Radial velocities, dynamics of stars and nebulosities with GAIA and VLT-GIRAFFE

TL;DR

This paper analyzes radial velocities of stars and nebulosities in the Magellanic Clouds using VLT-GIRAFFE data and discusses Gaia RVS methods, revealing bi-modal velocity distributions linked to superbubble expansion.

Contribution

It combines ground-based VLT-GIRAFFE observations with Gaia RVS data to study stellar and nebulosity dynamics, highlighting the bi-modal velocity distribution in the LMC.

Findings

Bi-modal RV distribution for LMC nebulosities.

Expansion of the LMC4 superbubble inferred from RV data.

Preliminary Gaia RVS velocity determination methods.

Abstract

This document is divided in two parts. The first part deals with the radial velocities (RV) distributions for B-type stars and nebulosities observed with the VLT-GIRAFFE in the Large and Small Magellanic Clouds towards the open clusters NGC2004 and NGC330. Thanks to the resolution of GIRAFFE spectra, we found that the RV distribution for the nebulosities in the LMC is bi-modal. This bi-modality can be interpreted, in term of dynamics, by the expansion of the LMC4 superbubble. The second part deals with the GAIA space mission and the determination of the radial velocities by using Radial Velocity Spectrometer (RVS) spectra. The methods to determine the radial velocities are presented as well as preliminary results on simulated RVS spectra.