Astron. Astrophys. Suppl. Ser. 142, 399-416
J. Vennik1 - U. Hopp2 - C.C. Popescu3,4
Send offprint request: J. Vennik
1 - Tartu Observatory, 61602 Tõravere, Tartumaa, Estonia
e-mail: vennik@aai.ee
2 -
Universitätssternwarte München, Scheiner Str. 1,
D-81679 München, Germany
e-mail: hopp@usm.uni-muenchen.de
3 -
Max Planck Institut für Kernphysik, Saupfercheckweg 1, D-69117
Heidelberg, Germany
e-mail: Cristina.Popescu@mpi-hd.mpg.de
4 -
The Astronomical Institute of the Romanian Academy, Str. Cutitul de
Argint 5, 75212 Bucharest, Romania
Received November 12; accepted December 22, 1999
We performed the SB profile decomposition by means of disentangling the
underlying stellar disk and the excess light above the exponential disk.
We classified the profiles into 5 types: pure disk profiles (21% of studied
139 ELGs); profiles that show both disk and bulge/nucleus/H II knot components
(37%); profiles that have central light depression (13%); non-disky
(concave) profiles (7%); and almost unresolved (quasi-stellar) images and
stellar SB profiles (22%).
Popescu et al. ([1997]) found that most of the studied ELGs follow the
spatial distribution of normal galaxies from the CfA
Redshift Survey. 15 ELGs and 1 non-ELG were classified as being well
isolated and are distributed within nearby (
0.033) voids.
We found that these isolated ELGs are almost all dwarf galaxies
with
-18.4 < M B < -12.7,
they show similar luminosities and colours as the
nearby non-isolated ELGs. For 8 of 15 isolated ELGs an underlying LSBG
has been detected. The underlying disks of isolated ELGs tend to be
larger and of lower SB, than the disks of non-isolated ELGs (of
the same total blue flux).
Key words: galaxies: photometry -- galaxies: fundamental parameters -- galaxies: structure; cosmology: large scale structure of Universe
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