Blueberry galaxies up to 200 Mpc and their optical/infrared properties

K. Kouroumpatzakis, A. Zezas, A. Borkar, E. Kyritsis, P. G. Boorman, C. Daoutis, B. Adamcová, R. Grossová

Published 2024-05-06Version 1

Dwarf highly star-forming galaxies (SFGs) dominated the early Universe and are considered the main driver of its reionization. Direct observations of these very distant galaxies are limited mainly to rest-frame ultraviolet and visible wavelengths, and as a result, some of their properties are out of reach. Therefore, the study of their local analogs, the Green Pea (GP) and Blueberry (BB) galaxies is still of paramount importance. This work aims to expand the number of known BBs to smaller distances and the south equatorial sky. In addition to the already known, this new sample of BBs allows for a statistically significant study of their properties probed by visible and infrared (IR) light. We utilize HECATE, a catalog of galaxies up to 200 Mpc, which provides optical/IR photometry and characterization of the sources. We adopt the Pan-STARSS and SDSS optical photometries, and MPA-JHU analysis for sources having spectroscopic observations. Benefited by the multiwavelength coverage, we perform spectral energy distribution fitting to provide homogeneous star-formation rates and stellar masses. This work has identified 48 BBs out of which 40 are new. The nearest BB lies at 19 Mpc while 14 BBs are in the south equatorial sky. The BBs tend to be extremely IR red in both WISE W1-W2 and W2-W3 colors, located in different positions in this diagram compared to typical SFGs. Overall, dwarf SFGs with higher specific star-formation rates tend to have redder IR colors. Although GPs and BBs share many similarities, the latter are the most intensively star-forming sources of the local Universe among dwarf galaxies. Overall BBs are intrinsically bluer in visible light, redder in the IR, less massive, have higher specific star-formation rates and equivalent widths, lower metallicities, and have the most strongly ionized interstellar medium compared to typical SFGs and GPs.