Blue Compact Galaxies at Redshifts Z=0.2-1.3

We study the nature of faint blue compact galaxies (BCGs) at redshifts z ∼ 0.2 - 1.3 using Keck and HST. Despite being very luminous (L_B ∼ L^*), most distant BCGs have masses M ∼ 10¹⁰M_⊙, i.e., they are dwarf stellar systems. The majority of these galaxies have colors, sizes, surface brightnesses, luminosities, velocity widths, excitations, star formation rates (SFR), and mass-to-light ratios characteristic of the most luminous nearby HII galaxies. The more massive BCGs form a more heterogeneous class of evolved starburst, similar to local disk starburst galaxies. Without additional star formation, HII-like BCGs will most likely fade to resemble today's spheroidal galaxies such as NGC 205. This revised version was published online in July 2006 with corrections to the Cover Date.