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An explanation to the diffuse gamma-ray emission Fiorenza Donato @ Physics Dept., UN. Torino In collaboration with: M. Ajello, T. Bringmann, F. Calore, A. Cuoco, M. Di Mauro, G. Lamanna L. Latronico, D. Sanchez, P.D. Serpico, J. Siegal-Gaskins “Astroparticle Physics” - Amsterdam, June 26, 2014
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The Fermi-LAT isotropic diffuse emission The origin of the IGRB Undetected sources: AGN (blazars: BL Lacs, FSRQ; mis-aligned AGN) star forming galaxies, (galactic) milli-second pulsars (MSP), […] Diffuse processes: UHECRs interacting with EBL, dark matter annihilation, intergalactic shocks, […] L. Baldini, this conference
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Active Galactic Nuclei 3 Radio quiet AGN: Quasars, Seyfert, Liners Radio loud AGN: Blazars: BL Lacs (no emission lines, closer, less luminous) FSRQ (stronger emission lines, farther, more luminous) Quasars (SSRQ, FSRQ) Radio Galaxies (FRI, FRII) (decreasing view angle) Fermi-LAT data on |b|>10: 1042 sources, 873 associated out of which 357 are BL Lacs and 318 FSRQs Urry & Padovani 1995
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1. Diffuse γ-ray emission from unresolved BL Lacs M. Di Mauro, FD, G. Lamanna, D. Sanchez, P.D. Serpico ApJ 2014 Spectral energy distribution (SED) derived from Fermi-LAT data AND TeV catalogs Luminosity function derived from Fermi-LAT data EBL absorption included (> 100 GeV) Blazars studied according to radio and X-ray classification: Low (High) synchrotron peaked LSP: ν S < 10 14 Hz ISP: 10 14 Hz < ν S < 10 15 Hz HSP: ν S > 10 15 Hz We work with: 80 HSP, 34 ISP, 34 LSP (68 LISP)
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Observed Spectral Energy Distribution (SED) 5 Power-law with exp cut-off provides better fits (huge uncertainties in the cut-off) LSP BL Lac SED HSP BL Lac SED
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Diffuse γ-ray emission from unresolved BL Lacs Di Mauro, FD, Lamanna, Sanchez, Serpico ApJ2014 Softening at > 100 GeV due to EBL absorption: data are nicely reproduced! Treating LSP and HSP separately gives non negligible differences
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2. Diffuse γ-ray emission from Misaligned Active Galactic Nuclei (MAGN) M. Di Mauro, F. Calore, FD, M. Ajello, L. Latronico ApJ 2014 MAGN: AGN with jet not aligned along the line-of-sight (l.o.s.) Doppler boosting negligible Radio galaxies (RG) and steep-spectrum radio quasars (SSRQs) RG have been classified by Fanaroff&Riley (1974) FRI edge-darkened, less powerful, Bl Lacs parent FRII edge-brightened, more powerful, FSRQs parent Abundant RADIO data: total (including lobes) and central compact region (core) Fermi-LAT observed 15 MAGN between 0.1-100 GeV (Fermi-LAT ApJ 720, 2010)
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γ-ray vs radio luminosity function for MAGN Correlation between luminosity of radio core at 5 GHz and γ-ray luminosity > 0.1 GeV The strength of the correlation has been confirmed by the Spearman test and the modified Kendall τ rank correlation test: chance correlation excluded at 95% C.L.
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Constraints from logN-logS The cumulative source number above a given flux: Our assumptions (core radio – γ-ray correlation, link between core and total radio emission, …) are consistent with the Fermi-LAT MAGN number count Consistency also for k=1 (equal number of radio and γ-ray emitters) Trend at lowest fluxes intensity of diffuse flux
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Diffuse γ-ray emission from unresolved misaligned AGN Best fit MAGN diffuse flux: 20-30% Fermi-LAT IGRB, |b|>10 o Estimated uncertainty band: factor 10 Di Mauro,Calore,FD, Ajello, Latronico ApJ2014
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EGB: sum of astrophysical contributions Di Mauro et al. 2014 The sum of all the contributions to fits Fermi-LAT (preliminary) EGB data
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3. Diffuse γ-ray emission from galactic milli-second pulsars (MSPs) Calore, Di Mauro, FD 1406.2706 Galactic MSPs contribution to the IGRB is negligible at all energies
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Anisotropy power spectra from astrophysical sources We study angular power for classes of AGN: -BL Lacs: LISP and HSP (Low, Intermediate and High Synchrotron Peak) -Misaligned AGN (MAGN) -Flat Spectrum Radio Quasar (FSRQ) Cuoco, Di Mauro, FD, Siegal-Gaskins, in preparation PRELIMINARY
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AGN angular power and Fermi-LAT data HSP BL Lacs contribute the most to the anisotropy; high energy spectrum MAGN are very numerous by faint, little amount of AP Fermi-LAT data explained by AGN PRELIMINARY Cuoco, Di Mauro, FD, Siegal-Gaskins, in preparation
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The anisotropy – integrated flux consistency MAGN contribute the most to the IGRB, being very numerous whilst faint HSP BL Lacs get relevant to the highest energies, but sub-dominant Our emission models for AGN are compatible with Fermi-LAT data on anisotropy AND diffuse emission PRELIMINARY Cuoco, Di Mauro, FD, Siegal-Gaskins, in preparation
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Q: Which room is left to Dark Matter annihilation into gamma-rays in the halo of the Milky Way?
