A near-ultraviolet view of the Inner Region of M31 with the Large Binocular Telescope

TL;DR

This study provides a detailed near-ultraviolet view of M31's inner region using the Large Binocular Telescope, revealing star formation structures, dust lanes, and discovering new stellar clusters.

Contribution

First high-resolution near-ultraviolet imaging of M31's inner region with the LBT, identifying new stellar clusters and analyzing the galaxy's fine dust and star formation structures.

Findings

Discovered 6 new candidate stellar clusters.

Confirmed and characterized 124 globular clusters.

Revealed detailed dust lane structures and star formation regions.

Abstract

We present a 900 sec, wide-field U image of the inner region of the Andromeda galaxy obtained during the commissioning of the blue channel of the Large Binocular Camera mounted on the prime focus of the Large Binocular Telescope. Relative photometry and absolute astrometry of individual sources in the image was obtained along with morphological parameters aimed at discriminating between stars and extended sources, e.g. globular clusters. The image unveils the near-ultraviolet view of the inner ring of star formation recently discovered in the infrared by the Spitzer Space Telescope and shows in great detail the fine structure of the dust lanes associated with the galaxy inner spiral arms. The capabilities of the blue channel of the Large Binocular Camera at the Large Binocular Telescope (LBC-Blue) are probed by direct comparison with ultraviolet GALEX observations of the same region in M31. We discovered 6 new candidate stellar clusters in this high-background region of M31. We also recovered 62 bona-fide globulars and 62 previously known candidates from the Revised Bologna Catalogue of the M31 globular clusters, and firmly established the extended nature of 19 of them.