GEHONG: A Python Package for Simulating IFS Spectral Data Cubes

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GEHONG (GEnerate tHe data Of iNtegral field spectrograph of Galaxy) is a Python package developed for simulating high-resolution, three-dimensional (3D) spectroscopic data cubes observed with ideal integral field spectrographs (IFS). It is specifically designed to support the science preparation of the Chinese Space Station Telescope Integral Field Spectrograph (CSST-IFS), but is also applicable to other IFS instruments.

Given two-dimensional maps describing spatially resolved physical properties of target sources, such as stellar population, surface brightness, line-of-sight velocity, and gas-phase metallicity, GEHONG generates synthetic 3D datacubes by assembling position-dependent one-dimensional spectra. These spectra can be composed of up to four components:

  • stellar continuum

  • ionized gas emission lines

  • AGN spectra

  • individual stellar spectra

GEHONG is capable of producing mock observations of a wide range of astrophysical systems, including galaxies, AGNs, star clusters, and H II regions. The input parameter maps can be derived from either analytic models, observational data, or hydrodynamic simulations.

GEHONG plays a key role in simulating idealized datacubes for CSST-IFS scientific pre-studies. These datacubes can serve as inputs for:

  • the CSST-IFS raw image simulator (CSST-IFS-SIM), which generates mock CCD images from ideal datacubes. Online access

  • the exposure time calculator (CSST-IFS-ETC), which estimates the signal-to-noise ratio of mock observations and helps optimize exposure configurations. This tool can be accessed both as a Python package and via a web-based interface

  • other planning tools for observation simulation and survey strategy design

Project Info

This project is supported by the CSST scientific data processing and analysis system of the China Manned Space Project, Shanghai Academic/Technology Research Leader (22XD1404200), the National Key R&D Program of China (No 2022YFF0503402 ) and the China Manned Space Project with No. CMS-CSST-2025-A07.