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Gamma-ray (Fermi-LAT) properties of microwave selected AGNs

Gamma-ray (Fermi-LAT) properties of microwave selected AGNs. E. Cavazzuti , D. Gasparrini, P. Giommi, C. Pittori, S. Colafrancesco and On behalf of the Fermi-LAT collaboration The Extreme Sky 2009: sampling the Universe above 10 KeV Otranto, 13 October 2009. Blazars.

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Gamma-ray (Fermi-LAT) properties of microwave selected AGNs

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  1. Gamma-ray (Fermi-LAT) properties of microwave selected AGNs E. Cavazzuti, D. Gasparrini, P. Giommi, C. Pittori, S. Colafrancesco and On behalf of the Fermi-LAT collaboration The Extreme Sky 2009: sampling the Universe above 10 KeV Otranto, 13 October 2009

  2. Blazars • less than 5% of the whole AGN class • beamed (jet at  20-30°) • broad band non thermal continuum, L~1049 erg s-1 • compact morphology (core flux >> extended flux) • flat spectrum (radio spectral index r  0.5) • rapid variability (large L/ t) • high and variable optical polarization • in the gamma rays, they are the most abundant component within the high galactic latitude population of sources. Unification Model (Urry & Padovani 1995): Same Engine, Different Points of View

  3. Inverse Compton SynchrotonRadiation __ Low Peaked Blazar --- High Peaked Blazar -rays TeV Radio wave Visible X-Rays Blazar Spectral Energy Distributions Broad band emission

  4. Emission models: Homogeneous Synchrotron Self Compton, External Compton, Multiple SSC components? Different emitting regions? Acceleration mechanisms Variability Duty cycle Open Questions We investigate these problematics using a multi-wavelength approach through WMAP (-wave) and Fermi (-ray) observations.

  5. Build a complete sample of blazars selected in the microwave band, starting from the WMAP bright source catalogues Study the properties of this microwave selected sample of jet-dominated AGN looking for: synchrotron peak distribution gamma-ray spectral index possible relations between -wave fluxes and X-ray, -ray: duty cycle, , … Strategy

  6. Cosmic Microwave Background Radiation Primordial photons redshifted to microwave frequency due to the Universe expansion We see these photons as cosmic background in microwave band Tiny inhomogeneities in the early universe left their imprint on the CMB in the form of smallanisotropies in its temperature These anisotropies contain information about basic cosmological parameters (e.g. total energy density and curvature of the universe) but between us and CMB there are some foreground sources with microwave emission

  7. WMAP (Wilkinson Microwave Anisotropy Probe) Measurement the temperature differences in the Cosmic Microwave Background (CMB) radiation at five frequencies (23, 33, 41, 61,94 GHz)

  8. sample peaked around typical blazar values The ox - ro diagram: WMAP bright sources (Massaro et al. 2009, A&A, 495, 691) Radio loud Radio quite • 242 FSRQs • 40 BL Lacs • 33 Radio galaxies • 14 Steep Spectrum QSOs • 3 starburst galaxies • 3 planetary nebule • 19 candidate blazar • 27 unidentified • 5 other types TOT 390 (Giommi et al. 2009, astro-ph 0908.0652v1) The vast majority of bright WMAP foreground sources are blazars

  9. 1Jy2227-088=WMAP024 1Jy0805-077=WMAP133 1Jy1548+056=WMAP007 3C395=WMAP034 1Jy1406-07=WMAP203 -wave to X-ray correlation: WMAP - Swift • establish the X-ray properties of a statistically representative sample of -wave selected blazars • verify or exclude the existence of a population of X-ray quiet blazars • compare the X-ray properties of these sources with those of blazars selected in different energy bands • complete the X-ray measurements of a -wave flux-limited sample of blazars, useful for multi- statistical studies IC emission evidence no X quiet population compatible with GHz selected LBL tight WMAP x distribution Fx good estimator for -wave emission (Giommiet al 2007,A&A,468,571) simultaneous data are shown with same symbol

  10. Fermi-LAT Bright AGN source list • 132/205 with |b| > 10 (7 pulsars, 14 unid) • 111/125 are bright, flat spectrum radio sources • 98/111 have optical classifications, 89/111 have redshifts • CRATES (all-sky radio catalog), CGRaBS (all-sky optical spectra), BZCAT • 34% BL Lac fraction (vs 19% for EGRET) (Abdo et al. 2009, ApJ, 700, 597)

  11. Inverse Compton SynchrotonRadiation Preliminary __ Low Peaked Blazar --- High Peaked Blazar -rays TeV Radio wave Visible X-Rays Gamma-ray properties of WMAP balzars The distribution of spectral index confirms the selection of Low Peaked Blazars in the microwave band

  12.   and Duty Cycle (Giommi et al. 2006A&A,445, 843G, Pittori et al. Ap&SS. 309, 89P 2007, Cavazzuti et al. AIPC 921, 246C 2007) Define a -wave to -rayindex: Limiting value: ()100%CGB=0.994 This is the value of an hypotetical source that would produce 100% of the CGB if representative of the class. Any source with < 0.994 shoud have a duty cycle lower than 100% in order not to overproduce the extragalactic diffuse -ray background. Duty cycle > 100% => source always visible (also in low state) where:

  13. -wave to -ray correlation: WMAP - Fermi (mean) UNKN. Preliminary (mean) (100%CGB) (100%CGB) • In 3 months we have seen mostly flaring blazars like EGRET • For the two blazar classes no strong differences in 

  14. Radio to -rays observed correlation • In recent paper (Kovalev et al. 2009) a correlation between high frequency radio (15 GHz) and gamma-ray fluxes is showed. • This set of radio observations are quasi simultaneous to Fermi gamma-ray fluxes (Abdo et al 2009, BSL). • The gamma-ray high variability of blazars blurs the correlation with the microwave band. Kovalev et al.(2009)

  15. Fraction of WMAP sources detected by Fermi Preliminary

  16. Fermi is detecting a significant number (although a small fraction) of powerful microwave emitters. The -wave to X-ray correlation is tight. The -wave to -ray correlation is blurred by large gamma-ray variability of blazars, specially with non-simultaneous data. PLANCK data along with Fermi ones, being both operated in survey mode, will give us unprecedented set of real simultaneous data. Conclusions

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