Spinning nano-carbon grains: Viable origin for anomalous microwave emission

Abstract

Context. Excess microwave emission, commonly known as anomalous microwave emission (AME), is now routinely detected in the Milky Way. Although its link with the rotation of interstellar (carbonaceous) nano-grains seems to be relatively well established at cloud scales, large-scale observations show a lack of correlation between the different tracers of nano-carbons and AME, which has led the community to question the viability of this link. Aims. Using ancillary data and spinning dust models for nano-carbons and nano-silicates, we explore the extent to which the AME that come out of the Galactic Plane might originate with one or another carrier. Methods. In contrast to previous large-scale studies, our method is not built on comparing the correlations of the different dust tracers with each other, but rather on comparing the poor correlations predicted by the models with observed correlations. This is based on estimates that are as realistic as possible of the gas ionisation state and grain charge as a function of the local radiation field and gas density. Results. First, nano-carbon dust can explain all the observations for medium properties, in agreement with the latest findings about the separation of cold and warm neutral medium in the diffuse interstellar medium. The dispersion in the observations can be accounted for with little variations in the dust size distribution, abundance, or electric dipole moment. Second, regardless of the properties and abundance of the nano-silicate dust we considered, spinning nano-silicates are excluded as the sole source of the AME. Third, the best agreement with the observations is obtained when the emission of spinning nano-carbons alone is taken into account. However, a marginal participation of nano-silicates in AME production cannot be excluded as long as their abundance does not exceed $Y_{\mathrm{Si}}\sim 1\%$.

accepted for publication by A&A

References in corpus (18)

• Infrared Emission from Interstellar Dust. IV. The Silicate-Graphite-PAH Model in the Post-Spitzer Era
• HI4PI: A full-sky HI survey based on EBHIS and GASS
• The evolution of amorphous hydrocarbons in the ISM: dust modelling from a new vantage point
• Separation of anomalous and synchrotron emissions using WMAP polarization data
• A refined model for spinning dust radiation
• Dust variations in the diffuse interstellar medium: constraints on Milky Way dust from Planck-HFI observations
• The 21-SPONGE HI Absorption Survey I: Techniques and Initial Results
• Centimeter-wave continuum radiation from the rho Ophiuchi molecular cloud
• Modeling the Anomalous Microwave Emission with Spinning Nanoparticles: No PAHs Required
• Cold and warm atomic gas around the Perseus molecular cloud I: Basic Properties
• Dust processing in photodissociation regions - Mid-IR emission modelling
• Dust properties inside molecular clouds from coreshine modeling and observations
• Extracting the cold neutral medium from HI emission with deep learning: Implications for Galactic foregrounds at high latitude
• Shiva: the dust destruction model
• Probing Interstellar Grain Growth Through Polarimetry in the Taurus Cloud Complex
• Investigation of the Origin of the Anomalous Microwave Emission in Lambda Orionis
• The evolution of hydrocarbon dust grains in the interstellar medium and its influence on the infrared spectra of dust
• Multi-wavelength observations and modelling of a quiescent cloud LDN1512

Cited by in corpus (2)

• The Astrodust+PAH Model: A Unified Description of the Extinction, Emission, and Polarization from Dust in the Diffuse Interstellar Medium
• QUIJOTE scientific results -- X. Spatial variations of Anomalous Microwave Emission along the Galactic plane