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تسجيل مستخدم جديدSED Analysis of 47 Spectroscopically Confirmed Galaxies at $zsimeq6$ to Constrain Possible Relationships between UV Slope, Dust attenuation, and Escape Fraction
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Junehyoung Jeon
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The reionization of the Universe is thought to have been completed by redshifts $zsimeq5.5$. Observations of galaxies in the Subaru Deep Field (SDF) found more than 100 galaxies at $zsimeq6$, many spectroscopically confirmed through follow-up observations. Among a sample of such 67 galaxies, seven galaxies were examined previously, and six showed steep UV-Continuum slopes ($beta$) between $-3.4<beta<-2.6$, indicating young stellar populations. Using the CIGALE package, we model the SEDs of 47 SDF galaxies with Subaru WFCAM K-band data of the seven galaxies studied previously, using a large model parameter space. The seven blue-$beta$ galaxies are compared to the other 40 SDF galaxies to trace any differences or possible relationships in e.g. the model-implied SED age, dust extinction, and the Lyman continuum (LyC) escape fraction $f_{esc}$. We found that the average implied $f_{esc}$ value is $sim42%$, exceeding the minimum for galaxies to finish reionization at $zsimeq6$. Furthermore, we found slight trends between the CIGALE UV-slope, $f_{esc}$, and E(B-V) values: for a given CIGALE E(B-V) value, the implied $beta$ values are steeper than at $z=0$. Lower implied CIGALE $f_{esc}$ values appear to be associated with bluer $beta$ and lower E(B-V), but the trends between the parameters are weak. This suggests that LyC could have escaped through holes in the surrounding the ISM produced by outflows from supernovae and/or weak AGN, with sufficiently wide opening angles for on average $42%$ of the LyC to escape. Further IR spectroscopic observations with the emph{James Webb Space Telescope} will be needed to constrain this possibility.
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