SIMBAD references

2018MNRAS.475.5116W - Mon. Not. R. Astron. Soc., 475, 5116-5132 (2018/April-3)

A spatially resolved radio spectral index study of the dwarf irregular galaxy NGC 1569.

WESTCOTT J., BRINKS E., HINDSON L., BESWICK R. and HEESEN V.

Abstract (from CDS):

We study the resolved radio continuum spectral energy distribution of the dwarf irregular galaxy, NGC 1569, on a beam-by-beam basis to isolate and study its spatially resolved radio emission characteristics. Utilizing high-quality NRAO Karl G. Jansky Very Large Array observations that densely sample the 1-34 GHz frequency range, we adopt a Bayesian fitting procedure, where we use H α emission that has not been corrected for extinction as a prior, to produce maps of how the separated thermal emission, non-thermal emission, and non-thermal spectral index vary across NGC 1569's main disc. We find a higher thermal fraction at 1 GHz than is found in spiral galaxies (26+2–3percent) and find an average non-thermal spectral index α = -0.53 ± 0.02, suggesting that a young population of cosmic ray electrons is responsible for the observed non-thermal emission. By comparing our recovered map of the thermal radio emission with literature H α maps, we estimate the total reddening along the line of sight to NGC 1569 to be E(B - V) = 0.49 ± 0.05, which is in good agreement with other literature measurements. Spatial variations in the reddening indicate that a significant portion of the total reddening is due to internal extinction within NGC 1569.

Abstract Copyright: © The Author(s) 2018. Published by Oxford University Press on behalf of The Royal Astronomical Society.

Journal keyword(s): methods: data analysis - techniques: interferometric - cosmic rays - H ii regions - ISM: magnetic fields - radio continuum: galaxies

Simbad objects: 11

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