Evidence for ubiquitous high-equivalent-width nebular emission in z∼ 7 galaxies: toward a clean measurement of the specific star-formation rate using a sample of... Academic Article uri icon

abstract

  • Growing observational evidence indicates that nebular line emission has a significant impact on the rest-frame optical fluxes of z~ 5-7 galaxies. This line emission makes z~ 5-7 galaxies appear more massive, with lower specific star-formation rates (sSFRs). However, corrections for this line emission have been difficult to perform reliably because of huge uncertainties on the strength of such emission at z gsim 5.5. In this paper, we present the most direct observational evidence thus far for ubiquitous high-equivalent-width (EW)[O III]+ Hβ line emission in Lyman-break galaxies at z~ 7, and we present a strategy for an improved measurement of the sSFR at z~ 7. We accomplish this through the selection of bright galaxies in the narrow redshift window z~ 6.6-7.0 where the Spitzer/Infrared Array Camera (IRAC) 4.5 μm flux provides a clean measurement of the stellar continuum light …

authors

publication date

  • March 4, 2014