TY - JOUR
T1 - First Detection of Spectral Variations of Anomalous Microwave Emission with QUIJOTE and C-BASS
AU - Cepeda-Arroita, Roke
AU - Harper, Stuart
AU - Dickinson, Clive
AU - Rubiño-Martín, J. A.
AU - Génova-Santos, R. T.
AU - Taylor, Angela C.
AU - Pearson, T. J.
AU - Ashdown, M.
AU - Barr, Adam
AU - Barreiro, R B
AU - Casaponsa, B.
AU - Casas, F. J.
AU - Chiang, H. Cynthia
AU - Fernandez-Cobos, R
AU - Grumitt, R. D. P.
AU - Guidi, F.
AU - Heilgendorff, Heiko M.
AU - Herranz, D.
AU - Jew, Luke R. P.
AU - Jonas, J L
AU - Jones, Michael E
AU - Lasenby, A.
AU - Leech, J
AU - Leahy, John
AU - Martínez-González, E.
AU - Peel, M. W.
AU - Piccirillo, Lucio
AU - Poidevin, F.
AU - Readhead, A. C. S.
AU - {Rebolo}, R
AU - Ruiz-Granados, B.
AU - Sievers, J.
AU - Vansyngel, F.
AU - {Vielva}, P
AU - Watson, Bob
N1 - 18 pages, 7 figures
PY - 2020/1/20
Y1 - 2020/1/20
N2 - Anomalous Microwave Emission (AME) is a significant component of Galactic diffuse emission in the frequency range $10$-$60\,$GHz and a new window into the properties of sub-nanometre-sized grains in the interstellar medium. We investigate the morphology of AME in the $\approx10^{\circ}$ diameter $\lambda$ Orionis ring by combining intensity data from the QUIJOTE experiment at $11$, $13$, $17$ and $19\,$GHz and the C-Band All Sky Survey (C-BASS) at $4.76\,$GHz, together with 19 ancillary datasets between $1.42$ and $3000\,$GHz. Maps of physical parameters at $1^{\circ}$ resolution are produced through Markov Chain Monte Carlo (MCMC) fits of spectral energy distributions (SEDs), approximating the AME component with a log-normal distribution. AME is detected in excess of $20\,\sigma$ at degree-scales around the entirety of the ring along photodissociation regions (PDRs), with three primary bright regions containing dark clouds. A radial decrease is observed in the AME peak frequency from $\approx35\,$GHz near the free-free region to $\approx21\,$GHz in the outer regions of the ring, which is the first detection of AME spectral variations across a single region. A strong correlation between AME peak frequency, emission measure and dust temperature is an indication for the dependence of the AME peak frequency on the local radiation field. The AME amplitude normalised by the optical depth is also strongly correlated with the radiation field, giving an overall picture consistent with spinning dust where the local radiation field plays a key role.
AB - Anomalous Microwave Emission (AME) is a significant component of Galactic diffuse emission in the frequency range $10$-$60\,$GHz and a new window into the properties of sub-nanometre-sized grains in the interstellar medium. We investigate the morphology of AME in the $\approx10^{\circ}$ diameter $\lambda$ Orionis ring by combining intensity data from the QUIJOTE experiment at $11$, $13$, $17$ and $19\,$GHz and the C-Band All Sky Survey (C-BASS) at $4.76\,$GHz, together with 19 ancillary datasets between $1.42$ and $3000\,$GHz. Maps of physical parameters at $1^{\circ}$ resolution are produced through Markov Chain Monte Carlo (MCMC) fits of spectral energy distributions (SEDs), approximating the AME component with a log-normal distribution. AME is detected in excess of $20\,\sigma$ at degree-scales around the entirety of the ring along photodissociation regions (PDRs), with three primary bright regions containing dark clouds. A radial decrease is observed in the AME peak frequency from $\approx35\,$GHz near the free-free region to $\approx21\,$GHz in the outer regions of the ring, which is the first detection of AME spectral variations across a single region. A strong correlation between AME peak frequency, emission measure and dust temperature is an indication for the dependence of the AME peak frequency on the local radiation field. The AME amplitude normalised by the optical depth is also strongly correlated with the radiation field, giving an overall picture consistent with spinning dust where the local radiation field plays a key role.
KW - astro-ph.GA
KW - astro-ph.CO
M3 - Article
SN - 1365-2966
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
ER -