> From: Adrienne Cool <cool@quark.sfsu.edu>
>
> 1. Is anyone aware of documentation explaining how celldetect
> or wavdetect) make their final determination of positions?
> Some of the positions I get look pretty bad. Is there
> any way to adjust the parameters they use to make these
> determinations (e.g. a radius within which pixels are
> included in the final source position determination)?
Hello Adrienne,
WAVDETECT computes source positions by taking the simple
counts-weighted average of all the photons in the source
cell. The size and shape of the source cell differs from
source to source, but is expected to enclose >90% of the
source photons. For weak sources at large off-axis angles,
background contamination will affect both photometry and
astrometry, but does not affect the significance of the
detection itself.
> 2. Is there any way to avoid having positions reported as
> ellipses, and just get (e.g.) 90% confidence radii on
> positions?
The XERR and YERR columns in the final output table are 1-sigma
estimates of the uncertainty on the position determined as
described above.
Vinay
This archive was generated by hypermail 2b29 : Thu Dec 13 2012 - 01:00:06 EST