Vendredi 11 Octobre 2002, à 14h, Paris, 77 avenue Denfert Rochereau, 14h
77 avenue Denfert Rochereau, Paris 14
Salle de l'Atelier, Observatoire de Paris
Heating and ionization in the Galactic Center
Nemesio RODRIGUEZ FERNANDEZ
Observatoire de Paris/LERMA
Résumé :
Up to 10 % of the neutral gas of the Milky Way is concentrated in the
central 500 pc of the Galaxy.
In spite of the high gas surface density in the Galactic center (GC),
the star formation rate is 10 times lower that that in the disk of the
Galaxy. This is probably due to the particular conditions of the gas.
The molecular clouds in the Galactic center are more turbulent, denser,
and hotter than the clouds of the disk. In particular, the high temperatures
are present over large regions where the dust is cold and apparently
without associated ionized gas.
To study the physical conditions of the interstellar medium in the GC, and
the heating of the molecular gas, we have observed a sample
of clouds distributed all along the Galactic center.
I will present ISO LWS/SWS observations of H2 pure rotational lines and
fine-structure lines of several ions.
With these observations we have been able to determine for the first time
the total amount of warm molecular gas in the GC clouds. In addition,
they have revealed the presence of a previously unknown ionized gas
component. I will discuss how this findings give us further insight on
the heating and the ionization of the GC interstellar medium.
