2015/04/02 by Jin Koda, Masafumi Yagi, Yutaka Komiyama +12
Physics and Astronomy · #Absolute magnitude #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Dwarf galaxy #Galaxies: Formation, Evolution, Phenomena #Galaxy #Interacting galaxy #Irregular galaxy #Local Group #Luminosity #Physics #Spiral galaxy #Star formation #Stars #Stellar population #Stellar, planetary, and galactic studies #Surface brightness #astro-ph.CO #astro-ph.GA
paper · pdf · doi:10.1088/2041-8205/802/2/l24
Published in ApJL (ApJ, 802, L24). 7 pages, 4 figures
arxiv created 2015/04/02 · openalex publication_date 2015/04/02 · arxiv updated 2015/06/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We report the discovery of a new dwarf galaxy (NGC 6503-d1) during the Subaru extended ultraviolet disk survey. It is a likely companion of the spiral galaxy NGC 6503. The resolved images, in the B , V , R , i , and H α bands, show an irregular appearance due to bright stars with underlying, smooth and unresolved stellar emission. It is classified as the transition type (dwarf irregular (dIrr)/dwarf spheroidal (dSph)) between the dIrr and dSph types. Its structural properties are similar to those of the dwarfs in the Local Group, with an absolute magnitude half-light radius , and central surface brightness . Despite the low stellar surface brightness environment, one H ii region was detected, though its H α luminosity is low, indicating an absence of any appreciable O-stars at the current epoch. The presence of multiple stellar populations is indicated by the color–magnitude diagram of ∼300 bright resolved stars and the total colors of the dwarf, with the majority of its total stellar mass in an old stellar population.