October 24-28, 2016

Abstract

Analogs of primeval galaxies at z~3: Studying the early build-up and chemical enrichment of young galaxies before the arrival of JWST

Ricardo Amorin (INAF-Osservatorio Astronomico di Roma)

The VUDS Collaboration

The physical mechanisms governing the birth and early evolution of galaxy's life are still hidden to our exploration. Deep observations have revealed that young luminous galaxies at z>6 have more extreme properties compared to typical star-forming galaxies studied at lower redshift, namely, different emission line properties, higher specific star formation rates, lower masses, and smaller sizes. However, until the arrival of the James Webb Space Telescope, detailed spectroscopic studies of their abundances and ionization properties are unfeasible, strongly limiting our understanding of the physics driving early galaxy build-up and chemical enrichment. In this talk I will present the discovery of a rare population of small, sub-L*(z=3) young galaxies at redshift z~2.5-3.5 that exhibit all the rest-frame properties expected from primeval galaxies in the first billion year of cosmic time. Our sample is selected by their strong nebular UV emission lines (including CIII]1908, OIII]1663 and, in some cases, CIV1550 and HeII1640) from thousands of targets in the VIMOS Ultra Deep Survey (VUDS). They are extremely compact, low-mass galaxies showing hard radiation fields and low metal abundances, which suggest that they are caught in their first epoch of assembling and chemical enrichment. I will discuss their rest-frame spectrophotometric properties, highlighting their use as a benchmark for comparison studies with z>6 galaxies, which will be routinely discovered, e.g., with JWST-NIRSpec.

Talk