Equatorial strip sample : a blind Hi survey for gas-rich galaxies

Garcia-Appadoo, Diego Alex 2005. Equatorial strip sample : a blind Hi survey for gas-rich galaxies. PhD Thesis, Cardiff University.

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Abstract

The Equatorial Strip sample comprises 1077 galaxies selected purely by their Hi signature. This is a unique sample which covers a large area of sky, is free from optical selection effects and which has complete, very high quality, optical data (SDSS) for a subsample of 201 galaxies. The combination of the Hi data with optical data allows us to make a comprehensive analysis and study of the properties of Hi selected extragalactic sources and investigate vital global correlations which will help us to improve our understanding of gas-rich and Low Surface Brightness galaxies. The Equatorial Strip runs along the celestial equator from 6 < 8 < +10 and through all R.A.s. The Equatorial Strip sample represents 14% of the whole sky, covering an area of 5738 deg2 and a total volume of 2.76 x 106 Mpc-3. LSB galaxies make up 12% of the sample, however, no high luminosity or high Hi mass LSB galaxies have been found. Consequently, LSB galaxies make up no more than 6% of the high luminosity, gas-rich population, and massive LSB galaxies contribute no more than 13% of the population, at the 95% confidence level. The Bivariate Brightness Distribution and the Luminosity Function for the sample have been calculated and relationships found between surface brightness and optical luminosity, Hi, baryonic and dynamical mass. From these results I find that LSB galaxies contribute 3510 % t the number density of gas-rich galaxies in the Universe but only 72% to the luminosity density. They also contribute 21+6% and 12 3% respectively to the neutral hydrogen (Hi) and baryon density of gas-rich galaxies in the Universe. The Equatorial Strip sample has unveiled many objects not found in optical surveys, ranging from very low surface brightness, very blue galaxies to extremely gas-rich galaxies.

Item Type:	Thesis (PhD)
Status:	Unpublished
Schools:	Physics and Astronomy
Subjects:	Q Science > QB Astronomy Q Science > QC Physics
ISBN:	9781303201523
Date of First Compliant Deposit:	30 March 2016
Last Modified:	10 Oct 2017 15:29
URI:	https://orca.cardiff.ac.uk/id/eprint/55990

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