VLT L-band mapping of the Galactic Center IRS 3-IRS 13 region Evidence for new Wolf-Rayet type stars

TL;DR

This study uses VLT L-band spectroscopy to map the Galactic Center region, revealing evidence for new Wolf-Rayet stars and providing insights into the local interstellar medium and star dynamics.

Contribution

First spectroscopic data cube of the Galactic Center in L-band, identifying potential new Wolf-Rayet stars and analyzing interstellar medium properties.

Findings

Identification of three candidate Wolf-Rayet stars with broad emission lines.

Maps of water ice and hydrocarbon absorption reveal local ISM features.

Evidence of turbulence and complex medium structure in the Galactic Center.

Abstract

This paper presents L-band ISAAC and NAOS/CONICA (VLT) spectroscopic observations of the IRS~3-IRS~13 Galactic Center region. The ISAAC data allowed us to build the first spectroscopic data cube of the region in the L-band domain corrected for the foreground extinction. Maps of the water ice and hydrocarbon absorption line strength were then derived. These maps are important diagnostics of the interstellar and circumstellar medium (resp. ISM and CSM). They support our previous results that the absorption features are most probably occuring in the local Galactic center medium and can be associated with the individual sources. Moreover, turbulence seems to affect the studied region of the minispiral which appears like a mixture of a dense and diffuse medium. The Br alpha and Pf gamma emission line maps allowed us to find three sources with broad lines corresponding to a FWHM deconvolved line width of about 1100 km/s and moving towards us with a radial velocity of about -300km/s. These sources are most probably new Wolf-Rayet type stars located in projection to the north and west of IRS 3. Their derived radial velocities and proper motions show that only two of them might belong to the two rotating disks of young stars reported by Genzel et al. (2003) and Levin & Beloborodov (2003)...