These data challenges are in support of the study of the imager option for a Probe-class CMB mission. We will use it as a check on analytic forecasts, and to further optimize the baseline design.

We are at the very beginning stages of defining this data challenge. Nothing written here should be understood as finalized. Please feel free to contribute to the definition of the data challenge.

Following the model used in CMB-S4, we will define Data Challenge X.Y as the application of Mission Model X to Sky Model Y.

Data challenges will be made available at NERSC at /project/projectdirs/cmbp/dc_X.Y

To obtain a NERSC account please go to http://crd.lbl.gov/cmb to sign-up, using repository mp107 and PI Borrill.

A mission model includes an Instrument Model and an Observation Model

A basic instrument model will include specification of each frequency band:

• Center and width
• Angular resolution
• Sensitivity

An advanced instrument model will also include:

• Focal plane layout
• Noise model for each detector
• Cooler cycle frequency & duration (if any)

An observation model defines the scanning strategy

• Spin access
• Spin rate
• Precession axis
• Precession rate
• Survey duration

and any polarization modulation

• HWP rotation rate or stepping frequency and angle

A sky model comprises four elements:

• Scalar, tensor and non-Gaussian CMB
• Extragalactic foregrounds, including their lensing.
• Galactic foregrounds
• Zodiacal emission