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

TL;DR

This study maps the Galactic Center at 2 mm, models dust emission using Herschel data, and isolates specific features like star-forming regions and nonthermal filaments by subtracting the dust model from observations.

Contribution

It introduces a dust emission model based on Herschel data that accurately predicts 2 mm emission, enabling clearer analysis of Galactic Center features.

Findings

Single-temperature dust model fits Herschel data well

Dust emissivity index found to be approximately 2.25

Model subtraction reveals detailed structures in 2 mm emission

Abstract

The Central Molecular Zone (CMZ), covering the inner ~1$^\circ$ of the Galactic plane has been mapped at 2 mm using the 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 $\mu$m emission for most lines of sight, if the long-wavelength dust emissivity scales as $\lambda^{-\beta}$ with $\beta \approx 2.25$. 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.