Subject: MOS_IFS study Date: Tue, 16 Feb 1999 23:32:37 GMT From: Santiago Arribas To: rfosbury@eso.org Dear Bob, It follows some news/comments/questions related to the IFS-MOS trade-off study. 1) Curves __________ I have produced some curves for estimating exposure times (& density of objects) for the HR and LR IFS-modes for a set of resolutions (100, 300, 1000, 3000) and S/N (10, 30). They depend in as much as possible on observational data, instead of asumptions on the galaxy luminosity/type, redshift, etc. Please give me a ftp address, in order I can send them to you. 2) HDF _______ In order to both, i) check the Yan et al data and ii) extend the curves for fainter magnitudes, I think it is necessary to go further with SExtractor in the HDF. I did a quick comparison between the data you sent to me and the Yan data and it is clear that 'sizes' are defined in a different manner in both cases. I do not know how difficult could be, but if it were possible to obtain half-light radii (and magnitudes) for the HDF both the comparison and the extension should be straightforward. 3) MOS _______ Are correct the following parameters for the MOS instrument ? FOV: 3' x 3' , pixel scale: 0.03"/pixel Are known the 'slit width' and the maxi.mun number of objects that can be observed at once? Is there any other relevant parameter ? I am ready to orientate my work for this trade-off study in the direction you may consider more useful. If you have any suggestion about it please let me know. All the best, Santiago Subject: Re: MOS_IFS study Date: Wed, 17 Feb 1999 11:50:36 +0200 From: Bob Fosbury Organization: ST-ECF To: Santiago Arribas Dear Santiago. You can ftp to: ftp2.hq.eso.org to cd users/rfosbury/incoming I'll put what you send on our webpage... I will try to get the HDF catalogues - either from people at STScI or from measurements here. There is also the Thompson et al. HDF-N NICMOS paper AJ 117, 17 - have you looked at that? I too am trying to find out about the MOS specifications - meanwhile, I attach a copy of the paper presented at Kona SPIE meeting by Richard Burg - it contains something about the MOS. One of the things to do which I think would be particularly useful at the moment is to look at the efficiency of the MOS in reaching galaxies at the right depth in a 3 x 3 armin field. People must have looked at this... I'm just off to Paris for the ECF annual review - but we have a raging blizzard here at the moment so??? Will be in touch next week when I can get back to this stuff.