2025/03/05 by Devang Somawanshi, Somawanshi, Devang, Souradeep Bhattacharya +8 · 1 voice
Physics and Astronomy · #Astronomy and Astrophysical Research #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies #astro-ph.GA
paper · pdf · doi:10.48550/arxiv.2503.03242
arxiv published 2025/03/05 · arxiv updated 2025/05/11
Integral field unit (IFU) spectroscopic observations of resolved galaxies provide an optimal experimental setting for determination of stellar population properties, in particular - age, metallicity and α-enhancement, which are key to understanding evolution of galaxies across diverse physical environments. We determine these properties for the edge-on disc galaxy IC 1553, through stellar population models fitted to MUSE IFU observations. From our determined spatial distributions of metallicity and [α/Fe], we serendipitiously identify the unique chemical signature of a dwarf galaxy that is co-spatial with the luminous disc of IC 1553. The dwarf galaxy is characterized by the presence of higher [α/Fe] and metal-poor stellar populations relative to the disc of IC 1553. The identified dwarf is dynamically cold from its determined kinematics, consistent with being a satellite of IC 1553. From modeling the Spitzer IRAC 3.6 μm image of IC 1553, we confirmed the presence of the dwarf galaxy and calculated its stellar mass to be ∼1.28× 109 \rm~M\odot. This is the first such identification of a dwarf galaxy from its unique chemical signature in such integrated light IFU observations, even though its hidden by the luminous body of its massive host.