1. Igor V. Moskalenko (Stanford U.) with A.Strong (MPE), S.Digel (SLAC), T.Porter (USCS), O.Reimer (SU) Modeling of the Galactic diffuse continuum γ-ray emission

2. Igor V. Moskalenko 2 July 4, 20066 th INTEGRAL Workshop/Moscow GLAST Large Area Telescope (LAT) EGRET (>100 MeV) Simulated LAT (>1 GeV, 1 yr) This is an animation that steps from 1. EGRET (>100 MeV), to 2. LAT (>100 MeV), to 3. LAT (>1 GeV) Seth Digel

3. Igor V. Moskalenko 3 July 4, 20066 th INTEGRAL Workshop/Moscow Diffuse Galactic Gamma-ray Emission ~80% of total Milky Way luminosity at HE !!! Tracer of CR (p, e − ) interactions in the ISM (π 0,IC,bremss): oStudy of CR species in distant locations (spectra & intensities)  CR acceleration (SNRs, pulsars etc.) and propagation oEmission from local clouds → local CR spectra  CR variations, Solar modulation oMay contain signatures of exotic physics (dark matter etc.)  Cosmology, SUSY, hints for accelerator experiments oBackground for point sources (positions, low latitude sources…) Besides: oForeground in studies of the extragalactic diffuse emission oExtragalactic diffuse emission (blazars ?) may contain signatures of exotic physics (dark matter, BH evaporation etc.) Calculation requires knowledge of CR (p,e) spectra in the entire Galaxy

4. Igor V. Moskalenko 4 July 4, 20066 th INTEGRAL Workshop/Moscow CR Interactions in the Interstellar Medium e + - PHeCNO X,γ gas ISRF e + - π + - P_LiBeB ISM diffusion energy losses energy losses reacceleration reacceleration convection convection etc. etc. π 0 synchrotron IC bremss Chandra GLAST ACE helio-modulation p 42 sigma (2003+2004 data) HESS Preliminary SNR RX J1713-3946 PSF BHeCNO Flux 20 GeV/n CR species:  Only 1 location  modulation e + - π + - PAMELA BESS AMS

5. Igor V. Moskalenko 5 July 4, 20066 th INTEGRAL Workshop/Moscow A Model of CR Propagation in the Galaxy  Gas distribution (Leiden-Argentina-Bonn HI, CfA CO surv.)  Interstellar radiation field (87 stellar classes, gas, dust, including heating and re-emission)  Source distribution (SNR, pulsars)  Nuclear & particle production cross sections (LANL, Webber)  Gamma-ray production: brems, IC, π 0  Energy losses: ionization, Coulomb, brems, IC, synch  Solve transport equations for all CR species (~90!)  Fix propagation parameters

6. Igor V. Moskalenko 6 July 4, 20066 th INTEGRAL Workshop/Moscow Wherever you look, the GeV  -ray excess is there ! 4a-f EGRET data

7. Igor V. Moskalenko 7 July 4, 20066 th INTEGRAL Workshop/Moscow Reacceleration Model vs. Plain Diffusion Plain Diffusion (D xx ~β -3 R 0.6 ) Diffusive Reacceleration B/C ratio Antiproton flux B/C ratio

8. Igor V. Moskalenko 8 July 4, 20066 th INTEGRAL Workshop/Moscow More excesses: Positron Excess ? HEAT (Beatty et al. 2004) GALPROP 1 E, GeV 10 e + /e HEAT 2000 HEAT 1994-95 HEAT combined 1 E, GeV 10 Q: Are all the excesses connected? A: “Yes” and “No” Same progenitor (CR p or DM) for pbars, e + ’s, γ’s… or a local positron source? Systematic errors of different detectors E > 6 GeV

9. Igor V. Moskalenko 9 July 4, 20066 th INTEGRAL Workshop/Moscow GeV excess: Optimized/Reaccleration model Uses all sky and antiprotons & gammas to fix the nucleon and electron spectra  Uses antiprotons to fix the intensity of CR nucleons @ HE  Uses gammas to adjust  the nucleon spectrum at LE  the intensity of the CR electrons (uses also synchrotron index)  Uses EGRET data up to 100 GeV protons electrons x4 x1.8 antiprotons E k, GeV

10. Igor V. Moskalenko 10 July 4, 20066 th INTEGRAL Workshop/Moscow Secondary e ± are seen in γ-rays ! Improves an agreement in MeV range brems IC In the heliosphere: e + /e~0.2 In the Galaxy: e + /e~1 <1 GeV electrons positrons sec.

