From: rse [rse@astro.caltech.edu] Sent: Wednesday, October 12, 2005 9:34 AM To: Roberto Abraham; Jarle Brinchmann; C. Steidel; Richard Bower; Crystal Martin; Elizabeth Barton; Mark Dickinson Cc: Keith Taylor; Richard Dekany Subject: IRMOS memo #2 Hello everyone: This email provides: - an update on recent work on the IRMOS science case and the outcome of the discussions held at TMT week - a description of what our science team must complete by mid- November in order to complete the OCCD - an update on design issues and the various trades remaining Please read right to the end..thanks! There are suggestions actions which we should try to close in the next two weeks so we can submit our final OCCD by Nov 13. Richard 1. Web page ------------------ First a reminder that to keep up to date you should please consult our team web page: http://www.astro.caltech.edu/observatories/oir/irmos/ which contains all the relevant information, reports and documentation including the Aspen presentations, that of our rival Florida team and more. Let me know if there's anything you can't find. 2. Science progress ------------------------ Our draft OCCD is quite a bit out of date compared to both the Aspen presentation and our actual discussions. The OCCD submitted on 9/13 was at best a placeholder. It's simply more fun to work on the science than update these documents. Anyway, the following is a summary of where the 3 main cases we investigated so far has gotten to, plus some actions for those named to consider. The prime program: resolved dynamics of z>2 galaxies (Jarle/Bob) ------------------------------------------------------------------------ ----------------- Since memo #1, we have thoroughly explored the 2 arcmin SLGLAO but not really begun the 5 arcmin MOAO studies. In part this is because we wanted to explore (and push) a low-risk first light capability. This was the message sold to the project at Aspen. Although our documentation on this is behind schedule, and we need to think a little more about presenting the best deliverable to sell how we can distinguish various velocity fields (rotating, infalling, chaotic) my feeling is that we have done enough preliminary work on this aspect for us to complete/update the OCCD. What is now needed in this area is for us to turn to the 5 arcmin MOAO capability. Very recently, we put on the web page a series of MOAO psfs received from Don Gavel (LLNL) and these should now be run through Jarle's simulations. The key questions here are (i) what additional fidelity do we get from MOAO c.f. SL-GLAO in the various situations, (ii) what are the principal merits of the wider field for a fixed 16 IFUs? Obviously we can be more selective but is this advantageous? There seems some confusion within the team on the surface density of suitable targets. Suggested actions: RSE - update OCCD to point of Aspen meeting Jarle/Bob - reconsider best simple diagnostic defining state of velocity field Jarle/Bob - continue MOAO simulations and send RSE figures Contiguous field mapping of emission line sources (Betsy/Crystal) ------------------------------------------------------------------------ ---------------- Again, this area is fairly mature although all of the key diagrams came in just before the Aspen meeting and so are not in the draft OCCD. These include the likely surface density of emitters at our flux limit, the predicted sizes of Ly alpha emitters plus the idea of surveying around known luminous high z SF galaxies to figure out the topology of the Stromgren spheres. Although some have worried the contiguous field of TiPi is quite modest (6 arcsec on a side), the ability to address key topics of reionization physics is a major selling point, I think. I am wondering how we can enlarge upon the science case of emission line mapping. TiPi distinguishes itself from the U Florida design in being able to target blank areas in this mapping mode. The contiguous field is unfortunately too small for mapping cluster lenses as Richard Bower had suggested, and mosaicing will look too much of a kluge, I fear , but maybe surveying H\alpha emission from z>2 Lya blobs is an interesting angle. I would like Chuck Steidel and Richard Bower to think about this. Do we have an advantage over IRIS? In summary, we need to (a) enlarge the science case for blind field emission line mapping, (b) emphasize the advantage we have over IRIS for survey-like applications. Suggested actions Crystal/Betsy - consider further first light applications/figures and improve OCCD RGB/Chuck - expand the emission line mapping ideas to lower z Absorption line stellar dynamics in 12' in good atmospheric conditions. - Maximum IFU size: 1.5 arcsec x 1.5 arcsec e) I think we're sticking with a square format for now for simplicities sake. Changing to a rectangular format down the track is not excluded. - IFU sampling: 50 mas f) We will be exploring ways to increase this to 70 mas (say) in the future, but it will be painful. ------------------------------------------------------------------------ ------------------------ Richard Ellis Direct line: +1-626-395-2598 Steele Professor Secretary: +1-626-395-4970 105-24 Astronomy FAX: +1-626-568-9352 Caltech, Pasadena Mobile/cell: +1-626-676-5530 (SMS/MMS) CA 91125 USA Mobile text: 6266765530@tmomail.net e-mail:rse@astro.caltech.edu URL: http://www.astro.caltech.edu/~rse ------------------------------------------------------------------------ ------------------------