The Obelisk dust model: Using Rascas to analyze dust during the Epoch of Reionization

Bor, Pelle van de (2023) The Obelisk dust model: Using Rascas to analyze dust during the Epoch of Reionization. Master's Thesis / Essay, Astronomy.

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Abstract

Recent high-redshift detections of dust with ALMA and JWST have provided ques- tions on the amount of dust in the early Universe. Dust may influence reionization by absorbing ionizing photons, but this effect is difficult to measure. To study the effect of dust on spectral properties, mock spectra are generated from the Obelisk simula- tion, which introduced a unique system of tracing dust for cosmological simulations. This system follows dust creation and destruction on a subgrid level, decoupling dust from gas. This thesis focuses on comparing this new model to existing models of dust attenuation (SMC, LMC, and BARE-GR-S). I generated mock spectra of a sample of 554 halos in the Obelisk simulation using the Rascas code at z = 6. This is done for an angle-averaged view and 12 viewing directions for each halo. From the spectra, the UV continuum slopes are found to be in line with literature values. The 2175 ̊A absorption feature is present in the Obelisk dust model. Using a Drude profile to model this feature, it is found that this does not influence the continuum slope measurement. The equivalent width of this feature is found to be correlated with the dust attenuation at 1500 ̊A. To study the influence of dust on reionization, ionizing escape fractions are calcu- lated. Using the directional spectra, it is shown that most of the ionizing radiation leaks from single directions with high escape fractions. The predicted escape fraction using the Obelisk model is compared to du

Item Type:	Thesis (Master's Thesis / Essay)
Supervisor name:	Dayal, P. and Mauerhofer, V.
Degree programme:	Astronomy
Thesis type:	Master's Thesis / Essay
Language:	English
Date Deposited:	19 Jul 2023 06:48
Last Modified:	19 Jul 2023 06:48
URI:	https://fse.studenttheses.ub.rug.nl/id/eprint/30740

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