1. Anisotropy and Energy Spectrum of the CGB as probes of Dark Matter and Astrophysical Sources June 21-26, 2010, CCAPP, Ohio State University Shin’ichiro Ando (Caltech, Pasadena CA, USA) Enzo Branchini (University of "Roma Tre", Rome, Italy) Alessandro Cuoco (Stockholm U., Sweden) Mattia Fornasa (Instituto de Astrofisica de Andalucia, Spain) Brandon Hensley (Caltech, Pasadena CA, USA) Tim Linden (UC Santa Cruz CA, USA) Vasiliki Pavlidou (Caltech, Pasadena CA, USA) Rebecca Reesman (OSU, Columbus, OH, USA) Jennifer Siegal-Gaskins (CCAPP, OSU, Columbus OH, USA) Gianfranco Bertone (IAP Paris, ITP Zurich) Eiichiro Komatsu (UT, Austin, TX, USA) Lidia Pieri (University of Padova, Italy) Stefano Profumo (UC Santa Cruz CA, USA)

2. What this is about There is dark matter… …so we would like to find an annihilation signature of it… … in the Fermi gamma-ray background… … using spectral and spatial information as tools… … but it is difficult… … and we would like to quantify how difficult it is… … and try to find clever ways around the difficulties

3. A nod to our sponsors:

4. The gamma-ray sky Fermi 1yr, E>300MeV Credit: Fermi LAT collaboration

5. What is making the GeV isotropic diffuse background? ----- Unresolved point sources Guaranteed sources: active galaxies, star-forming galaxies, millisecond pulsars Hypothesized source classes: galaxy clusters, dark matter cusps +

6. The “Isotropic” Gamma-ray Background active galaxies Abdo et al. 2010 millisecond pulsars Linden et al, in preparation Star-forming galaxies Fields, VP & Prodanovic 2010 Complications: multi-component, backgrounds and signal uncertain, EBL absorption uncertain, no spectral handles dark matter Abdo et al. 2010 galaxy clusters Keshet et al 2003

7. How to break the degeneracies? We need more observables! 1. The angular power spectrum Blazars Ando, Komatsu, Narumoto & Totani 2007 Galactic subhalos Siegal-Gaskins 2008 Galactic and EG subhalos Fornasa, Pieri, Bertone & Branchini 2009 Extragalactic DM Cuoco et al 2008 Galaxy Clusters Ando, Komatsu, Narumoto & Totani 2007 Galactic subhalos Ando 2009 Starforming Galaxies Ando &VP 2009 DM around IMBH: Taoso, Ando, Bertone & Profumo 2008

8. How to break the degeneracies? 2. The anisotropy energy spectrum Siegal-Gaskins & VP 2009 Combine w/ intensity energy spectrum… decomposition possible! see Hensley talk! Cuoco et al. 2010 Hensley, Siegal-Gaskins & VP 2010

9. How to break the degeneracies? 3. Other: bring people together to compare + combine methods control uncertainties brainstorm for new ideas University of Zurich, November 2009 http://www2.iap.fr/users/bertone/GinZ/Workshop.html

10. What next? Theoretical predictions of CGB intensity spectra, angular power spectra need to be updated using new data from Fermi [blazars, SF galaxies] How much uncertainty in these models? Sources of false positives: –What spectral signals may look like dark matter? (pulsars? EBL? Other?) –What anisotropy signatures may look like dark matter? –What astrophysical populations / processes may induce modulations in the anisotropy energy spectrum? (e.g. EBL horizon, redshifting of spectral features) In which scenarios is a DM feature detectable ? In which scenarios can individual contributions be deconvolved? How many can we separate? Andy Strong’s Observable : Time-dependence: should go down in a predictable way; Define flux sensitivity which is assumed in each case George Lake’s test : in any given model for background, how many point sources should I already have detected?

11. Fornasa et al. in preparation Since then… Pieri, lavalle, Bertone & Branchini arXiv:0908.0195 Hensley, Siegal-Gaskins & VP Cuoco et al. 2010 2010, arXiv:0912.1854 2010, arXiv:1005.0843 sensitivity of intensity + anisotropy probes Hensley, VP & Siegal-Gaskins in preparation: decomposition into constituents (see Hensley talk) Linden et al. in preparation, Reesman et al. in preparation: millisecond pulsars Ando & VP in preparation: update on SF galaxies Fermi Data analysis! The angular power spectrum of the Fermi gamma-ray Background Siegal-Gaskins Cuoco Linden VP + Komatsu + other members of the LAT collaboration Results by end of July