Re: Comments on February 6th draft

From: Chris Lidman (clidman@eso.org)
Date: Mon Feb 09 2004 - 08:55:05 PST

  • Next message: Chris Lidman: "More on IR photometry"

    Hi Serena,
      Sorry, I should have said paragraph 4 of section 5; the one that
    starts with "A general problem ..." I think this paragraph should be
    removed.

      It is difficult to judge what one should use as a systematic
    uncertainty in the IR-optical colours. I think that 0.02 to 0.03
    is reasonable if we were to move the IR photometry of Beethoven
    to the Bessell (BB) system.

      The A0V stars in the Hipparcos catalogue have V-J_BB=0.03-0.04 on
    the Bessell system. The reason for the non-zero colour may be
    extinction, but this is an assumption, which is probably testable.
    If you do not move the Beethoven photometry to the Bessell system,
    then the systematic error in R-J (restframe B-I) is around 0.05.

      The other two SN are more problematic as we do not know which IR
    system they use, although this is something we may be able to gather
    from the papers. A systematic uncertainty in the optical-IR colours
    of 0.05 is probably reasonable.

      To summarise, if you do nothing to the paper as it is now, then use
    0.05 as the systematic error in the IR-optical colours. If you correct
    the J-band photometry of Beethoven (and it is the only one you can
    correct at this stage), then use 0.03 magnitudes it and 0.05 for the
    rest.

    Cheers, Chris.

     
      

    On Mon, 2004-02-09 at 12:29, Serena Nobili wrote:
    > Dear Chris
    >
    > thanks for your comments. Can you please point me again to which paragraph
    > you would like me to remove? (Paragraph 4 of which section?) Also, as I
    > understand from your previous e-mail, there is still about 0.02 mag
    > uncertainty between the different systems. Should we really remove
    > completely the discussion or perhaps we should just re-phrase it in a
    > softer way?
    > Cheers
    >
    > Serena
    >
    >
    > On 8 Feb 2004, Chris Lidman wrote:
    >
    > >
    > >- Paragraph 4. I think that this paragraph should be removed as modern
    > >IR standard star systems are just as good as visual standard star
    > >systems. It comes down to the care the observer takes in choosing a
    > >suitable set of standards and to knowing how one standard star system
    > >relates with another. Thanks to 2MASS, the relationship between systems
    > >is better understood.
    > >
    >
    >
    >
    >
    >
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