IAA authors:
Masegosa J.;Márquez I.;Merlino S.
Authors:
Kniazcv A.Y., Pustilnik S.A., Masegosa J., Márquez I., Ugryumov A.V., Martin J.-M., Izotov Y.I., Engels D., Brosch N., Hopp U., Merlino S., Lipovetsky V.A.
Journal:
Astronomy and Astrophysics
Abstract:
We present the results of spectrophotometry and BV R CCD photometry, as well as integrated HI radio measurements of a new blue compact galaxy (BCG) HS 0822+3542 with extremely low oxygen abundance: 12+log(O/H) = 7.35, or 1/36 of solar value. The galaxy is the third most metal-deficient BCG after I Zw 18 and SBS 0335-052. Its very high mass fraction of gas (≈ 95% of all visible mass) and blue colours of underlying nebulosity are also similar to those of SBS 0335-052. This suggests that HS 0822+3542 is one of the nearest and dimmest galaxies experiencing a recently-started first star formation (SF) episode. Its properties imply that for such galaxies there is a linear scaling of the main parameters, at least for the baryon mass range (0.3-20)×108 M⊙. The total mass estimate indicates that the galaxy is dynamically dominated by a dark matter (DM) halo, which itself is one of the least massive for galaxies.
Keywords:
Galaxies: abundances; Galaxies: fundamental parameters; Galaxies: individual: Hs 0822+3542; Galaxies: photometry; Galaxies: star-burst