SIXTE: a generic X-ray instrument simulation toolkit

Abstract

We give an overview of the SImulation of X-ray TElescopes (SIXTE) software package, a generic, mission-independent Monte Carlo simulation toolkit for X-ray astronomical instrumentation. The package is based on a modular approach for the source definition, the description of the optics, and the detector type such that new missions can be easily implemented. The targets to be simulated are stored in a flexible input format called SIMPUT. Based on this source definition, a sample of photons is produced and then propagated through the optics. In order to model the detection process, the software toolkit contains modules for various detector types, ranging from proportional counter and Si-based detectors, to more complex descriptions like transition edge sensor (TES) devices. The implementation of characteristic detector effects and a detailed modeling of the read-out process allow for representative simulations and therefore enable the analysis of characteristic features, such as for example pile-up, and their impact on observations. We present an overview of the implementation of SIXTE from the input source, the imaging, and the detection process, highlighting the modular approach taken by the SIXTE software package. In order to demonstrate the capabilities of the simulation software, we present a selection of representative applications, including the all-sky survey of eROSITA and a study of pile-up effects comparing the currently operating XMM-Newton with the planned Athena-WFI instrument. A simulation of a galaxy cluster with the Athena-X-IFU shows the capability of SIXTE to predict the expected performance of an observation for a complex source with a spatially varying spectrum and our current knowledge of the future instrument.

The Athena space X‐ray observatory and the astrophysics of hot plasma†

“…Physical parameter maps reconstructed from seven 100‐ks X‐ray integral field unit observations of a galaxy cluster over regions of S/N 300 (90,000 counts), simulated using the instrument end‐to‐end simulator SIXTE (Dauser et al ). The cluster is located at z = 0.1, with R 500 = 1.1 Mpc, and T 500 = 4.2 keV.…”

“…Some cooling and star formation are seen, but the rates are much lower than would be expected without feedback. The low level of turbulence measured in the Perseus cluster by Hitomi (Hitomi Collaboration et al 2016) and in some other clusters with the XMM-Newton reflection grating spectrometer (RGS) (see F I G U R E 5 Physical parameter maps reconstructed from seven 100-ks X-ray integral field unit observations of a galaxy cluster over regions of S/N 300 (90,000 counts), simulated using the instrument end-to-end simulator SIXTE (Dauser et al 2019). The cluster is located at z = 0.1, with R 500 = 1.1 Mpc, and T 500 = 4.2 keV.…”

Toward the low-scatter selection of X-ray clusters

“…The simulations of the extragalactic eROSITA sky were performed using the Monte Carlo based SIXTE simulator (Dauser et al 2019). A sample of photons was produced based on the effective area of the instrument and input source characteristics, for example, a source spectrum, or if necessary, a model of the extent.…”

GPU Supported Simulation of Transition-Edge Sensor Arrays

“…(6)] and load resistor [Eq. (7)] as well as thermal fluctuation noise between the TES and heat bath [Eq. (5)], where M P is a factor we introduced to scale the phonon noise level to match measurements.…”

“…The input of the simulator is a list of X-ray photon impacts containing energies, arrival times and impact positions on the pixel array. If one wants to simulate an observation of an astrophysical source, such a list can also be generated with the Simulation of X-ray Telescopes (SIXTE) software package, 1 a generic Monte Carlo-based simulation toolkit for observations with astronomical instruments [6,7]. The output of xifusim is a list of records that contains the digitized signal of all detected current pulses during the simulation.…”