From: Vallery Stanishev (vall@physto.se)
Date: Thu Apr 22 2004 - 09:17:57 PDT
Hi,
I started working on the grism data. On the bottom of the Twikki page
some figures can be seen. The SN is visible but the signal is very low
and in addition the spectrum is heavily contaminated by the close bright
galaxy. Have to find a way to get rid of it before any extraction of the
spectrum is attempted.
Another problem is that the direct image is too shalow and the position
of the SN could not be accurately determined. This will affect the
accuracy of the wavelength solution. I put some rough wavelength marks
on one of the 2D images.
On the third image (not directly visible from the page) are shown the
output of Multidrizzle and simpe shift & add. They seem to be almost
identical. The shifts for the "shift & add" image were determined from
the 0th orders of 4 bright compact sourses on CCD2. The images were
shifted by IRAF's IMSHIFT with frac. pixel shifts and interpolation type
'drizzle[0.5]'. For the multidrizzle image shifts were not supplied and
the info comes from the headers (for the moment). PIXFRAC and SCALE 1
were used.
Vallery
Rachel A. Gibbons wrote:
> Hi,
>
> Tony noticed that in my previous e-mail the days past discovery should
> read
>
> 1) 9 days (~3.5 rest frame days)
>
> 2) 13 days (~5 rest frame days).
>
> However, my conclusions are based on the correct scaling. Also, to be
> precise, the data are consistent with discovery at rest B max. Sorry for
> any confusion.
>
> Rachel
>
> On Mon, 19 Apr 2004, Rachel A. Gibbons wrote:
>
>
>>Hi everyone,
>>
>> It would appear our data are completely consistent with a supernova at
>>z=1.6 which was discovered at rest-frame optical maximum.
>>
>> Here's an update from the first round of follow-up ACS and NICMOS
>>photometry :
>>
>> 1) The discovery z' magnitude was z'=25.1 and 12 days later z'=25.5.
>>
>> 2) 16 days after discovery, the new J and H magnitudes are 24.37 and
>>24.03.
>>
>> All mags quoted here are Vega.
>>
>> The remainder of the follow-up observations for this candidate will be
>>in J & H and will extend through 23 May (yes, that's during the next
>>search run).
>>
>> It's unfortunate we're following it on the decline, but it's looking
>>good! Hooray!
>>
>>Rachel
>>
>>PS Sorry, no news yet to report on the grism data, except that we have it
>> and they pointed HST at the right part of the sky.
>>
>
>
>
-- ******************************************************** Dr. Vallery Stanishev Stockholm University AlbaNova University Center FYSIKUM 106 91 Stockholm SWEDENtel: +46 8 55378731 fax: +46 8 55378601 vall@physto.se vall_1@yahoo.com ********************************************************
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