Ia Kochiashvili – Niels Bohr Institute - University of Copenhagen

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Niels Bohr Institute > Research > PhD theses 2016 > 2016 > Ia Kochiashvili

 

Ia KochiashviliIa Kochiashvili

A thesis submitted October 10, 2016 for the degree of Doctor of Philosophy and defended May 11, 2016.

The PhD School of Science
Faculty of Science, Niels Bohr Institute, Dark Cosmology Centre, University of Copenhagen, Denmark

Supervisor:
Prof. Johan P. U. Fynbo

Opponents:
Prof. Anja C. Andersen
Prof. Simona Mei
Prof. Páll Jakobsson

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Abstract

High redshift Lyman-α hunt Galaxies as precious forged jewels

Galaxy formation and evolution has been intensively studied in the past two decades. Results and discoveries revolutionized the field and we now have much better understanding of how these huge conglomerates of baryonic and dark matter evolve.

In the framework of two di fferent projects, which constitute the backbone of this thesis, I investigated the nature of almost 100 emission-line galaxies selected with the narrow-band selection method. These candidates can be: galaxies with H α emission lines at redshift z ∼ 0.6, [Oiii]/Hβ emission-line galaxies at redshift z ∼ 1.15 and [Oii] emitters at z ∼ 1.85.

I used the near-infrared data from NB1060, Y and J filters to perform colour-colour and colour-magnitude selections. With the broad-band data from CANDELS catalogue, I performed SED fitting and derived photometric redshifts and other physical properties for the candidate emission-line galaxies. Significant differences between the two selection methods have been found. The colour-colour selection method, tends to pick galaxies with high colour excess and can leave some strong emission-line candidates with relatively lower colour excess out of the sample. The populations of selected galaxies can also be very biased. The colour-magnitude selection method picks not only “normal” galaxies, but also starburst ones.

More of the abstract in the thesis.

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