Istituto di Scienza e Tecnologie dell'Informazione     
Salerno E., Bedini L., Planck Collaboration .. Planck intermediate results. XII: Diffuse Galactic components in the Gould Belt system. In: Astronomy & Astrophysics, vol. 557 article n. A53. ESO, 2013.
We perform an analysis of the diffuse low-frequency Galactic components in the southern part of the Gould Belt system (130◦ ≤ l ≤ 230◦ and −50◦ ≤ b ≤ −10◦). Strong ultra-violet flux coming from the Gould Belt super-association is responsible for bright diffuse foregrounds that we observe from our position inside the system and that can help us improve our knowledge of the Galactic emission. Free-free emission and anomalous microwave emission (AME) are the dominant components at low frequencies (ν < 40 GHz), while synchrotron emission is very smooth and faint. We separated diffuse free-free emission and AME from synchrotron emission and thermal dust emission by using Planck data, complemented by ancillary data, using the correlated component analysis (CCA) component-separation method and we compared our results with the results of cross-correlation of foreground templates with the frequency maps. We estimated the electron temperature Te from Hα and free-free emission using two methods (temperature-temperature plot and cross-correlation) and obtained Te ranging from 3100 to 5200 K for an effective fraction of absorbing dust along the line of sight of 30% ( fd = 0.3). We estimated the frequency spectrum of the diffuse AME and recovered a peak frequency (in flux density units) of 25.51.5 GHz. We verified the reliability of this result with realistic simulations that include biases in the spectral model for the AME and in the free-free template. By combining physical models for vibrational and rotational dust emission and adding the constraints from the thermal dust spectrum from Planck and IRAS, we are able to present a good description of the AME frequency spectrum for plausible values of the local density and radiation field.
URL: http://www.aanda.org/articles/aa/abs/2013/09/aa21160-13/aa21160-13.html
DOI: 10.1051/0004-6361/201321160
Subject Component separation
Correlated component analysis
Galaxy: general - radio continuum
ISM-radiation mechanism: general
Anomalous microwave emission

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