From: Robert A. Knop Jr. (robert.a.knop@vanderbilt.edu)
Date: Sun May 12 2002 - 05:54:39 PDT
I've performed subtractions of SDFe, doing sums of each chip that
include the dithers from neighboring chips that overlap that chip. This
reduces the problem with previous union sums where the S/N gets very bad
around the edges due to many fewer images being summed. There are still
bad spots, but now they correspond to the edges of the *array* rather
than the edges of each chip.
The subtractions are reasonable clean, although the noisy spots at the
edges of the array contribute a lot of spurios "candidates" that are
just fluctuations. There are also a number of dipole-shaped things
associated with bright objects, indicating not-perfect aligment between
the new and the ref. However, I think the subtractions are pretty good.
The new subtractions are SDFe_overlapunion_* where * is the chip (a
through j). You can find them near (but not at) the bottom in
scanmonitor.
The zeropoints in these subtractions are, suprise surprise, screwed.
I've gone and scanned them; I found four (really, five, but one was
already known) of Naoki's candidates (summarized below). I have *not*
gone through and explicitly tried to find Naoki's candidates. That
still needs to be done.
I also found S02-066 again... I didn't like the way it looked. I have
not tried to systematically go through and look at all preexisting
candidates. There were some bad transformations between their refsys
and the refsys of this subtraction, so their positions won't have been
calculated properly on the new subtractions. Be warned if you go
looking for "Preexisting candidates". (The way to fix it is to fix the
candidate's refsys and the subtraction's refsys with ftransimages2 and,
probably, /manual,/clobber.)
Naoki's remaining candidates have not yet been entered into SNTrak.
Reason: Alex and NRL may want to work harder on finding them with the
IDL software tomorrow, and saving them to SNTrak that way (so that
things like Refsys, etc. are in there).
> B SDFe1 13:25:45.09 +27:19:10.4 23.53 637.89 faint host seen in Apr
===> Found as S02-084
> C SDFe2 13:27:14.97 +27:25:33.4 25.14 21.38 almost center, AGN?
(not yet found)
> A SDFe3 13:26:07.27 +27:32:17.0 25.28 229.46 faint host seen in Apr
==> Found as S02-082
> B SDFe4 13:26:37.35 +27:29:10.5 24.32 32.52 Visible in Apr
==> Found as S02-085
> B S02-064 SDFe5 13:25:46.62 +27:34:21.1 22.44 101.76 Visible in Apr
==> (Found again. Note: coordinate in SNTrak is way different!)
> C SDFe6 13:26:17.78 +27:37:04.1 25.91 3.34 0.5pix off-center, AGN?
(not yet found)
> A SDFe7 13:26:35.69 +27:35:56.2 25.35 31.05 faint host seen in Apr
==> Found as S02-083
> B SDFe8 13:26:15.01 +27:41:07.1 25.07 -4184.4 nothing in Apr
(not yet found)
I have been awake for nearly 26 hours in a run now. I am going to go to
sleep, and will not be availble or online until Sunday afternoon.
-Rob
This archive was generated by hypermail 2.1.4 : Sun May 12 2002 - 05:55:00 PDT