Deep into the structure of the first galaxies: SERRA views
, , , , , , , , and .
(2019)cite arxiv:1905.08254Comment: 22 pages, 14 figures, accepted by MNRAS.

We study the formation and evolution of a sample of Lyman Break Galaxies in the Epoch of Reionization by using high-resolution ($10 \,pc$), cosmological zoom-in simulations part of the SERRA suite. In SERRA, we follow the interstellar medium (ISM) thermo-chemical non-equilibrium evolution, and perform on-the-fly radiative transfer of the interstellar radiation field (ISRF). The simulation outputs are post-processed to compute the emission of far infrared lines (CII, NII, and OIII). At $z=8$, the most massive galaxy, `Freesia', has an age $t_409\,Myr$, stellar mass $M_\star 4.210^9 M_ødot$, and a star formation rate $SFR 11.5\,M_ødotyr^-1$, due to a recent burst. Freesia has two stellar components (A and B) separated by $2.5\, \rm kpc$; other 11 galaxies are found within $56.9 21.6 \, kpc$. The mean ISRF in the Habing band is $G = 7.9\, G_0$ and is spatially uniform; in contrast, the ionisation parameter is $U = 2^+20_-2 10^-3$, and has a patchy distribution peaked at the location of star-forming sites. The resulting ionising escape fraction from Freesia is $f_esc2\%$. While CII emission is extended (radius 1.54 kpc), OIII is concentrated in Freesia-A (0.85 kpc), where the ratio $\Sigma_OIII/\Sigma_CII 10$. As many high-$z$ galaxies, Freesia lies below the local CII-SFR relation. We show that this is the general consequence of a starburst phase (pushing the galaxy above the Kennicutt-Schmidt relation) which disrupts/photodissociates the emitting molecular clouds around star-forming sites. Metallicity has a sub-dominant impact on the amplitude of CII-SFR deviations.
  • @gpkulkarni
This publication has not been reviewed yet.

rating distribution
average user rating0.0 out of 5.0 based on 0 reviews
    Please log in to take part in the discussion (add own reviews or comments).