JASMINE image simulator for high-precision astrometry and photometry

TL;DR

JASMINE-image sim is a software tool developed for realistic simulation of space-based astrometric observations, aiding mission planning by identifying potential issues like jitter and timing errors that affect measurement accuracy.

Contribution

The paper introduces JASMINE-imagesim, a new simulation software that models realistic observational conditions for the JASMINE space mission, including jitter and noise factors.

Findings

Simulation confirms 4 mas accuracy for 12.5-mag objects is achievable with uniform PSF dilution.

Realistic jitter and timing differences can significantly degrade measurement accuracy.

Simulation helps identify critical issues and develop countermeasures for the mission.

Abstract

JASMINE is a Japanese planned space mission that aims to reveal the formation history of our Galaxy and discover habitable exoEarths. For these objectives, the JASMINE satellite performs high-precision astrometric observations of the Galactic bulge and high-precision transit monitoring of M-dwarfs in the near-infrared (1.0-1.6 microns in wavelength). For feasibility studies, we develop an image simulation software named JASMINE-imagesim, which produces realistic observation images. This software takes into account various factors such as the optical point spread function (PSF), telescope jitter caused by the satellite's attitude control error (ACE), detector flat patterns, exposure timing differences between detector pixels, and various noise factors. As an example, we report a simulation for the feasibility study of astrometric observations using JASMINE-imagesim. The simulation confirms that the required position measurement accuracy of 4 mas for a single exposure of 12.5-mag objects is achievable if the telescope pointing jitter uniformly dilutes the PSF across all stars in the field of view. On the other hand, the simulation also demonstrates that the combination of realistic pointing jitter and exposure timing differences in the detector can significantly degrade accuracy and prevent achieving the requirement. This means that certain countermeasures against this issue must be developed. This result implies that this kind of simulation is important for mission planning and advanced developments to realize more realistic simulations help us to identify critical issues and also devise effective solutions.