Exploring the interstellar media of optically compact dwarf galaxies

Abstract

We present new Very Large Array H I spectral line, archival Sloan Digital Sky Survey, and archival Spitzer Space Telescope imaging of eight star-forming blue compact dwarf galaxies that were selected to be optically compact (optical radii <1 kpc). These systems have faint blue absolute magnitudes (M B ≳ -17), ongoing star formation (based on emission-line selection by the Hα or [O III] lines), and are nearby (mean velocity = 3315 km s-1 ≃ 45 Mpc). One galaxy in the sample, ADBS 113845+2008, is found to have an H I halo that extends 58 r-band scale lengths from its stellar body. In contrast, the rest of the sample galaxies have H I radii to optical-scale-length ratios ranging from 9.3 to 26. The size of the H I disk in the "giant disk" dwarf galaxy ADBS 113845+2008 appears to be unusual as compared with similarly compact stellar populations. © 2013. The American Astronomical Society. All rights reserved.