Green Peas in the Southern Sky: Broadband Color Selection and Spectroscopic Follow-up

초록

We present a systematic search for 1696 green pea (GP) galaxy candidates in the southern hemisphere selected from the Dark Energy Survey Data Release 2 and provide preliminary results from spectroscopic follow-up observations of 26 targets chosen among them. Our selection criteria include the colors in the gri bands and compact morphology in the color-composite images. The multiwavelength spectral energy distribution fitting shows that the selected GP candidates exhibit star formation rates up to several tens of M circle dot yr-1. With the mean stellar mass of logM*/M circle dot=8.6 , GP candidates are located at roughly 1 dex above the main sequence of star-forming galaxies at z similar to 0.3. Spectroscopic follow-up observations of the GP candidates with Gemini/Gemini Multi-Object Spectrograph are underway. All 26 targets are spectroscopically confirmed to be at z = 0.3-0.41 and have an [O iii] equivalent width larger than 85 & Aring;, classified to be starbursts with low-to-moderate dust attenuation. These confirmed GPs show a lower metallicity offset from the mass-metallicity relation of local star-forming galaxies, indicating that GPs are less chemically evolved systems at their early stage of evolution.

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