2 mm GISMO Observations of the Galactic Center. I. Dust Emission*

Abstract

The central molecular zone, covering the inner ∼1° of the Galactic plane has been mapped at 2 mm using the Goddard-IRAM Superconducting 2-Millimeter Observer (GISMO) bolometric camera on the 30 m IRAM telescope. The 21″ resolution maps show abundant emission from cold molecular clouds, from star-forming regions, and from one of the Galactic center nonthermal filaments. In this work we use the Herschel Hi-GAL data to model the dust emission across the Galactic center. We find that a single-temperature fit can describe the 160–500 μ m emission for most lines of sight, if the long-wavelength dust emissivity scales as λ − β with β  ≈ 2.25. This dust model is extrapolated to predict the 2 mm dust emission. Subtraction of the model from the GISMO data provides a clearer look at the 2 mm emission of star-forming regions and the brightest nonthermal filament.