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Bounds on WIMP annihilation cross section Standard halo assumptions I( ψ ) Prompt and IC photons BR=1 at fixe annih. channel Bkgd= MAGN + Σ BMS Σ BMS = MSPs (Calore+2012) + BL Lac (Abdo+2010) + FSRQs (Ajello+2012) + SF galaxies (Ackermann+2012) DM + bkgd must not exceed any data point (at 2 σ ) Effect of MAGN contribution Bringmann, Calore, FD, Di Mauro, PRD 2013
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Constraints to DM from diffuse γ-ray emission High latitude data: |b|>10: Bringmann, Calore, Di Mauro, FD 2013 -Negligible the choice for ρ (r) -crucial the backgrounds from extra-galactic unresolved sources Halo 5<|b|<15,|l|<80: Fermi-LAT Coll. 1204.6474 -Models for the diffuse galactic emission improve the limits - Important the choice for ρ (r)
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Conclusions The IGRB is studied for |b|>10 o : faint, diffuse, isotropic flux We present new estimations of the diffuse emission from unresolved BL Lacs, MAGN, MSPs: Fermi-LAT data for the IGRB are very well explained by astrophysical sources Anisotropies for the astrophysical sources compatible with Fermi-LAT data Dark matter: anisotropies depend on the behavior of the density profile extrapolated at low radii We show how much the MAGN background reduces the room left to Dark Matter annihilation
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Testing L γ -L r correlation: upper limits from undetected FRI&FRII GREAT!!! they do not violate the correlation It looks physical We derive upper limits for FRI and FRII having strong radio core fluxes
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Effect of Inverse Compton contribution from e + e - DM annihilation The inclusion of the IC scattering (on CMB, infrared radiation, stellar light) is non-negligible for Wimp Dark Matter masses >~ 100 GeV. At m DM =1 (10) TeV the constraints on increase by a factor 10 (50)!
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Fermi-LAT MAGNs: main radio and gamma properties Some of Fermi-LAT sources are variable Radio CORE data taken at 5 GHz, and contemporary to Fermi-LAT data Up to z~0.7 4 FRII and 8 FRI
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BL Lacs data BL Lacs can be classified according to their synchrotron peak frequency ν S (low, intermediate, high synchrotron peak): LSP: ν S < 10 14 Hz ISP: 10 14 Hz < ν S < 10 15 Hz HSP: ν S > 10 15 Hz We work with: 80 HSP 34 ISP 34 LSP (68 LISP) M. Di Mauro, FD, G. Lamanna, D. Sanchez, P.D. Serpico, ApJ 2014
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Effect of unresolved (smaller) sub-haloes Black lines: Aquarius Aq-A-1 simulated sub-haloes, Einasto profile (Springer+2008) More massive and cored haloes give a flattening at high l (red line) The smaller haloes give more power and a Poisson-like trend Calore, De Romeri, Di Mauro, FD, Herpich, Macciò, Maccione MNRAS 2014
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Simulated all-sky maps E=4 GeV m DM =200 GeV =3×10 26 cm 3 /s Emission from Einasto profile is more clustered. Calore, De Romeri, Di Mauro, FD, Herpich, Macciò, Maccione MNRAS 2014 Einasto Moore-Stadel MS profile shows more extended cores
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Spatial information: Anisotropies in γ-rays Fornasa et al. 2012 Peculiar DM over-dense regions may imprint spatial signatures in high resolution data Fermi-Lat Coll. 1202.2856 Fermi-LAT: detected angular power >3σ in 1-10 GeV range at high l Predicted angular power spectrum: galactic and extragalactic
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