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arXiv · 1808.01146

Witnessing galaxy assembly at the edge of the reionization epoch

V. D'Odorico·C. Feruglio·A. Ferrara·S. Gallerani·A. Pallottini·S. Carniani·R. Maiolino·S. Cristiani·A. Marconi·E. Piconcelli·F. Fiore
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Abstract

We report the discovery of Serenity-18, a galaxy at z=5.939 for which we could measure the content of molecular gas, M(H_2)~ 5 x10^9 M_sun, traced by the CO(6-5) emission, together with the metal-poor ([Fe/H]=-3.08 +- 0.12, [Si/H]=-2.86 +- 0.14) gas clump/filament which is possibly feeding its growth. The galaxy has an estimated star formation rate of ~100 M_sun yr^{-1}, implying that it is a typical main sequence galaxy at these redshifts. The metal-poor gas is detected through a damped Lyman-alpha absorber (DLA) observed at a spatial separation of 40 kpc and at the same redshift of Serenity-18, along the line of sight to the quasar SDSS J2310+1855 (z_em = 6.0025). The chemical abundances measured for the damped Lyman-alpha system are in very good agreement with those measured for other DLAs discovered at similar redshifts, indicating an enrichment due to massive PopII stars. The galaxy/Damped system we discovered is a direct observational evidence of the assembly of a galaxy at the edge of the reionization epoch.

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V. D'Odorico, C. Feruglio, A. Ferrara, S. Gallerani, A. Pallottini, S. Carniani, R. Maiolino, S. Cristiani, A. Marconi, E. Piconcelli, F. Fiore. 2018-08-03. Witnessing galaxy assembly at the edge of the reionization epoch. https://doi.org/10.3847/2041-8213/aad7b7

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