Confirmation of Small Dynamical and Stellar Masses for Extreme Emission Line Galaxies at z ~ 2
Bell, Eric F.; Grogin, Norman A.; Kocevski, Dale D.; Koekemoer, Anton M.; Trump, Jonathan R.; Weiner, Benjamin J.; Maseda, Michael V.; Franx, Marijn; van Dokkum, Pieter; van der Wel, Arjen; Pacifici, Camilla; Momcheva, Ivelina; Rix, Hans-Walter; Patel, Shannon G.; Marchesini, Danilo; Nelson, Erica J.; Whitaker, Katherine E.; Skelton, Rosalind E.; Fumagalli, Mattia; Brammer, Gabriel B.; Lundgren, Britt F.; Wuyts, Stijn; Straughn, Amber N.; da Cunha, Elisabete
Germany, South Korea, United States, Netherlands, South Africa
Abstract
Spectroscopic observations from the Large Binocular Telescope and the Very Large Telescope reveal kinematically narrow lines (~50 km s-1) for a sample of 14 extreme emission line galaxies at redshifts 1.4 < z < 2.3. These measurements imply that the total dynamical masses of these systems are low (lsim 3 × 109 M ⊙). Their large [O III] λ5007 equivalent widths (500-1100 Å) and faint blue continuum emission imply young ages of 10-100 Myr and stellar masses of 108-109 M ⊙, confirming the presence of a violent starburst. The dynamical masses represent the first such determinations for low-mass galaxies at z > 1. The stellar mass formed in this vigorous starburst phase represents a large fraction of the total (dynamical) mass, without a significantly massive underlying population of older stars. The occurrence of such intense events in shallow potentials strongly suggests that supernova-driven winds must be of critical importance in the subsequent evolution of these systems.