Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.atnf.csiro.au/people/Angel.Lopez-Sanchez/proceedings/SEA_Toledo_2002_lopez-sanchez.ps Дата изменения: Sun Feb 3 04:13:52 2008 Дата индексирования: Mon Apr 14 08:42:18 2008 Кодировка: Поисковые слова: m 106

CAN INTERACTIONS BE THE MAIN
STAR FORMATION MECHANISM IN
WOLF-RAYET GALAXIES?

Angel R. Lopez-Sanchez & Cesar Esteban
Instituto de Astrofsica de Canarias
angelrls@ll.iac.es, cel@ll.iac.es
ABSTRACT
Interaction can be an important mechanism that triggers star for-
mation in Wolf-Rayet galaxies, specially in dwarf ones when they are
observed with enough resolution and sensitivity. Some of them present
tidal tails connecting small stellar aggregates. We have analysed deep
CCD imagery and intermediate resolution optical spectroscopy of four
Wolf-Rayet galaxies and surrounding objects in order to study their
inter-relation. We have studied the morphology of these systems, the
kinematics and the chemical composition of the ionized gas.
The study of the O/H ratio of Mrk 1087 suggests that it is experi-
encing a strong star formation event due to the interaction with at least
two external galaxies. In Haro 15 (Mrk 960) we nd two bright star-
forming zones in its inner part (the nucleus and an ESE companion) and
other knot at the NE. The O/H and the [NII]/H ratios suggest that
the ESE companion could be an external galaxy. Mrk 1199 is a Sb
galaxy interacting with a dwarf object at the NE. We nd a dierence
between the abundances and we think that they are dierent systems.
Tol 9 (ESO 436-42) is a suspected WR galaxy with a dwarf companion
galaxy. Both objects seem to be interacting because there is a bridge of
matter connecting them. Only the main body shows emission spectra.
Table 1. Absolute magnitudes in V band and O/H ratio for our Wolf-Rayet galaxies
and their companions (c.). O/H ratio is 12+log(O/H).
Object Mrk1087 c. Haro15 ESE c. NE c. Mrk1199 c. Tol9
MV -21.9 -18.2 -20.87 -20.25 -17.95 -20.85 -17.9 -18.85
O/H 8.70 8.30 8.50 8.17 8.30 9.05 8.55 8.61
1