Investigating anomalous microwave emission near G107.2+5.20 in Ku band with the Green Bank Telescope
- 1Department of Astronomy, The University of Virginia , 530 McCormick Rd, Charlottesville, VA 22904 ,
- 2National Radio Astronomy Observatory , 520 Edgemont Rd, Charlottesville, VA 22903 ,
- 3Jodrell Bank Centre for Astrophysics, Department of Physics & Astronomy, The University of Manchester , Oxford Road, Manchester M13 9PL ,
Abstract
Anomalous microwave emission (AME) is 30-GHz-peaking continuum emission thought to arise from spinning dust grains. Building a spatially resolved sample of regions could offer insight into environmental drivers and the grain populations that produce AME. Using the Green Bank Telescope (GBT) Ku band (12–18 GHz) receiver, we obtained an ∼ 1 arcmin resolution map of radius 1.25∘ centred on G107.2+5.20, encompassing the Sharpless 140 H ii region and Lynds 1204 dark cloud. Our objectives were to (i) measure the rising edge of the AME peak to model the global emission mechanism and (ii) spatially locate excess 13 GHz emission consistent with spinning dust. Using our GBT map and ancillary data, we perform matched-resolution aperture photometry to measure the spectral energy distribution from 408 MHz to 3 THz. We fit two emission models: one including spinning dust, the other optically thick free–free emission. We find that the spinning dust model is superior, with an amplitude of 14.1± 1.1 Jy and a peak frequency of 27± 2 GHz. We compare our Ku-band map to multiwavelength gas and dust tracers at ∼ 4 arcmin resolution. We observe two sources of 13 GHz excess at 3σ significance consistent with spinning dust emission, though potential contributions from optically thick free–free emission remain ambiguous. ‘Region A’ (G106.95+5.19) and ‘Region B’ (G107.08+4.90) are spatially coincident with peak dust radiance and peak polycyclic aromatic hydrocarbon abundance, respectively. If these are, indeed, sources of spinning dust emission, they are a resolved example of how AME–dust correlation varies with environment.
Versions
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BibTeX
@article{shroyer2026investigating,
title = {{Investigating anomalous microwave emission near G107.2+5.20 in Ku band with the Green Bank Telescope}},
author = {Jordan E Shroyer and Bradley R Johnson and Dillon J Bass and Anna Dignan and Stuart E Harper and Brian S Mason and Andrey Moore and Eric J Murphy},
journal = {Monthly Notices of the Royal Astronomical Society},
year = {2026},
month = oct,
doi = {10.1093/mnras/stag1922},
url = {https://academic.oup.com/mnras/article/doi/10.1093/mnras/stag1922/8898893},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Investigating anomalous microwave emission near G107.2+5.20 in Ku band with the Green Bank Telescope
AU - Jordan E Shroyer
AU - Bradley R Johnson
AU - Dillon J Bass
AU - Anna Dignan
AU - Stuart E Harper
AU - Brian S Mason
AU - Andrey Moore
AU - Eric J Murphy
PY - 2026
DA - 2026/10/09
JO - Monthly Notices of the Royal Astronomical Society
DO - 10.1093/mnras/stag1922
UR - https://academic.oup.com/mnras/article/doi/10.1093/mnras/stag1922/8898893
AB - Anomalous microwave emission (AME) is 30-GHz-peaking continuum emission thought to arise from spinning dust grains. Building a spatially resolved sample of regions could offer insight into environmental drivers and the grain populations that produce AME. Using the Green Bank Telescope (GBT) Ku band (12–18 GHz) receiver, we obtained an ∼ 1 arcmin resolution map of radius 1.25^∘ centred on G107.2+5.20, encompassing the Sharpless 140 H ii region and Lynds 1204 dark cloud. Our objectives were to (i) measure the rising edge of the AME peak to model the global emission mechanism and (ii) spatially locate excess 13 GHz emission consistent with spinning dust. Using our GBT map and ancillary data, we perform matched-resolution aperture photometry to measure the spectral energy distribution from 408 MHz to 3 THz. We fit two emission models: one including spinning dust, the other optically thick free–free emission. We find that the spinning dust model is superior, with an amplitude of 14.1± 1.1 Jy and a peak frequency of 27± 2 GHz. We compare our Ku-band map to multiwavelength gas and dust tracers at ∼ 4 arcmin resolution. We observe two sources of 13 GHz excess at 3σ significance consistent with spinning dust emission, though potential contributions from optically thick free–free emission remain ambiguous. ‘Region A’ (G106.95+5.19) and ‘Region B’ (G107.08+4.90) are spatially coincident with peak dust radiance and peak polycyclic aromatic hydrocarbon abundance, respectively. If these are, indeed, sources of spinning dust emission, they are a resolved example of how AME–dust correlation varies with environment.
SN - 0035-8711
SN - 1365-2966
ER -