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Galactic Foreground cleaning in gamma-rays

Galactic Foreground cleaning in gamma-rays. Anisotropy Workshop, June 23 th 2010. Alessandro Cuoco, Oskar Klein Center, Stockholm University. The Microwave sky. In addition to CMB photons, WMAP data is “contaminated” by a number of galactic foregrounds that must be accurately subtracted

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Galactic Foreground cleaning in gamma-rays

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  1. Galactic Foreground cleaning in gamma-rays Anisotropy Workshop, June 23th 2010 Alessandro Cuoco, Oskar Klein Center, Stockholm University

  2. The Microwave sky • In addition to CMB photons, WMAP data is “contaminated” by a number of galactic foregrounds that must be accurately subtracted • The WMAP frequency range is well suited to minimize the impact of foregrounds • Substantial challenges are involved in identifying and removing foregrounds

  3. Template fitting

  4. Synchrotron: Template: C.G.T. Haslam et al., A&A 100 (1981) 209. Synchrotron + Freefree: Template: D.P. Finkbeiner, ApJS 146 (2003) 407. Free-free + Dust:Template: D.P. Finkbeineret al., ApJ 524 (1999) 867. T & S Dust WMAP + TOTAL CMB CMB: Gold et al., arXiV:1001.4555.

  5. The “WMAP Haze” D. P. Finkbeiner, Astrophys. J. 614 (2004) 186 G. Dobler and D. P. Finkbeiner, arXiv:0712.1038 [astro-ph]. After known foregrounds are subtracted, an excess appears in the residual maps within the inner ~20 around the Galactic Center

  6. WMAP Team foreground analysis and the Haze The fit procedure used for the haze extraction is quite important, and using more degrees of freedom to model the foregrounds as performed by the WMAP team fails in finding the feature. They still find an hardening of the synchrotron emission in the Haze region, though. Map of the synchrotron spectral indexes in a pixel by pixel fit procedure by WMAP Synchrotron spectral indexes averaged along constant longitudes stripes by WMAP WMAP Collaboration (B. Gold et al.) 2008 [arXiv:astro-ph/0803.0715]. D.T. Cumberbatch,, arXiv:0902.0039 [astro-ph].

  7. The Gamma Sky • Galactic Contribution from: • Pion Decay • Inverse Compton • Electron Bremsstrahlung Galprop Foregrounds Model: Moskalenko et al.

  8. Morphology of the gamma-sky components

  9. A Fermi Haze? Dobler, Finkbeiner et al. 2009

  10. Further directions: Multi-template fitting using gas rings?

  11. More directions: Planck dust map(s) as gas templates

  12. Lot of work to do…

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