... environments¹

This presentation is a short summary of my PhD thesis work done at the University of Basel from 1995 to 2000. See references therein. The author will provide an electronic version on request.

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... gas²

the absence of HI gas renders distance determinations with radio telescopes impossible, and optical spectroscopy is mostly too time demanding due to the low luminosity of the objects,except for the closest systems which can be resolved. The only situation where distances to many dwarf galaxies at large distances may be roughly estimated is in the case of dwarfs in galaxy clusters or groups. One can then suppose that most faint objects apparently related to the groups are situated at the same distance as the group or cluster itself

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... sized³

1.2 meter class

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... telescopes⁴

large telescopes are mostly massively overbooked so that one cannot expect getting enough time to complete such a project

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... now⁵

year 2000

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... We⁶

B. Binggeli and myself

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... luminosity⁷

center of dwarf: 30#30, in faint outer parts: 31#31

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... galaxies.⁸

Typically, one constructs a growth curve (GC) for a galaxy by integrating the light from it in concentric circular, or elliptical, apertures of increasing radius. The centers used for the GC are in general defined by the center of ellipses fitted at low surface brightness levels, so as to use the center of the smooth underlying older stellar population

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... curves⁹

first derivative of the growth curve

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... density-morphology¹⁰

or a density-population

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... separately¹¹

The galaxy types considered are subdivided into two categories: an early type class composed of dEs and dS0s, and a late type class composed of dI, Sm and BCD galaxies

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