MOPEX User's Guide - IRSA

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DISCUSSION
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6.5.4 APEX Modules: S/N Estimator
Command Line Equivalent: compute_uncertainties_internally
Default Output Directory: /Sigma-apex
De pe nds On: Initial Settings; APEX Settings
Relevant Pipelines: All
MOPEX User’s Guide
Important Notes: Only required if you do not have the uncertainty images that come with all
Spitzer data.
PURPOSE
This module is used to estimate the uncertainty images when no independent uncertainty
measurement is available. This module is usually not turned on since almost all Spitzer data
have independent uncertainty images (*unc*.fits) that come downloaded with Spitzer data
from the archive. If you decide not to use the provided uncertainty images, or if you are not
using Spitzer data, this module needs to be switched on. Warning: if the wrong Gain or Read
Noise parameters are specified, this module may produce uncertainties that are too large, and
this will result in no outlier detection.
INPUT
Gain in e-/image unit: (float) This is the parameter used to translate the measured data
counts to physical units of MJy/sr (or mJy/sq.arcsec). All Spitzer BCDs are in units of
MJy/sr. This parameter has the same name as stored in the Spitzer BCD FITS he ade r,
but they have different units. MOPEX Gain has the unit of e-/MJy/sr (or e-/mJy/sq.arcsec)
and the FITS header GAIN has the unit of e-/DN. Gain used by MOPEX can be computed
from the GAIN parameter in the FITS header by using formula:
Gain(MOPEX) =
EXPTIME *GAIN(header)
FLUXCONV
Equation 6.1
Point Source Extraction (APEX) 114
APEX Modules