Planck Intermediate Results. IX. Detection of the Galactic haze with Planck

Using precise full-sky observations from Planck, and applying several methods of component separation, we identify and characterize the emission from the Galactic "haze" at microwave wavelengths. The haze is a distinct component of diffuse Galactic emission, roughly centered on the Galactic centre, and extends to |b| ~35 deg in Galactic latitude and |l| ~15 deg in longitude. By combining the Planck data with observations from the WMAP we are able to determine the spectrum of this emission to high accuracy, unhindered by the large systematic biases present in previous analyses. The derived spectrum is consistent with power-law emission with a spectral index of -2.55 +/- 0.05, thus excluding free-free emission as the source and instead favouring hard-spectrum synchrotron radiation from an electron population with a spectrum (number density per energy) dN/dE ~ E^-2.1. At Galactic latitudes |b|<30 deg, the microwave haze morphology is consistent with that of the Fermi gamma-ray "haze" or "bubbles," indicating that we have a multi-wavelength view of a distinct component of our Galaxy. Given both the very hard spectrum and the extended nature of the emission, it is highly unlikely that the haze electrons result from supernova shocks in the Galactic disk. Instead, a new mechanism for cosmic-ray acceleration in the centre of our Galaxy is implied.Comment: 15 pages, 9 figures, submitted to Astronomy and Astrophysic

Planck intermediate results: IX. Detection of the galactic haze with planck

Using precise full-sky observations from Planck, and applying several methods of component separation, we identify and characterise the emission from the Galactic >haze> at microwave wavelengths. The haze is a distinct component of diffuse Galactic emission, roughly centered on the Galactic centre, and extends to | b | ∼ 35-50 in Galactic latitude and | l | ∼ 15-20 in longitude. By combining the Planck data with observations from the Wilkinson Microwave Anisotropy Probe, we were able to determine the spectrum of this emission to high accuracy, unhindered by the strong systematic biases present in previous analyses. The derived spectrum is consistent with power-law emission with a spectral index of-2.56 ± 0.05, thus excluding free-free emission as the source and instead favouring hard-spectrum synchrotron radiation from an electron population with a spectrum (number density per energy) dN/dE ∞ E-2.1. At Galactic latitudes | b | haze> or >bubbles>, while at b ∼-50 we have identified an edge in the microwave haze that is spatially coincident with the edge in the gamma-ray bubbles. Taken together, this indicates that we have a multi-wavelength view of a distinct component of our Galaxy. Given both the very hard spectrum and the extended nature of the emission, it is highly unlikely that the haze electrons result from supernova shocks in the Galactic disk. Instead, a new astrophysical mechanism for cosmic-ray acceleration in the inner Galaxy is implied. © 2013 ESO.The Planck Collaboration acknowledges the support of: ESA; CNES and CNRS/INSU-IN2P3-INP (France); ASI, CNR, and INAF (Italy); NASA and DoE (USA); STFC and UKSA (UK); CSIC, MICINN and JA (Spain); Tekes, AoF and CSC (Finland); DLR and MPG (Germany); CSA (Canada); DTU Space (Denmark); SER/SSO (Switzerland); RCN (Norway); SFI (Ireland); FCT/MCTES (Portugal); and DEISA (EU).Peer Reviewe

Planck intermediate results IX : Detection of the Galactic haze with Planck

Peer reviewe

Planck intermediate results IX. Detection of the Galactic haze with Planck

Using precise full-sky observations from Planck, and applying several methods of component separation, we identify and characterise the emission from the Galactic "haze" at microwave wavelengths. The haze is a distinct component of diffuse Galactic emission, roughly centered on the Galactic centre, and extends to | b | ~ 35-50° in Galactic latitude and | l | ~ 15-20° in longitude. By combining the Planck data with observations from the Wilkinson Microwave Anisotropy Probe, we were able to determine the spectrum of this emission to high accuracy, unhindered by the strong systematic biases present in previous analyses. The derived spectrum is consistent with power-law emission with a spectral index of -2.56 ± 0.05, thus excluding free-free emission as the source and instead favouring hard-spectrum synchrotron radiation from an electron population with a spectrum (number density per energy) dN/dE ∝ E-2.1. At Galactic latitudes | b | < 30°, the microwave haze morphology is consistent with that of the Fermi gamma-ray "haze" or "bubbles", while at b ~ -50° we have identified an edge in the microwave haze that is spatially coincident with the edge in the gamma-ray bubbles. Taken together, this indicates that we have a multi-wavelength view of a distinct component of our Galaxy. Given both the very hard spectrum and the extended nature of the emission, it is highly unlikely that the haze electrons result from supernova shocks in the Galactic disk. Instead, a new astrophysical mechanism for cosmic-ray acceleration in the inner Galaxy is implied. © 2013 ESO

