Step Arguments

The reference pixel correction step has seven step-specific arguments:

  • --odd_even_columns

If the odd_even_columns argument is given, the top/bottom reference signal is calculated and applied separately for even- and odd-numbered columns. The default value is True, and this argument applies to NIR data only.

  • --use_side_ref_pixels

If the use_side_ref_pixels argument is given, the side reference pixels are used to calculate a reference signal for each row, which is subtracted from the data. The default value is True, and this argument applies to NIR data only.

  • --side_smoothing_length

The side_smoothing_length argument is used to specify the height of the window used in calculating the running median when calculating the side reference signal. The default value is 11, and this argument applies to NIR data only when the --use_side_ref_pixels option is selected.

  • --side_gain

The side_gain argument is used to specify the factor that the side reference signal is multiplied by before subtracting from the group row-by-row. The default value is 1.0, and this argument applies to NIR data only when the --use_side_ref_pixels option is selected.

  • --odd_even_rows

If the odd_even_rows argument is selected, the reference signal is calculated and applied separately for even- and odd-numbered rows. The default value is True, and this argument applies to MIR data only.

  • --ovr_corr_mitigation_ftr

This is a factor to avoid overcorrection of intermittently bad reference pixels in the IRS2 algorithm. This factor is the number of sigmas away from the mean. The default value is 3.0, and this argument applies only to NIRSpec data taken with IRS2 mode.

  • --preserve_irs2_refpix

If the preserve_irs2_refpix argument is set, interleaved reference pixels in IRS2 mode will be processed along with the normal pixels and preserved in the output. This option is intended for calibration or diagnostic reductions only. For normal science operation, this argument should always be False, so that interleaved pixels are stripped before continuing processing.

  • --refpix_algorithm

The refpix_algorithm argument is only relevant for all NIR full-frame data, and can be set to ‘median’ (default) to use the running median or ‘sirs’ to use the Simple Improved Reference Subtraction (SIRS).

  • --sigreject

The sigreject argument is the number of sigmas to reject as outliers in the SIRS algorithm. The value is expected to be a float.

  • --gaussmooth

The gaussmooth argument is the width of Gaussian smoothing kernel to use as a low-pass filter. The numerical value is expected to be a float.

  • --halfwidth

The halfwidth argument is the half-width of convolution kernel to build. The numerical value is expected to be an integer.