Star Formation History of the WLM and NGC 6822 Using STIS Photometry

摘要

We present results of a star formation history analysis of the two local group dwarf galaxies Wolf-Lundmark-Melotte (WLM) and NGC 6822. We used Space Telescope Imaging Spectrograph (STIS) archival images of several fields in the clear and long-pass filter configuration and followed the calibration ideas of [1]. To derive the star formation history we applied the StarFISH code written by [2]. The data of the WLM was primarily used as a calibration set. Our analysis recovered features consistent with previous studies, i.e. like a more burst-like star formation history. In case of NGC 6822 we found evidence for significant local variations of the star formation history. While northern regions contain younger populations, the southern regions favors older ones, reminding one of a more burst-like star formation history than a continuous one.