paper

Resolved properties of a luminous "hinge clump" in the compact group of galaxies NGC\,6845

arXiv:2404.11549 · doi:10.1051/0004-6361/202348869

Abstract

We study the properties of one of the most luminous hinge clumps, located on the compact group of galaxies NGC6845. Using IFS from GMOS/Gemini, complemented with archival MUSE data, we obtain oxygen abundances, ages, star formation rates, velocity fields and we also performed a single stellar populations modeling to understand the SFH of the hinge clump localized in NGC6845. We found that the hinge clump sits in a tail, having a SFR of 3.4, which is comparable with a few other extreme cases, e.g., the star clusters in the Antennae galaxy and other reported hinge clumps in the literature. In fact, this clump represents ~15\% of total SFR of NGC6845A. Large-scale modeling of the observed velocity field of NGC6845A rules out the scenario on which this hinge clump was a satellite galaxy. Indeed, its kinematics is compatible with the galactic disk of NGC6845A. Its abundance, mean value of 0.4Z, is also consistent with the metallicity gradient of the galaxy. Our analysis, suggest that the hinge clump is formed by multiple stellar populations instead of a single burst, thus having a large range of ages. We found that central clump is encompassed by a ring-like structure, suggesting that the ring-like structure represents a second-generation of star formation. In addition, the analysis of the diagnostic diagram indicates that this central region can also be being ionized by shock from stellar and supernovae winds. Finally, the derived SFR density of the central clump, place it in starburst regime, where gas inflows should provide gas to maintain the star formation. This work shows a resolved example of an extreme localized starburst in a compact group of galaxies.

arXiv comment13 pages, 11 figures

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