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Probing the ISM properties of first galaxies through [CII] and CO line emission
Livia Vallini (Leiden University)
Thursday 21/02/2019 @ 11:30, Sala IV piano Battiferro
The advent of ALMA, soon to be complemented by JWST and SPICA, has started to revolutionise the study of the ISM in the first galaxies. In the last few years, ALMA has enabled the first handful of detections of [CII] 158um, [OIII] 88um, and CO line emission in normal (SFR < 100 Msun/yr) galaxies at z > 6, opening up a window on the various gas phases of the ISM (molecular, neutral, ionized) in galaxies during the EoR. In this talk I will present a theoretical model that allows us to predict FIR line emission from early galaxies and to shed light on the role of stellar feedback and turbulence in modulating the line emission. To this aim, we coupled state-of-the-art, high-resolution (30 pc), cosmological simulation of a main sequence galaxy at z~6 with sub-grid models that simultaneously account for the radiative transfer, clumpy structure, and photoevaporation feedback in the neutral diffuse and molecular gas. This allows us to compute the luminosity of [CII], [OIII], and CO rotational lines, and to obtain high-resolution emission maps of our simulated galaxy. I will focus also on the predicted shape of the CO Spectral Line Energy Distribution (CO SLED), and on the expected value of the CO-to-H2 conversion factor in galaxies during the Epoch of Reionization. I will also discuss the impact of X-ray photons on the CO SLED.