2024/07/10 by Itsuki Ogami, Ogami, Itsuki, Yutaka Komiyama +19
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.2407.07481
openalex publication_date 2024/07/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report the detection of a dwarf satellite candidate (Triangulum IV: Tri IV) of the Triangulum galaxy (M33) using the deep imaging of Subaru/Hyper Suprime-Cam (HSC). From the apparent magnitude of the horizontal branch in Tri IV, the heliocentric distance of Tri IV is estimated to be 932+49-43 kpc, indicating that Tri IV is located at the distance of 75+48-40 kpc from the M33 center. This means that Tri IV is the probable satellite of M33, because its distance from M33 is within the virial radius of M33. We also estimate its surface brightness of μ\it V = 29.72+0.10-0.10 mag arcsec-2, and half-light radius of rh = 1749+523-425 pc, suggesting that Tri IV is an ultra-diffuse galaxy or dynamically heated galaxy. The surface brightness of Tri IV is too low to be detected in the previous survey, so this detection suggests that much fainter satellites may be present in the outskirts of M33.