Galactic synchrotron distribution derived from 152 HII region absorption features in the full GLEAM survey

Abstract

We derive the synchrotron distribution in the Milky Way disk from HII region absorption observations over -40° < l < 40° at six frequencies of 76.2, 83.8, 91.5, 99.2, 106.9, and 114.6 MHz with the GaLactic and Extragalactic All-sky Murchison widefield array survey (GLEAM). We develop a new method of emissivity calculation by taking advantage of the Haslam et al., (1981) map and known spectral indices, which enable us to simultaneously derive the emissivity and the optical depth of HII regions at each frequency. We show our derived synchrotron emissivities based on 152 absorption features of HII regions using both the method previously adopted in the literature and our improved method. We derive the synchrotron emissivity from HII regions to the Galactic edge along the line of sight and, for the first time, derive the emissivity from HII regions to the Sun. These results provide direct information on the distribution of the Galactic magnetic field and cosmic-ray electrons for future modelling.

arXiv commentAccepted for publication in MNRAS, 20 pages, 9 figures, 2 tables

References in corpus (35)

• Astropy: A Community Python Package for Astronomy
• The NumPy array: a structure for efficient numerical computation
• LOFAR: The LOw-Frequency ARray
• The Murchison Widefield Array: the Square Kilometre Array Precursor at low radio frequencies
• WSClean: an implementation of a fast, generic wide-field imager for radio astronomy
• A New Model of the Galactic Magnetic Field
• GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey I: A low-frequency extragalactic catalogue
• A model of diffuse Galactic Radio Emission from 10 MHz to 100 GHz
• The WISE Catalog of Galactic HII Regions
• Radio observational constraints on Galactic 3D-emission models
• Pulsar rotation measures and the large-scale structure of Galactic magnetic field
• Science with the Murchison Widefield Array
• GLEAM: The GaLactic and Extragalactic All-sky MWA survey
• The observed spiral structure of the Milky Way
• Global cosmic-ray related luminosity and energy budget of the Milky Way
• Compact continuum source-finding for next generation radio surveys
• Towards a free-free template for CMB foregrounds
• Rotation Measures of Extragalactic Sources Behind the Southern Galactic Plane: New Insights into the Large-Scale Magnetic Field of the Inner Milky Way
• An Improved Model of Diffuse Galactic Radio Emission from 10 MHz to 5 THz
• Modeling the Magnetic Field in the Galactic Disk using New Rotation Measure Observations from the Very Large Array
• Source finding in the era of the SKA (precursors): Aegean 2.0
• The origin of the Local Bubble
• Energy Spectrum of Cosmic-ray Electron and Positron from 10 GeV to 3 TeV Observed with the Calorimetric Electron Telescope on the International Space Station
• All-sky Galactic radiation at 45 MHz and spectral index between 45 and 408 MHz
• The Galactic halo magnetic field revisited
• The nature of the low-frequency emission of M51: First observations of a nearby galaxy with LOFAR
• Finding Distant Galactic HII Regions
• The Radio Sky at Meter Wavelengths: m-Mode Analysis Imaging with the Owens Valley Long Wavelength Array
• A Green Bank Telescope Survey of Large Galactic HII Regions
• Low Frequency Observations of the Moon with the Murchison Widefield Array
• 74 MHz Discrete HII Absorption Regions Towards The Inner Galaxy
• High-Mass Star Formation in the Outer Scutum-Centaurus Arm
• Kinematic distance study of the planetary nebulae-supernova remnant-HII region complex at G35.6-0.5
• A Large Scale, Low Frequency Murchison Widefield Array Survey of Galactic HII regions between 260< l <\340
• Galactic synchrotron emissivity measurements between 250° < l < 355° from the GLEAM survey with the MWA

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• The Global Magneto-Ionic Medium Survey (GMIMS): The brightest polarized region in the Southern sky at 75cm and its implications for Radio Loop II
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