Identification of young star-forming galaxies at redshifts z=0-7

Tang, F (2017) Identification of young star-forming galaxies at redshifts z=0-7. Bachelor's Thesis, Astronomy.

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Abstract

In this work we investigate the presence of young star-forming galaxies at redshifts z=0-7 using spectral energy distribution (SED) fitting. We use photometry in the CANDELS GOODS-South field, the photometric redshift code Le PHARE and galaxy SED models from the Yggdrasil package. The Yggdrasil templates have inferior performance than traditional galaxy models in estimating the redshifts of all galaxies in a flux-limited catalogue like CANDELS GOODS-S. Nevertheless, the availability of young galaxy templates with full incorporation of nebular emission in Yggdrasil is crucial to identify young galaxies with these characteristics at different redshifts. Among the galaxies in our sample with good redshift recovery, we identify 11.6% of them to be young and star-forming. Moreover, the percentage of young star-forming galaxies decreases with increasing redshift. We explore the possibility that this decrease is due to a degeneracy in the SED fitting, which may be caused by a decline in the signal-to-noise ratio of the photometry in some bands. Simulations suggests that our criterion for securely identifying young star-forming galaxies is robust.

Item Type:	Thesis (Bachelor's Thesis)
Degree programme:	Astronomy
Thesis type:	Bachelor's Thesis
Language:	English
Date Deposited:	15 Feb 2018 08:29
Last Modified:	15 Feb 2018 08:29
URI:	https://fse.studenttheses.ub.rug.nl/id/eprint/15423

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