussion of which area to look at first. Ed will provide a list of potential UC HII regions that are likely hidden to 2MASS but likely visible to SIRTF/IRAC in the range l=40-60. We can discuss this at a telecon later.

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