Green Bank Telescope Multiwavelength Survey of the Galactic Center Region

Abstract

We describe the results of a radio continuum survey of the central 4° × 1° with the 100 m Green Bank Telescope (GBT) at wavelengths of 3.5, 6, 20, and 90 cm. The 3.5 and 6 cm surveys are the most sensitive and highest resolution single-dish surveys made of the central degrees of our Galaxy. We present catalogs of compact and extended sources in the central 4° of our Galaxy, including detailed spectral index studies of all sources. The analysis covers star-forming regions such as Sgr B and Sgr C, where we find evidence of a mixture of thermal and nonthermal emission. The analysis quantifies the relative contribution of thermal and nonthermal processes to the radio continuum flux density toward the Galactic center (GC) region. In the central 4° × 1° of the GC, the thermal and nonthermal flux fractions for all compact and diffuse sources are 28%/72% at 3.5 cm and 19%/81% at 6 cm. The total flux densities from these sources are 783 ± 52 and 1063 ± 93 Jy at 3.5 and 6 cm, respectively, excluding the contribution of Galactic synchrotron emission.