• Morris, Patrick W.
• Van Dyk, Schuyler D.
• Hadfield, Lucy
• Smith, J. D. T.

Abstract

Massive stars strongly influence galaxy evolution, including that of our own. Stars with Minit ≳ 20 M_☉ evolve to become Wolf-Rayet (WR) stars. WRs are excellent markers and chronometers of very recent star formation and probes of the IMF in galaxies. Galactic optical line surveys for WRs are complete to B ≲ 14 mag;yet the number is low by 4-10× relative to Galaxy models: Many WRs must be obscured by the high visual extinction in the Plane. However, in the infrared (IR), extinction is far lower (e.g., A_K/A_V ~ 10%), greatly enhancing our chances of detecting ``hidden'' WRs. We have characterized the known WRs in the near-IR continuum and are currently working to characterize them further in the mid-IR: Using the near-IR all-sky 2MASS in conjunction with the mid-IR Spitzer GLIMPSE Legacy survey of the Plane (which should straightforwardly reveal WRs still associated with their natal molecular clouds), we are selecting candidate WRs across large spans of the Plane. We propose here the natural extension of this work, i.e., spectroscopic candidate confirmation in both the optical and near-IR which are accessible in 2006A from CTIO. Both optical and near-IR spectra are necessary to fully characterize any newly discovered WRs. We therefore hope to facilitate a more complete determination of massive star formation in the Galaxy and more accurate testing of massive stellar evolutionary scenarios.

Topics

• impedance spectroscopy