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Stellar halos offer fossil evidence for hierarchical structure formation.Since halo assembly is predicted to be scale-free, stellar halos aroundlow-mass galaxies constrain properties such as star formation in the accretedsubhalos and the formation of dwarf galaxies. However, few observationalsearches for stellar halos in dwarfs exist. Here we present gi photometry ofresolved stars in isolated Local Group dwarf irregular galaxy IC 1613($M_{\star} \sim 10^8 M_{\odot})$. These Subaru/Hyper Suprime-Cam observationsare the widest and deepest of IC 1613 to date. We measure surface densityprofiles of young main-sequence, intermediate to old red giant branch, andancient horizontal branch stars outside of 12' ($\sim 2.6$ kpc; 2.5 half-lightradii) from the IC 1613 center. All of the populations extend to ~24' ($\sim5.2$ kpc; 5 half-light radii), with the older populations best fit by a brokenexponential in these outer regions. Comparison with earlier studies sensitiveto IC 1613's inner regions shows that the density of old stellar populationssteepens substantially with distance from the center; we trace the $g$-bandeffective surface brightness to an extremely faint limit of $\sim 33.7$ magarcsec$^{-2}$. Conversely, the distribution of younger stars follows a single,shallow exponential profile in the outer regions, demonstrating differentformation channels for the younger and older components of IC 1613. Theoutermost, intermediate-age and old stars have properties consistent with thoseexpected for accreted stellar halos, though future observational andtheoretical work is needed to definitively distinguish this scenario from otherpossibilities.

Hyper Wide Field Imaging of the Local Group Dwarf Irregular Galaxy IC 1613: An Extended Component of Metal-poor Stars