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Background Estimates in Sensitivity Plots

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The background estimates were generated using a prototype version of the Spitzer background estimator. Three lines of sight were chosen to represent low, medium, and high background.

Line of Sight Parameters

GalacticEcliptic
LongitudeLatitudeLongitudeLatitude
low96+3023989
medium105-201040
high187+1910

Background Contributions

The background model includes the zodiacal light, interstellar medium (cirrus), and the cosmic infrared background (at wavelengths greater than 100 microns). The contributions of each component can be seen in the figure below. The zodiacal light dominates IRAC and IRS wavelengths for all these lines of sight. For MIPS 70 microns, there are comparable interstellar and zodiacal contributions, while at 160 microns, the interstellar contribution dominates.


Brightness Values

The background spectra were integrated over the Spitzer passbands and the results are reported as per the Spitzer calibration convention (same as IRAS, ISO, COBE) below. The first column is the mnemonic wavelength for the band and the second column is the quoted surface brightness of that band. For reference, the color corrections ranged from 0.98 to 1.08.

    A. Low-background
    Wavelength
    (microns)
    Background
    (MJy/sr)
    3.600000.0769
    4.500000.267
    5.800001.37
    8.000005.47
    15.750016.8
    22.250016.7
    24.000016.1
    70.00005.15
    160.0006.53

    B. Medium-background

    Wavelength
    (microns)
    Background
    (MJy/sr)
    3.60000 0.125
    4.50000 0.366
    5.80000 1.93
    8.00000 7.69
    15.7500 24.4
    22.2500 24.7
    24.0000 23.9
    70.0000 8.95
    160.000 16.5

    C. High-background

    Wavelength
    (microns)
    Background
    (MJy/sr)
    3.60000 0.43
    4.50000 0.85
    5.80000 4.64
    8.00000 18.3
    15.7500 63.1
    22.2500 67.0
    24.0000 65.6
    70.0000 32.3
    160.000 84.3