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Extra-galactic Sources: AGN, Blazars, and Dark Matter - Mini-Workshop Summary

This text provides an overview of active galactic nuclei, radio galaxies, blazars, and their properties. It also discusses the correlation between radio and gamma-ray emissions, the diffuse gamma-ray emission from misaligned AGN, and the potential for gamma-ray signals from Dark Matter annihilation. The workshop took place in Pisa, Italy in May 2014.

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Extra-galactic Sources: AGN, Blazars, and Dark Matter - Mini-Workshop Summary

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  1. Gamma da sorgenti extra-galattiche e da DM Fiorenza Donato Università di Torino & INFN Mini-Workshop sulla Fisica Astroparticellare al TEV e oltre Pisa, 8 maggio 2014

  2. Extra-gal sources: Active Galactic Nuclei 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

  3. BL Lacsdata BL Lacs can be classified according to their synchrotron peak frequency νS (low, intermediate, high synchrotron peak): LSP: νS < 1014 Hz ISP: 1014 Hz < νS < 1015 Hz HSP: νS > 1015 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

  4. BL Lacs population study: Luminosity distribution

  5. BL Lacs population study: Redshift distribution

  6. BL Lacs population study: source-count distribution

  7. Observed Spectral Energy Distribution (SED) Power law, PL Log-normal power law (LP) Power-law with exponential cut-off (PLEC) PLEC SED model provides better fits. Huge uncertainties in the cut-off

  8. SED: data and interpretation for LSP Intrinsic (EBL corrected) spectra

  9. SED: data and interpretation for HSP

  10. LISP and HSP SED modelling SED fitted with PLEC

  11. Diffuse γ-ray emission from unresolved BL Lacs • Softening at > 100 GeV due to EBL absorption: data are nicely reproduced! • Treating LSP and HSP separately gives non-negligible differences

  12. Diffuse γ-ray emission fromMisaligned Active Galactic Nuclei (MAGN) • 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, BlLacs 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)

  13. Fermi-LAT MAGNs: main radio and gamma properties MAGN: AGN with jet not aligned along the line-of-sight (l.o.s.) Abundant radio data: total (including lobes) and central region (core) Fermi-LAT observed 15 MAGN between 0.1-100 GeV(Fermi-LAT ApJ 720, 2010) Radio data taken at 5 GHz and near in time to Fermi-LAT measurements * not firmly FRI / FRII RG

  14. 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.

  15. Testing Lγ-Lr correlation: upper limits from undetected FRI&FRII We derive upper limits for FRI and FRII having strong radio core fluxes GREAT!!! they do not violate the correlation  It looks physical

  16. 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 **radio luminosity function from Willott+ 2002 (rescaled from total to core by Lara+ 2004)

  17. Diffuse γ-ray emission from unresolved misaligned AGN Di Mauro,Calore,FD, Ajello, Latronico 2013 Best fit MAGN diffuse flux: 20-30% Fermi-LAT IGRB, |b|>10o Estimated uncertainty band: factor 10

  18. EGB: sum of astrophysical contributions The sum of all the contributions to fits Fermi-LAT (preliminary) EGB data

  19. What about Dark Matter annihilating into gamma-rays?

  20. γ-ray potential DM targets in the sky • Galactic center (GC) •  may be an over-dense region, spectral features could emerge •  high background • Galactic halo: •  low background at high galactic latitudes •  less concentrated DM environment • Galactic sub-structures: •  Could show spatial features (anisotropies) •  small objects, unknown position, number, … • Dwarf spheroidal MW satellites: • DM dominated •  Small number, some are distance-suppressed • Extra-galactic substructures: •  High DM density •  High theoretical uncertainties / faint fluxes

  21. γ-rays from WIMP Dark Matter (DM) • Particle Physics term: acts as a normalization χχ χχ1-loop, Z Radiative correrctions Inverse Compton Integralalong the line-of-sight of DM densitydistribution(r) Derived from numericalsimulations of cosmological structures • Cosmological term

  22. LAT Collaboration linesearch studies (arxiv: 1305.5597) • Analysis with improved calibration constants, in 5 spatial regions • No globally significant lines found (<2σ.) • In a region of 3ox3oaround the GC finds positive excess around 133 GeV, with global significance ~1.6σ. • Excess ~2σ found also for Limb photons (produced by cosmic ray interactions in the upper atmosphere), searched for in a very narrow range of zenith angles. Not compatible with DM interpretation • No excess in the inverse GC region • Unexpected dependence of 133 GeV line on incidence (w.r.t. the detector) angles, both for GC and Limb photons • Set limits to <σv>γγ which do not disfavor the WIMP DM hypothesis in general

  23. γ-ray spectral line: perspectives (http://fermi.gsfc.nasa.gov/ssc/proposals/alt_obs/obs_modes.html) Fermi-LAT default observation is all sky coverage (each 3 hours) since launch (5 yrs). Fermi has solicited white papers for alternate observation strategies for specific science drivers The Recommended Alternative:coverage of the Galactic center region • Implementation from December 2013 • Doubled the rate of accumulation w.r.t present data toward the GC • The modified observing strategy should run for one year. • After one year is up, the Fermi Project Scientist will organize a review to decide whether to maintain the modified observing strategy or return to survey mode. Good perspectives also with Hess-II, Cerenkov Telescope Array (CTA), GAMMA-400 (Bergstrom et al. 2012)

  24. Bounds on WIMP annihilation cross section Bringmann, Calore, FD, Di Mauro, 1303.3284 • Standard halo assumptions I(ψ) • Prompt and IC photons • BR=1 at fixe annih. channel • Bkgd= MAGN + ΣBMS • ΣBMS = MSPs (Calore+2012)+ • BL Lac (Abdo+2010) + • FSRQs (Ajello+2012) + • SF galaxies (Ackermann+2012) • DM + bkgd must not exceed • any data point (at 2σ) Effect of MAGN contribution

  25. Diffuse γ-ray emission from unresolved sources: benchmarks Bringmann, Calore, FD, Di Mauro, 1303.3284

  26. 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)

  27. 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 mDM=1 (10) TeV the constraints on <σv> increase by a factor 10 (50)!

  28. Anisotropies in γ-rays Peculiar DM over-dense regions may imprint spatial signatures in high resolution data Predicted angular power spectrum: galactic and extragalactic Fermi-LAT: detected angular power >3σ in 1-10 GeV range at high l Fornasa et al. 2012 Fermi-Lat Coll. 1202.2856

  29. Anisotropies in γ-rays:the role of the galactic DM radial profile Calore, De Romeri, Di Mauro, Donato, Herpich, Macciò, Maccione MNRAS 2014 Main halo, MW like Typical resolved sub-halo (108.6 – 109.6 M)

  30. Anisotropies in γ-rays:the role of the galactic DM radial profile mDM=200 GeV Eγ=4 GeV <σv>= 310-26 cm3/s • Main halo dominates the low multipole intensity spectrum • Einasto profile gives more anisotropy power at high multipoles • (or small radii; e.g. l=1000 ~ r=30 pc) • If halo is cored  lower intensity but higher probability for DM sub-haloes • to emerge (N.B. no background included; no low latitude mask).

  31. Effect of smaller, unresolved sub-haloes

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