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Anisotropy and Energy Spectrum of the CGBas 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)

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

A nod to our sponsors:

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The gamma-ray sky

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Fermi 1yr, E>300MeVCredit: Fermi LAT collaboration

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

+

The “Isotropic” Gamma-ray Background

active galaxiesAbdo et al. 2010

millisecond pulsarsLinden et al, in preparation

Star-forming galaxiesFields, VP & Prodanovic 2010

Complications: multi-component, backgrounds and signal uncertain, EBL absorption uncertain, no spectral handles

dark matter

Abdo et al. 2010

galaxy clustersKeshet et al 2003

How to break the degeneracies?We need more observables!1. The angular power spectrum

BlazarsAndo, Komatsu, Narumoto & Totani 2007

Galactic subhalosSiegal-Gaskins 2008

Galactic and EG subhalosFornasa, Pieri, Bertone & Branchini 2009

Extragalactic DMCuoco et al 2008

Galaxy ClustersAndo, Komatsu, Narumoto & Totani 2007

Galactic subhalosAndo 2009

Starforming GalaxiesAndo &VP 2009

DM around IMBH: Taoso, Ando, Bertone & Profumo 2008

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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

How to break the degeneracies?

3. Other: bring people together to compare + combine methods control uncertainties brainstorm for new ideas

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University of Zurich, November 2009http://www2.iap.fr/users/bertone/GinZ/Workshop.html

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?

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Fornasa et al. in preparation

Since then…

Pieri, lavalle, Bertone & Branchini arXiv:0908.0195

Hensley, Siegal-Gaskins & VP Cuoco et al. 20102010, arXiv:0912.1854 2010, arXiv:1005.0843sensitivity 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-GaskinsCuocoLindenVP+Komatsu+other members of theLAT collaboration

Results by end of July