The dust attenuation law and ISM properties of galaxies at the Epoch of Reionization
Vladan Markov (Scuola Normale Superiore di Pisa)
During The Epoch of Reionization (EoR), the first galaxies played a key role in the complete reionization of the Universe by z∼6 and in the metal enrichment of the intergalactic medium. Constraining the properties of early galaxies is fundamental in our understanding of galaxy evolution. Standard approach in characterizing the galaxy properties is through the spectral energy distribution (SED) fitting method with a priori assumption on the dust attenuation law (e.g. ”Calzetti” and SMC). However, the dust properties of high-z sources are not well described by the reddening curves derived for local sources. Constraining the dust attenuation law is important for characterizing the dust properties and the dust production mechanisms, but also the global properties of galaxies in the early Universe.
I will present a new tool, based on the SED fitting method, that allows us to simultaneously characterize the dust attenuation properties along with the global parameters of galaxies, without any a priori assumption on the dust law. The advantage of using this robust model, is its capability to recover the dust attenuation properties reddened by any well-known,or potential new dust curve. We test our tool on the synthetic spectra, and apply it on the James Webb Space Telescope (JWST) observations of a sample of star-forming galaxies at the EoR. Our tool and the new JWST data will provide means to constrain the dust properties of a large sample of galaxies at the EoR. I will also discuss how we combined the emission of two carbon lines, [CIII] λ1909 and [CII]158μm (which trace different phases of the ISM), in order to constrain the ISM conditions (gas density, metallicity and ”burstiness”) of high-z star-forming galaxies (Markov et al. 2022).
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