| |
 |
| Paper: |
Mapping Extremely Low Metallicity Galaxies to z ∼ 1 |
| Volume: |
399, Panoramic Views of Galaxy Formation and Evolution |
| Page: |
235 |
| Authors: |
Kakazu, Y.; Cowie, L.L.; Hu, E.M. |
| Abstract: |
We report on systematic wide-field studies of ultra-strong emission line galaxies (USELs; EW(Hβ) ≥ 30Å) selected using two narrowband filters (NB816 and NB912) with Subaru/Suprime-Cam. The majority of USELs are galaxies at intermediate redshift (z < 1), which are often considered as contaminants in searches for z >> 5 Lyα galaxies. In the current presentation, however, we show that USELs produce significant amounts of star formation at 0 < z < 1. Furthermore, Keck/DEIMOS spectra of the majority of USELs exhibit the temperature sensitive [OIII] auroral lines and about a dozen have oxygen abundance satisfying the criteria of eXtremely Metal Poor Galaxies (XMPGs). Our high yield rate of XMPGs suggests that the narrowband method is a powerful way to find such very low-metallicity populations at z < 1, which up till now have been found only in nearby (z < 0.03), and typically dwarf galaxies. Intriguingly, the lowest metallicity measured in our sample is close to the minimum metallicity found in local galaxies [e.g., I Zw 18; SBS0335-052W]. The luminosities, metallicities, and star formation rates of these strong emitters are consistent with their being start-up intermediate mass galaxies, which will evolve into more normal galaxies and suggest that galaxies are still forming in relatively chemically pristine sites at z < 1. |
|
|
|
|
|
