Star Formation in the Extreme Outer Galaxy: the IMF in a low metallicity environment

TL;DR

This study uses deep near-infrared imaging to investigate the initial mass function (IMF) in the low-metallicity environment of the extreme outer Galaxy, finding it similar to that in more metal-rich regions.

Contribution

First deep NIR imaging survey of young clusters in the EOG to examine the IMF in a low-metallicity environment, providing new insights into star formation under such conditions.

Findings

IMF in low metallicity environment down to 0.1 M_sun is similar to typical IMFs.

Deep NIR images of Digel Cloud 2 clusters obtained with Subaru.

No significant difference in the IMF compared to nearby star clusters.

Abstract

We are conducting a deep near-infrared (NIR) imaging survey of young embedded clusters in the extreme outer Galaxy (hereafter EOG), at the Galactic radius (R_g) of more than 18 kpc. The EOG is an excellent laboratory to study the nature of the IMF in a low-metallicity environment with a great advantage of the proximity compared to nearby dwarf galaxies, such as LMC & SMC. As a first step, we obtained deep NIR images of Digel Cloud 2 clusters at R_g ~19 kpc using the Subaru 8.2-m telescope. The observed K-band luminosity function shows that IMF in the low metallicity environment down to ~ 0.1 M_{sun} is not significantly different from the typical IMFs in the field and in the nearby star clusters as was suggested in our earlier work.