Mock Observations for the CSST Mission: Main Surveys-the Slitless Spectroscopy Simulation

TL;DR

This paper presents a simulation framework for the CSST's slitless spectroscopic system, analyzing its properties and detection performance to aid in data processing development before real observations begin.

Contribution

It introduces a novel simulation framework for the CSST slitless spectroscopic system, enabling performance assessment and aiding in pipeline development.

Findings

Nearly all 1st order spectra have corresponding 0th order images.

GI spectral band shows higher detection efficiency than GV and GU bands.

Simulation results support the primary use of the GI band for stellar and galactic observations.

Abstract

The China Space Station Telescope (CSST), slated to become China's largest space-based optical telescope in the coming decade, is designed to conduct wide-field sky surveys with high spatial resolution. Among its key observational modes, slitless spectral observation allows simultaneous imaging and spectral data acquisition over a wide field of view, offering significant advantages for astrophysical studies. Currently, the CSST is in the development phase and lacks real observational data. As a result, the development of its data processing pipeline and scientific pre-research must rely on the mock data generated through simulations. This work focuses on developing a simulation framework for the CSST slitless spectral imaging system, analyzing its spectral dispersing properties and structural design. Additionally, the detection performance of the slitless spectral system is assessed for various astrophysical targets. Simulation results demonstrate that nearly all 1st order spectra are accompanied by corresponding 0th order images, facilitating accurate source identification. Furthermore, the GI spectral band exhibits superior detection efficiency compared to the GV and GU bands, establishing it as the primary observational band for stellar and galactic studies. This work successfully develops a simulation framework for the CSST slitless spectroscopic equipment.