RelxillA is completely base on relxill (García,Dauser et al), please see and follow relxill for installation and more details.
RelxillA is an angle-improved relxill-type model which designed for next-generation instrument NewAthena/X-IFU and LAD.
As show in Huang et al (2025), relxillA simply improves the calculation of the emission angle and predicts slightly different spectra with respect to older models.Therefore it does not introduce any new parameter degeneracy. And relxillA can fit well the simulated observations of Liu et al (2025).
A key improvement in relxillA is its handling of the local emission spectrum. While relxill uses a single spectrum averaged over all emission angles, relxillA calculates the contribution from a series of discrete angular bins, as detailed in the following figure:
We showed that the approximations implemented in relxill and relxill_nk are unsuitable to fit high-quality full reflection spectra (Liu et al (2025)), which require instead reflection models with more accurate calculations of the emission angle.
