Session 87 - Large Scale Structure.
Display session, Friday, January 09
Exhibit Hall,

## [87.03] Estimation of Cosmic Infrared Background Errors from Zodiacal Light Modeling Errors

E. L. Wright (UCLA)

The zodiacal light modeling technique used by Kelsall et al. (1998) and Wright (1998) assumes that the galactic plus cosmic infrared background (CIB) signal is constant in time at each pixel, and the fitting algorithm adjusts the model parameters to minimize the time variations. This approach is guaranteed to not remove any CIB component. Because it makes minimal assumptions about the galactic plus CIB sky, I call this the ``weak no-zodi principle''. But since there are systematic residuals in the fit, there will be systematic errors in the zodiacal light models whose effects on the derived CIB are difficult to quantify. Two different fitting techniques are given here that force the fitting algorithm to give systematically different results even for the same parameterized model. These are the ``strong no-zodi principle'' which asks that the high galactic latitude sky at 25 \mum be isotropic in addition to asking that the galactic plus CIB signal be constant in time for each pixel at each wavelength; and the ``very strong no-zodi principle'' which requires in addition that the isotropic high |b| 25 \mum sky have some specified value. These added constraints force the modeled zodiacal dust cloud to have a different shape. The effect of this systematic shift in shape on the zodiacal light ``windows'' at 3.5 and 240 \mum can then be estimated.