Re: Optimization of observations for the HST search

From: VAFadeyev@lbl.gov
Date: Sat Oct 18 2003 - 15:06:23 PDT

  • Next message: VAFadeyev@lbl.gov: "Re: Optimization of observations for the HST search"

    Hi Saul and Rachel,

    the questions are good. We'll need to run
    some more simulations (very doable) to answer
    them.

    As Rachel pointed out, the results are based
    on her S/N curves. Those would need to be
    extended to the "negative" times a bit to
    answer the 2nd question. The curve for z=1.5
    would need to be generated.

    Rachel, if it is easy for you to do, I think
    I would prefer to have the S/N table PER ORBIT
    on a given day of the lightcurve. That would
    remove most of the approximations in the orbit
    counts.

    I will come to work for a few hour tomorrow
    afternoon. If the tables are ready, then
    the simulations will be done. In any case
    will make a description of my scripts which
    run on top of Rob's software, so that other
    people could run it easily.

    Cheers,
    vitaliy

    ----- Original Message -----
    From: "Rachel G." <gibbo@panisse.lbl.gov>
    Date: Saturday, October 18, 2003 1:43 pm
    Subject: Re: Optimization of observations for the HST search

    >
    > Hi Saul,
    >
    > Vitaliy doesn't have all the information from me
    > that he needs to do this. I will need to produce light
    > curves (and SNR) that go to a much earlier epoch. Also,
    > if Vitaliy isn't available this weekend, I can run these
    > tests. We have scripts set up now to do the SNR calculations
    > and fit lightcurves relatively quickly. B
    >
    > However, regarding your question #3, last night we
    > did begin to look at at how well we'd do with a 4-point
    > light curve. We ran a couple of examples (it was getting
    > late), at z=1.2,1.3. The runs look like this:
    >
    > z #orbs day_observer fit_stretch fit_max
    > --- ----- ------------ ------------ -----------
    > 1.3 4 -3 7 17 37 0.998+-0.134 24.19+-0.06
    > 1.4 6 -3 7 17 37 1.007+-0.157 24.40+-0.06
    >
    > So the errors on streatch are expected to increase
    > about 30% over the numbers in Vitaliy's memo, with little
    > increase in the error on brightness at max.
    >
    > Vitaliy, I'll get the lightcurves ready to
    > investigate in more detail.
    >
    > Rachel
    >
    > On Sat, 18 Oct 2003, Saul Perlmutter wrote:
    >
    > > ...Also, could you extend the study to z = 1.5?
    > >
    > > --Saul
    > >
    > >
    > >
    > > Saul Perlmutter wrote:
    > >
    > > > Hi Vitaliy, Is it easy for you to check the following
    > things?--
    > > > First, if you assume that you will not be able to get another
    > observation for at least 7 days
    > > > after the discovery does that change anything? (This might
    > be the delay necessary to run the
    > > > search, find the supernova, and request the HST to put the
    > follow-up on the calendar.)
    > > > Second, in the cases in which the supernova is found after
    > maximum, does it help determine
    > > > "stretch" if you include the 3/4-of-an-orbit from 45 days-
    > before-discovery (i.e., from the
    > > > "reference" image taken in the previous iteration of the search)?
    > > > Third, what happens if you only use 7 (or fewer) orbits for
    > the lower-redshift supernovae?
    > > > Fourth, did you check whether you want the sequence of
    > observations to stop at 45 days past
    > > > discovery? Would it be better to extend the schedule of
    > "follow-up" orbits beyond that date
    > > > -- or, alternatively, to end them earlier than your current
    > examples?> >
    > > > --Saul
    > > >
    > > > Vitaliy Fadeyev wrote:
    > > >
    > > > > Dear Searchers,
    > > > >
    > > > > attached please find a short note about the optimization
    > > > > of the observation strategies for the upcoming HST search.
    > > > >
    > > > > The software tools for study were provided by Rob. An essential
    > > > > input is the signal-to-noise tables from Rachel. Undoubtely
    > > > > the study is not yet complete, however some preliminary
    > > > > conclusions can be drawn.
    > > > >
    > > > > Cheers,
    > > > > vitaliy
    > > > >
    > > > > P.S. I will not be around on Monday and Tuesday, but will check
    > > > > emails this weekend.
    > > > >
    > > > > -----------------------------------------------------------
    > -------------
    > > > > Name:
    > HST_search_optimization.ps> > > HST_search_optimization.ps
    > Type: Postscript Document (application/postscript)
    > > > > Encoding: 7bit
    > > > > Download Status: Not downloaded
    > with message
    > >
    >
    >
    >

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