Unit conventions

DSF uses Mpc/h for user-facing radial quantities, including forecast inputs and saved forecast outputs.

Different components of the pipeline follow different internal conventions, with conversions handled by the forecast builder.

Radial distances

The radial conventions are:

• Covariance: Mpc/h.

• Data vector: Mpc, following the CCL convention.

• Forecast builder: converts input radii from Mpc/h to Mpc before evaluating the CCL-backed data vector.

Unless otherwise stated, projected radii, radial bin edges, and forecast radius grids are expressed in Mpc/h.

Excess surface density

The excess surface density is defined as

\[\Delta\Sigma(R) = \overline{\Sigma}(<R)-\Sigma(R),\]

where \(\overline{\Sigma}(<R)\) is the mean projected surface density enclosed within radius \(R\), and \(\Sigma(R)\) is the projected surface density at that radius.

The forecast data vector currently reports \(\Delta\Sigma\) in \(M_\odot/\mathrm{pc}^2\), with projected radii in Mpc/h.

The covariance calculation uses a critical-surface-density prefactor intended for distances in Mpc/h and \(\Delta\Sigma\)-like quantities in \(M_\odot h/\mathrm{pc}^2\).

Important

The data-vector and covariance modules use different internal conventions. Their relative normalization must be accounted for when combining predictions and covariance matrices.