NOEMA High Fidelity Imaging of the Molecular Gas in and around M82

Abstract

We present a 154 pointing IRAM NOEMA mosaic of the CO(1-0) line emission in and around the nearby starburst galaxy M82. The observations, complemented by zero--spacing observations, reach a spatial resolution of $\sim$30 pc ($\sim 1.9^{\prime \prime }$) at 5.0 km s${}^{-1}$ spectral resolution, sufficient to resolve the molecular gas in the central starburst disk, the outflow, as well as the tidal streamers. The resulting moment and peak brightness maps show a striking amount of structure. Using a clump decomposition algorithm, we analyse the physical properties (e.g., radii $R$, line widths $\sigma$, and masses $M$) of $\sim 2000$ molecular clouds. To first order, the clouds' properties are very similar, irrespective of their environment. This also holds for the size-line width relations of the clouds. The distribution of clouds in the ${\sigma }^2/R$ vs. column density $\Sigma$ space suggests that external pressure does not play a significant role in setting their physical parameters in the outflow and the streamers. We find that the clouds in the streamers stay approximately constant in size ($R\sim 50$ pc) and mass ($M\sim 10^5$ M${}_{\odot }$) and do not vary with their projected distance from M82's center. The clouds in the outflow, on the other hand, appear to decrease in size and mass with distance towards the Southern outflow. The reduction in the molecular gas luminosity could be indicative of cloud evaporation of embedded clouds in the hot outflow.

16 pages, 10 figures, 2 tables; accepted for publication in ApJ

References in corpus (17)

• Array Programming with NumPy
• The Resolved Properties of Extragalactic Giant Molecular Clouds
• Cool Outflows in Galaxies and their Implications
• The Launching of Cold Clouds by Galaxy Outflows I: Hydrodynamic Interactions with Radiative Cooling
• Iron line and diffuse hard X-ray emission from the starburst galaxy M82
• Multiphase Gas and the Fractal Nature of Radiative Turbulent Mixing Layers
• Extended Mid-Infrared Aromatic Feature Emission in M 82
• FellWalker - a Clump Identification Algorithm
• Hydrodynamical Coupling of Mass and Momentum in Multiphase Galactic Winds
• Interaction of a cold cloud with a hot wind: the regimes of cloud growth and destruction and the impact of magnetic fields
• A deep X-ray observation of M82 with XMM-Newton
• Warm Molecular Hydrogen in the Galactic Wind of M82
• Temperature and Metallicity Gradients in the Hot Gas Outflows of M82
• A Framework for Multiphase Galactic Wind Launching using TIGRESS
• Assessing the Performance of Molecular Gas Clump Identification Algorithms
• The turbulent gas structure in the centers of NGC253 and the Milky Way
• The Molecular Baryon Cycle of M82

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• JWST Observations of Starbursts: Relations between PAH features and CO clouds in the starburst galaxy M 82
• Sub-kiloparsec empirical relations and excitation conditions of HCN and HCO+ J=3-2 in nearby star-forming galaxies
• Observational Constraints on Cool Gas Clouds in M82's Starburst-Driven Outflow
• CO Emission Delineating the Interface between the Milky Way Nuclear Wind Cavity and the Gaseous Disk
• A sensitive, high-resolution, wide-field IRAM NOEMA CO(1-0) survey of the very nearby spiral galaxy IC 342
• JWST Observations of Starbursts: PAHs Closely Trace the Cool Phase of M82's Galactic Wind
• Origin of the diffuse 4-8 keV emission in M82
• Revisiting the Galactic Winds in M82 II: Development of Multiphase Outflows in Simulations
• A Fast, Hot Wind from a Nuclear Starburst
• JWST Observations of Starbursts: Dust Processing in the M82 Superwind