Issue |
Astron. Astrophys. Suppl. Ser.
Volume 142, Number 3, March II 2000
|
|
---|---|---|
Page(s) | 399 - 416 | |
DOI | https://doi.org/10.1051/aas:2000160 | |
Published online | 15 March 2000 |
Surface photometry of emission-line galaxies in low density regions *
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. Cuţitul de Argint 5, 75212 Bucharest, Romania
Send offprint request to: J. Vennik
Received:
12
November
1999
Accepted:
22
December
1999
Detailed B and R surface photometry is performed for 139 faint emission-line
galaxies (ELGs) and for 2 non-ELGs.
They are a subsample of the ELG sample selected by
Popescu et al. (1996, 1998) towards four nearby voids. We derived the isophotal
and integral photometric parameters and radial surface brightness (SB)
profiles.
Our sample consists mostly of low luminosity
(), small
linear size (
= 6.0 kpc)
(H0 = 75 km s-1 Mpc-1)
and blue (
= 0.93) galaxies.
About 83% of the studied ELGs belong to
the class of Blue Compact Galaxies (BCGs); others are luminous
Starburst Nucleus Galaxies (SBNs) and a few interacting pairs.
72% of the ELGs possess a single dominant HII region, while the remaining
28% show multiple knots.
Furthermore 71% of the ELGs show regular outer isophotes, and the
remaining 29% reveal disturbed outer morphologies.
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/HII 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
,
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
© European Southern Observatory (ESO), 2000