WARM IRAC ONLY: Aperture Corrections
We have derived corrections for aperture photometry performed on
data taken during the warm mission. These corrections differ very
slightly (less than 1%) from the corrections given in the
IRAC Instrument Handbook
section 4.10, Table 4.7. To use the table of
warm corrections, perform your photometry with an aperture of radius
given in native IRAC pixels (the size of which in arcseconds is
given in Table 2.1 in Section 2.2.1 "IRAC Image Quality" in the
IRAC Instrument Handbook) and measure the sky background in an
annulus limited by the radii given by the two latter two numbers in
the first column of the new table. Thus, for example, aperture
entry 2_2_6 corresponds to performing aperture photometry in a
radius of two native IRAC pixels and measuring the subtracted
background in an annulus between two and six native IRAC pixels.
Please note that for crowded regions, performing PRF-fitting may
yield more accurate results. Please refer to the
IRAC Instrument Handbook,
MOPEX documentation
and the Spitzer Data Analysis Cookbook
for instruction on how to perform PRF-fitting photometry.
The aperture corrections should be multiplied by the measured
aperture photometry total flux densities to derive corrected
flux densities.
The first number in the lefternmost column gives
the aperture radius in pixels, and the second and
third numbers give the background annulus inner
and outer radii in pixels.
Aperture | CH1 | CH2 |
2_2_6 | 1.2132 | 1.2322 |
2_12_20 | 1.2026 | 1.2228 |
3_3_7 | 1.1233 | 1.1336 |
3_12_20 | 1.1132 | 1.1126 |
4_12_20 | 1.0736 | 1.0809 |
5_5_10 | 1.0588 | 1.0625 |
5_12_20 | 1.0482 | 1.0500 |
6_12_20 | 1.0315 | 1.0349 |
8_12_20 | 1.0112 | 1.0125 |
12_12_20 | 0.9931 | 0.9913 |
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