Planck intermediate results IX. Detection of the Galactic haze with Planck

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intermediate results

Using precise full-sky observations from Planck, and applying several methods of component separation, we identify and characterise the emission from the Galactic “haze” at microwave wavelengths. The haze is a distinct component of diffuse Galactic emission, roughly centered on the Galactic centre, and extends to | b |  ~ 35−50° in Galactic latitude and | l |  ~ 15−20° in longitude. By combining the Planck data with observations from the Wilkinson Microwave Anisotropy Probe, we were able to determine the spectrum of this emission to high accuracy, unhindered by the strong systematic biases present in previous analyses. The derived spectrum is consistent with power-law emission with a spectral index of −2.56 ± 0.05, thus excluding free-free emission as the source and instead favouring hard-spectrum synchrotron radiation from an electron population with a spectrum (number density per energy) dN/dE ∝ E-2.1. At Galactic latitudes | b |  < 30°, the microwave haze morphology is consistent with that of the Fermi gamma-ray “haze” or “bubbles”, while at b ~  −50° we have identified an edge in the microwave haze that is spatially coincident with the edge in the gamma-ray bubbles. Taken together, this indicates that we have a multi-wavelength view of a distinct component of our Galaxy. Given both the very hard spectrum and the extended nature of the emission, it is highly unlikely that the haze electrons result from supernova shocks in the Galactic disk. Instead, a new astrophysical mechanism for cosmic-ray acceleration in the inner Galaxy is implied

Planck intermediate results IX. Detection of the Galactic haze with Planck

Using precise full-sky observations from Planck, and applying several methods of component separation, we identify and characterise the emission fromthe Galactic “haze” at microwave wavelengths. The haze is a distinct component of diffuse Galactic emission, roughly centered on the Galactic centre, and extends to |b| ∼ 35−50◦ in Galactic latitude and |l| ∼ 15−20◦ in longitude. By combining the Planck data with observations from the Wilkinson Microwave Anisotropy Probe, we were able to determine the spectrum of this emission to high accuracy, unhindered by the strong systematic biases present in previous analyses. The derived spectrum is consistent with power-law emission with a spectral index of −2.56 ± 0.05, thus excluding free-free emission as the source and instead favouring hard-spectrum synchrotron radiation from an electron population with a spectrum (number density per energy) dN/dE ∝ E−2.1. At Galactic latitudes |b| < 30◦, the microwave haze morphology is consistent with that of the Fermi gamma-ray “haze” or “bubbles”, while at b ∼ −50◦ we have identified an edge in the microwave haze that is spatially coincident with the edge in the gamma-ray bubbles. Taken together, this indicates that we have a multi-wavelength view of a distinct component of our Galaxy. Given both the very hard spectrum and the extended nature of the emission, it is highly unlikely that the haze electrons result from supernova shocks in the Galactic disk. Instead, a new astrophysical mechanism for cosmic-ray acceleration in the inner Galaxy is implied.European Space AgencyCentre National D'etudes SpatialesCNRS/INSU-IN2P3-INP (France)Agenzia Spaziale Italiana (ASI)Italian National Research CouncilIstituto Nazionale Astrofisica (INAF)National Aeronautics & Space Administration (NASA)United States Department of Energy (DOE)Science & Technology Facilities Council (STFC)UKSA (UK)Consejo Superior de Investigaciones Cientificas (CSIC)Spanish GovernmentJA (Spain)Finnish Funding Agency for Technology & Innovation (TEKES)AoF (Finland)CSC (Finland)Helmholtz Association German Aerospace Centre (DLR)Max Planck SocietyCSA (Canada)DTU Space (Denmark)SER/SSO (Switzerland)RCN (Norway)Science Foundation IrelandPortuguese Foundation for Science and TechnologyEuropean Union (EU)National Aeronautics & Space Administration (NASA)Harvey L. Karp Discovery AwardScience & Technology Facilities Council (STFC) ST/G003874/1 ST/J00152X/1 ST/J001562/1 ST/J004812/1 ST/I005765/1 ST/J001538/1 ST/K000985/1 ST/K003674/1 ST/L001314/

Planck intermediate results: IX. Detection of the galactic haze with planck

Using precise full-sky observations from Planck, and applying several methods of component separation, we identify and characterise the emission from the Galactic "haze" at microwave wavelengths. The haze is a distinct component of diffuse Galactic emission, roughly centered on the Galactic centre, and extends to | b | ∼ 35-50 in Galactic latitude and | l | ∼ 15-20 in longitude. By combining the Planck data with observations from the Wilkinson Microwave Anisotropy Probe, we were able to determine the spectrum of this emission to high accuracy, unhindered by the strong systematic biases present in previous analyses. The derived spectrum is consistent with power-law emission with a spectral index of-2.56 ± 0.05, thus excluding free-free emission as the source and instead favouring hard-spectrum synchrotron radiation from an electron population with a spectrum (number density per energy) dN/dE ∞ E-2.1. At Galactic latitudes | b | &lt;30, the microwave haze morphology is consistent with that of the Fermi gamma-ray "haze" or "bubbles", while at b ∼-50 we have identified an edge in the microwave haze that is spatially coincident with the edge in the gamma-ray bubbles. Taken together, this indicates that we have a multi-wavelength view of a distinct component of our Galaxy. Given both the very hard spectrum and the extended nature of the emission, it is highly unlikely that the haze electrons result from supernova shocks in the Galactic disk. Instead, a new astrophysical mechanism for cosmic-ray acceleration in the inner Galaxy is implied. © 2013 ESO