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Researchers used the Green Bank Telescope to map anomalous microwave emission (AME) near galaxy region G107.2+5.20, finding evidence that the signals originate from spinning dust grains rather than other emission sources. They identified two distinct regions showing excess 13 GHz emission at different locations - one coinciding with peak dust radiance and another with peak polycyclic aromatic hydrocarbon (PAH) abundance, demonstrating how AME varies with local environmental conditions.
Why it matters
Understanding the sources of microwave emission in space is crucial for accurately interpreting cosmic microwave background observations and filtering out foreground signals that could interfere with cosmological studies. This work provides spatially resolved evidence for how dust grain properties and local chemistry influence microwave signals, improving our ability to distinguish between different astrophysical emission mechanisms.
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⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
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 $14.1pm1.1$ Jy and a peak frequency of $27pm2$ 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$sigma$ 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.
Source: Investigating anomalous microwave emission near G107.2+5.20 in Ku-band with the Green Bank Telescope