From: Ariel Goobar (ariel@physto.se)
Date: Tue Apr 09 2002 - 08:31:37 PDT
Dear Chris,
w.r.t the issue of trying out how FORS2 works there is
another possibility worth considering. Assuming we get Subaru
candidates in the next hours we may want to start with a shorter
exposure (<1 hour) of a host galaxy for a case where there is a
good candidate on top of a visible galaxy. If the galaxy redshift
is in the interesting range we could go for the SN the next night.
By then we would also know the performance of the instrument.
Cheers,
Ariel
On Tue, 9 Apr 2002 clidman@eso.org wrote:
> Dear Ariel,
> At I=24.5, FORS2 should deliver a S/N ratio of approximately 2 per
> pixel (3.28 Angstroms) or 4 per resolution element (4 pixels with the
> one arc second slit) in 3 hours with the 300I grism. There is a second grism, 200I,
> with lower resolution but increased efficiency. The new CCD is meant to have less
> fringing, so the 200I may be better, but without data, it is difficult to judge.
>
> Although our main aim is to observe supernovae with z > 0.85, we may want to
> consider observing one relatively nearby supernovae (z<0.5) to make sure
> everything is working fine. We will be one of the first users of FORS2 with the new
> CCD.
>
> Gaston and I will plan our schedule in the following way. I will stay up until
> the observations have started and Gaston will come early in the morning to
> do the data reduction and post the results on the web.
>
> Contact Information
> ===============
>
> Gaston and I are sharing an office in Santiago. The number is (++56) 2 463 3106.
>
> Our results will be posted at the URL http://www.sc.eso.org/~clidman/
>
> Cheers, Chris.
>
> Ariel Goobar wrote:
>
> > Dear Chris & Gaston,
> > (CC: Saul)
> >
> > as you know, we had a short teleconference about the immediate run.
> > One of the things that were briefly touched upon is what fraction of
> > the FORS2 time we should spend in April vs May. We argued that we
> > probably want to bank >10 hs for May, especially for the early
> > half nights (May 4-6), as then we should have both Subaru and CFHT
> > candidates and still 5 mights to go before the first Keck night.
> >
> > As the first priority for the april run is 1 SN @ z>1 and 2 @ z~0.85
> > we are really looking at candidates with I>23.5. In fact, it is
> > only at I>24 where we have the largest probability of having
> > a z>1 candidate. That, in turns means, that cannot do more
> > than 3 candidates this week without exceeding our budget (unless
> > seeing is superb, of ocurse).
> >
> > Maybe you could elaborate a bit more on the table that Gaston
> > started to do here about the minimal exposure lengths needed
> > for identifying a Ia at z>0.8. I think it will become important
> > when making the last minute decission on which targets to observe
> > at Paranal.
> >
> > Cheers,
> > Ariel
> >
> > --
> > ___________________________________________________________________
> > Ariel Goobar (ariel@physto.se)
> > FYSIKUM, Stockholm University
> > Stockholm Center for Physics, Astronomy & Biotechnology
> > tel: +46 8 55378659
>
-- ___________________________________________________________________ Ariel Goobar (ariel@physto.se) FYSIKUM, Stockholm University Stockholm Center for Physics, Astronomy & Biotechnology tel: +46 8 55378659
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