Investigating anomalous microwave emission near G107.2+5.20 in Ku-band with the Green Bank Telescope
arXiv:2607.14084
The authors use Green Bank Telescope Ku‑band observations to map the region around G107.2+5.20, constraining the low‑frequency side of the anomalous microwave emission spectrum and finding that a spinning‑dust model best explains the data, with two distinct 13 GHz excess sources linked to dust and PAH features.
Abstract
Anomalous microwave emission (AME) is 30 GHz-peaking continuum emission thought to arise from spinning dust grains. Observations suggest that the local environment shapes the AME spectral energy distribution (SED), so building a spatially resolved sample of AME regions is a key step towards understanding its emission mechanism. Using the Green Bank Telescope Ku-band receiver, we obtained a ~1 arcmin resolution map of radius 1.25 deg centered on G107.2+5.20. Our first objective was to constrain the low-frequency side of the AME SED with 13 GHz data. Using matched-resolution aperture photometry, we measure the SED from 408 MHz-3 THz and 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 Jy and a peak frequency of GHz. Our second objective was to spatially locate excess 13 GHz emission consistent with spinning dust. We compare our Ku-band map to multi-wavelength gas and dust tracers at ~4 arcmin resolution. We observe two sources of 13 GHz excess at 3 significance consistent with spinning dust emission, though potential contributions from optically thick free-free emission remain ambiguous. ``Region A'' (G106.95+5.19) is spatially coincident with peak dust radiance. ``Region B'' (G107.08+4.90) is spatially coincident with peak PAH abundance. If regions A and B are indeed sources of spinning dust emission, they are a resolved example of how AME-dust correlation varies with environment.
17 pages, 11 figures, submitted to MNRAS on 6/26/26