11. Igor V. Moskalenko 11 July 4, 20066 th INTEGRAL Workshop/Moscow Distribution of CR Sources & Gradient in the CO/H 2 CR distribution from diffuse gammas (Strong & Mattox 1996) SNR distribution (Case & Bhattacharya 1998) sun X CO =N(H 2 )/W CO : Histo –This work, Strong et al.’04 ------Sodroski et al.’95,’97 1.9x10 20 -Strong & Mattox’96 ~Z -1 – Boselli et al.’02 ~Z -2.5 - Israel’97,’00, [O/H]=0.04,0.07 dex/kpc Pulsar distribution Lorimer 2004

12. Igor V. Moskalenko 12 July 4, 20066 th INTEGRAL Workshop/Moscow Seth Digel’05 Gas Rings: HI (Our Neighborhood) Longitude Latitude

13. Igor V. Moskalenko 13 July 4, 20066 th INTEGRAL Workshop/Moscow Interstellar radiation field R= 0 kpc 4 kpc 8 kpc 12 kpc 16 kpc Local ISRF stars IR CMB The ISRF plays an important role: Generation of Galactic diffuse  -ray emission (IC) IC energy losses of electrons and positrons It is very intense in the Galactic center Attenuation of TeV  -ray sources (see Poster 18C !) scattered

14. Igor V. Moskalenko 14 July 4, 20066 th INTEGRAL Workshop/Moscow Anisotropic Inverse Compton Scattering  Electrons in the halo see anisotropic radiation  Observer sees mostly head-on collisions e-e- e-e- head-on: large boost & more collisions γ γ small boost & less collisions γ sun Energy density Z, kpc R=4 kpc Important @ high latitudes !

15. Igor V. Moskalenko 15 July 4, 20066 th INTEGRAL Workshop/Moscow Effect of anisotropic ICS Galactic latitude, degrees Ratio anisoIC/isoIC Intermediate latitudes GC anti-GC pole The anisotropic IC scattering plays important role in modeling the Galactic diffuse emission Affects estimates of isotropic extragalactic background

16. Igor V. Moskalenko 16 July 4, 20066 th INTEGRAL Workshop/Moscow Latitude profile of the outer Galaxy anisotropic IC The aniso IC is maximal (x2) in the outer Galaxy around b=20  -30  Agreement with data impossible without aniso IC Latitude isoIC bremsstrahlung 00 Total EG

17. Igor V. Moskalenko 17 July 4, 20066 th INTEGRAL Workshop/Moscow Diffuse emission from the inner Galaxy The “optimized” model describes the spectrum of the diffuse emission from MeV to TeV energies Predictions down to keV’s (note, INTEGRAL data include positronium continnum) MeV region appears to be transitional between Galactic and EG emission dominance Extragalactic EGRET ASCA HEAO A2 HEAO A4 COMPTEL G+EG EGRET G COMPTEL (Strong’99) EG COMPTEL (Weidenspointner’00) EG EGRET (Strong’04) INTEGRAL (Strong’05) isoIC anisoIC Total Galactic G+EG G+EG COMPTEL Positronium + sources??

18. Igor V. Moskalenko 18 July 4, 20066 th INTEGRAL Workshop/Moscow Conclusions We are building a model of the diffuse emission preparing for the GLAST mission The diffuse emission model becomes more realistic now with more prediction capability outside the MeV- GeV region MeV region is transitional (Galactic vs. extragalactic dominance) On the other hand, GLAST will resolve 1000’s of unresolved sources putting stricter constraints on the diffuse emission model Prepare to see unexpected ! This will have an impact on CR studies, derivation and interpretation of the extragalactic background, and will possibly affect the dark matter studies

19. Igor V. Moskalenko 19 July 4, 20066 th INTEGRAL Workshop/Moscow Diffuse emission from the outer Galaxy anisotropic IC isoIC bremss