Testing the robustness of DYNAMITE triaxial Schwarzschild modelling: The effects of correcting the orbit mirroring

¹ Department of Astrophysics, University of Vienna, Türkenschanzstraße 17, 1180 Vienna, Austria
e-mail: sabine.thater@univie.ac.at
² Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030, PR China
³ Department of Astronomy and Space Sciences, University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, PR China
⁴ Leibniz-Institute for Astrophysics Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany
⁵ School of Physics, University of New South Wales, NSW 2052, Australia
⁶ ARC center of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), Sydney, Australia
⁷ Center for Extragalactic Astronomy, University of Durham, Stockton Road, Durham DH1 3LE, UK
⁸ Sterrewacht Leiden, Leiden University, Postbus 9513, 2300 RA Leiden, The Netherlands
⁹ Max Planck Institute for extraterrestrial Physics, Giessenbachstraße 1, 85748 Garching, Germany
¹⁰ SDB Science-driven Business Ltd, 85 Faneromenis Avenue, Ria Court 46, Suite 301, 6025 Larnaca, Cyprus
¹¹ DiSAT, Università degli Studi dell’Insubria, via Valleggio 11, 22100 Como, Italy
¹² INAF, Osservatorio Astronomico di Brera, Via E. Bianchi 46, 23807 Merate, Italy
¹³ INFN, Sezione di Milano-Bicocca, Piazza della Scienza 3, 20126 Milano, Italy
¹⁴ European Space Agency, European Space Research and Technology Centre, Keplerlaan 1, 2200 AG Noordwijk, The Netherlands

Received: 2 May 2022
Accepted: 8 August 2022

Abstract

In the past 15 yr, the triaxial Schwarzschild orbit-superposition code developed by van den Bosch and van de Ven in Leiden has been widely applied to study the dynamics of galaxies. Recently, a bug was reported in the orbit calculation of this code, specifically in the mirroring procedure that is used to speed up the computation. We have fixed the incorrect mirroring in the DYNAMITE code, which is the publicly-released successor of the Leiden triaxial Schwarzschild code. In this study, we provide a thorough quantification of how this bug has affected the results of dynamical analyses performed with this code. We compare results obtained with the original and corrected versions of DYNAMITE, and discuss the differences in the phase-space distribution of a single orbit and in the global stellar orbit distribution, in the mass estimate of the central black hole in the highly triaxial galaxy PGC 46832, and in the measurement of intrinsic shape and enclosed mass for more than 50 galaxies. Focusing on the typical scientific applications of the Schwarzschild method, in all our tests we find that differences are negligible with respect to the statistical and systematic uncertainties. We conclude that previous results with the Leiden triaxial Schwarzschild code are not significantly affected by the incorrect mirroring.