A. Laval

Fabry-perot Hα-interferometric observations of some HII regions. I. SH2-152 and SH2-153

Hα-interferometric observations of the HII-regions Sh2-152 and Sh2-153 are carried out with a high resolution (1 pixel=2.13×2.13 arcsec). They confirm the results on the structure of those formations obtained earlier. Individual radial velocities determined in different points for each of these HII-regions show that the inner motions of ionized matter relative to the exciting stars are, in general, of expanding character. It gives ground to assume that in both these star forming regions the dissipation of matter takes place.

A kinematical catalogue of HII regions and superbubbles in the LMC

We report the results of a kinematic Hα survey of the Large Magellanic Cloud (LMC) in the form of a kinematic and photometric catalogue of 210 HII regions, the radial velocity field of the ionized hydrogen in this galaxy, and the LMC Rotation Curve obtained from the velocity field. These data aim at understanding the LMC HII regions, bubbles and superbubbles in a global (galactic) scale so that we could have a 3D view and separate the rotation due to gravitational potential from other motions such as expansions.

3D Observations of the nebula N30 in the LMC

N30 is a 80×330 pc nebula, seen in projection to the North of the LMC. At the position of the nebula, the neutral HI gas is distributed within two layers, with respective heliocentric velocities of 303 km s −1 for the major disk component, and 285 km s −1 for the low-velocity component (Luks & Rohlf 1992). The respective positions of the HI components along the line of sight are not known, nor is the distance between the HI layers, nor their thickness. N30 has been observed with the “survey Hα” equipment of the Observatoire de Marseille (see Rosado et al, and Marcelin et al.,this meeting), giving a 38’ square field (spatial resolution of 9“×9”) and using two scanning Fabry-Perot interferometers, the first one having a spectral sampling step of 15.7 km s −1 , and the second one of 4.8 km s −1 . No splitting of the line profile is visible, excluding large inner motions. The main emissions measured in N30 and also in all its 8 nearby bright and faint nebulae have heliocentric velocities in the range 302-315 km s −1 . Such a velocity shows that all the nebulae are situated inside the HI disk component, following their exciting stars.

French-Armenian scientific cooperation on study of some HII-regions with cigale

The results of the scientific cooperation between astronomers of the Byurakan and Marseille observatories on the study of diffuse matter in the Galaxy are presented.Hα-emission is discovered in the direction of h and x Per. Fabry-Perot observations of three HII-regions, Sh2-152, 153, and 106, show the expansion of the diffuse matter relative to the exciting stars. In the Sh2-106 region a probable jet is found. It is shown that in star forming regions the diffuse matter takes part in expansion motions together with stars.

Hα Survey of the Milky Way and Magellanic Clouds

In 1990 we began an Hα survey of the Milky Way and the Magellanic clouds at ESO La Silla with a 36 cm telescope. The main goal of this survey is to study in detail complexes of HII regions, as well as the global spiral structure of our Galaxy.