Gemini Preprint #58


Galaxy Surface Photometry

B. Milvang-Jensen
University of Nottingham, University Park, NG7 2RD Nottingham, UK

I. Jørgensen
Gemini Observatory Northern Operations Center, 670 N. A'ohoku Place, Hilo HI 96720

Abstract.

We describe galaxy surface photometry based on fitting ellipses to the isophotes of the galaxies. Example galaxies with different isophotal shapes are used to illustrate the process, including how the deviations from elliptical isophotes are quantified using Fourier expansions. We show how the definitions of the Fourier coefficients employed by different authors are linked.

As examples of applications of surface photometry we discuss the determination of the relative disk luminosities and the inclinations for E and S0 galaxies. We also describe the color-magnitude and color-color relations. When using both near-infrared and optical photometry, the age-metallicity degeneracy may be broken. Finally we discuss the Fundamental Plane where surface photometry is combined with spectroscopy. It is shown how the FP can be used as a sensitive tool to study galaxy evolution.

To appear in Baltic Astronomy, Vol. 8, no. 4.

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Ruth A. Kneale / web@gemini.edu / March 28, 2000