Systematic effects in the extraction of the 'WMAP haze'
arXiv:1004.3056 · doi:10.1088/1475-7516/2010/10/019
Abstract
The extraction of a 'haze' from the WMAP microwave skymaps is based on subtraction of known foregrounds, viz. free-free (bremsstrahlung), thermal dust and synchrotron, each traced by other skymaps. While the 408 MHz all-sky survey is used for the synchrotron template, the WMAP bands are at tens of GHz where the spatial distribution of the radiating cosmic ray electrons ought to be quite different because of the energy-dependence of their diffusion in the Galaxy. The systematic uncertainty this introduces in the residual skymap is comparable to the claimed haze and can, for certain source distributions, have a very similar spectrum and latitudinal profile and even a somewhat similar morphology. Hence caution must be exercised in interpreting the 'haze' as a physical signature of, e.g., dark matter annihilation in the Galactic centre.
17 pages, 12 figures; improved diffusion model; extended discussion of spectral index maps; clarifying comments, figures and references added; to appear in JCAP
References in corpus (13)
- Observation of an anomalous positron abundance in the cosmic radiation
- Measurement of the Cosmic Ray e+ plus e- spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope
- The Parkes multibeam pulsar survey: VI. Discovery and timing of 142 pulsars and a Galactic population analysis
- The Spectrum of the Isotropic Diffuse Gamma-Ray Emission Derived From First-Year Fermi Large Area Telescope Data
- The origin of the positron excess in cosmic rays
- Extended Anomalous Foreground Emission in the WMAP 3-Year Data
- Evidence Of Dark Matter Annihilations In The WMAP Haze
- Bayesian component separation and CMB estimation for the 5-year WMAP temperature data
- Can the WMAP Haze really be a signature of annihilating neutralino dark matter?
- Systematic Effects in Extracting a "Gamma-Ray Haze" from Spatial Templates
- Measuring interstellar magnetic fields by radio synchrotron emission
- A Galactic Cosmic-Ray Database
- Cosmic-ray electrons, synchrotron and magnetic fields in the Galaxy