<i>Planck</i>intermediate results. XV. A study of anomalous microwave emission in Galactic clouds
Bibliographic record
Abstract
Anomalous microwave emission (AME) is believed to be due to electric\ndipole radiation from small spinning dust grains. The aim of this paper\nis a statistical study of the basic properties of AME regions and the\nenvironment in which they emit. We used WMAP and Planck maps, combined\nwith ancillary radio and IR data, to construct a sample of 98 candidate\nAME sources, assembling SEDs for each source using aperture photometry\non 1�-smoothed maps from 0.408 GHz up to 3000 GHz. Each spectrum is\nfitted with a simple model of free-free, synchrotron (where necessary),\ncosmic microwave background (CMB), thermal dust, and spinning dust\ncomponents. We find that 42 of the 98 sources have significant\n(>5sigma) excess emission at frequencies between 20 and 60 GHz. An\nanalysis of the potential contribution of optically thick free-free\nemission from ultra-compact H ii regions, using IR colour criteria,\nreduces the significant AME sample to 27 regions. The spectrum of the\nAME is consistent with model spectra of spinning dust. Peak frequencies\nare in the range 20-35 GHz except for the California nebula (NGC 1499),\nwhich appears to have a high spinning dust peak frequency of (50\n� 17) GHz. The AME regions tend to be more spatially extended\nthan regions with little or no AME. The AME intensity is strongly\ncorrelated with the sub-millimetre/IR flux densities and comparable to\nprevious AME detections in the literature. AME emissivity, defined as\nthe ratio of AME to dust optical depth, varies by an order of magnitude\nfor the AME regions. The AME regions tend to be associated with cooler\ndust in the range 14-20 K and an average emissivity index,\nbeta<SUB>d</SUB>, of +1.8, while the non-AME regions are typically\nwarmer, at 20-27 K. In agreement with previous studies, the AME\nemissivity appears to decrease with increasing column density. This\nsupports the idea of AME originating from small grains that are known to\nbe depleted in dense regions, probably due to coagulation onto larger\ngrains. We also find a correlation between the AME emissivity (and to a\nlesser degree the spinning dust peak frequency) and the intensity of the\ninterstellar radiation field, G<SUB>0</SUB>. Modelling of this trend\nsuggests that both radiative and collisional excitation are important\nfor the spinning dust emission. The most significant AME regions tend to\nhave relatively less ionized gas (free-free emission), although this\ncould be a selection effect. The infrared excess, a measure of the\nheating of dust associated with H ii regions, is typically >4 for AME\nsources, indicating that the dust is not primarily heated by hot OB\nstars. The AME regions are associated with known dark nebulae and have\nhigher 12 mum/25 mum ratios. The emerging picture is that the bulk\nof the AME is coming from the polycyclic aromatic hydrocarbons and small\ndust grains from the colder neutral interstellar medium phase.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".