3.1.2. Aerror: Estimate atomic data errors for model parameters

3.1.2.1. Overview

This command calculates the atomic error on a certain parameter of the {it cie} model. 1 \sigma error (68% confidence level) is calculated. The atomic error is estimated based on the approach in Gu et al. (2022). In this paper, the uncertainties on the line emissivities of the cie model are estimated by comparing the model with the observed spectra of stellar coronae and a cluster of galaxies.

The current estimation is based on a pre-calculation of atomic errors as a function of electron temperature and Fe abundance. The value is obtained with a two-dimensional interpolation of the temperature and Fe abundance grids defined in the pre-calculation.

Note that the current estimation does not cover notable error sources including in particular the ion concentration and wavelength uncertainties. These components can be assessed by comparing the fits with different balance standards, and by shifting the line centers manually in the model.

For the Fe abundance, there are three types of atomic errors available: error with the Fe-L shell, the K shell, and using the entire band. Users can switch between the three bandpasses by setting the Shell value. If the target parameters (e.g., abundances) are determined by few isolated lines, it is also possible to calculate the atomic error manually using the analytic emissivity-uncertainty relation introduced in Gu et al. (2022).

Note

This command only works for the CIE model.

3.1.2.2. Syntax

aerror #i1 #i2 #a shell #i3: Determine the atomic error for the parameter specified by the sector #i1 (optional), component #i2 (optional) and parameter #a (optional). If not specified, the range for the last call will be used. On startup, this is the first parameter of the first component of the first sector. Shell #i3 (0: full band, 1:L-shell, 2:K-shell) sets the band used to calculate the Fe abundance error.

3.1.2.3. Examples

aerror norm: Give the atomic error for the emission measure of the current component.
aerror 2 26 shell 1: Calculate the error for the Fe abundance of component 2 using the L-shell part.

Recommended citation: Gu et al. (2022)