1 / 20

Tadayuki Takahashi Institute of Space and Astronautical Science (ISAS)

Spectral and Temporal Variations of Blazars. Tadayuki Takahashi Institute of Space and Astronautical Science (ISAS). Hidetoshi Kubo(Kyoto), Jun Kataoka (Tokyo IT), Chiharu Tanihata (ISAS). 3C46 (1.4 GHz). Cosmic Ray Spectrum. core (AGN) + inner jet. knot. Yes:AGN. lobe. hot spot.

ellis
Download Presentation

Tadayuki Takahashi Institute of Space and Astronautical Science (ISAS)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Spectral and Temporal Variations of Blazars Tadayuki Takahashi Institute of Space and Astronautical Science (ISAS) Hidetoshi Kubo(Kyoto), Jun Kataoka (Tokyo IT), Chiharu Tanihata (ISAS)

  2. 3C46 (1.4 GHz) Cosmic Ray Spectrum core (AGN) + inner jet knot Yes:AGN lobe hot spot Cosmic-ray and Particle Accelerator • Where are accelerators? • What’s the maximum energy? • How powerful? • “Black Holes” are important players? Blazars are ideal objects to study the behavior of particleaccelerators at the bottom of Jets

  3. Gamma-ray Blazars Third EGRET AGN Catalogue • Gamma-rays • Direct evidence of the existence of GeV/TeV particles • the emitting source cannot be • too compact • too close to important sources of X-ray photon (e.g. a hot accretion disk corona close to the black hole) to avoid γγ-> e+e- EGRET sky map of AGNs TeV detection

  4. Mrk 421 1995 ASCA Fossatti et al. 2003 Whipple (TeV) EGRET Takahashi et al. 1999 Takahashi et al. 1996,1999 Macomb et al. 1995 X-Gamma CorrelationsX and γ-rays are cospatial

  5. GBLK ~ 10 Dominated by non-thermal highly variable broad-band radiation observer produced in relativistic jets pointing close to the line of sight • Enhancement • by Relativistic Beaming(Lobs〜Ld4) • = 1/{GBLK (1-b cosq)} High Power Small Emax Low Power High Emax Kataoka 2002 Gamma-ray Blazars • Fit to • Spectral Energy Distribution • (SED) • -> Parameters of Accelerators • based on the assumption of • Synchrotron • Inverse Compton • Sync. Photon (and External) • Peak frequency relations • Lumunosity relations

  6. Solve “Parent” electron distributionfrom the spectra • Self-consistent analysis can constrain • Size • Magnetic Field • Beaming Factor • Electron Distribution(Kinetic Power) 5x105 gmax = 105 X-ray gmin = 1 gmin = 1000 X-ray band is sensitive to γmax and γmin

  7. 2000 2000 cnts/s 1day time (x 10,000 s) Takahashi et al. 1999 ASCA’s Long-look Observation (Still Difficult for XMM/Chandra) Daily Flare Shape : almost symmetric : Light Crossing Effect in the blob (not the effect of cooling/acceleration time constant) Offset Component (pedestal) Temporal Variations (TeV Blazars)at the maximum end of electron distribution

  8. Tanihata et al. 2003 Takahashi et al. 2000 Kataoka et al. 2001 Spectral Variations (TeV Blazars)at the maximum end of electron distribution

  9. Acceleration/Cooling Flare light curve is symmetric. No energy dependence found in rise/decay. tcool (Obs. Frame) B=0.1 Gauss d= 10 0.5 keV … 17,000 s 5 keV … 5,000 s (at X-rays) High if shock velocity (vs) is high or d is high

  10. Time dependent treatment New Component (ex. with higher γmax) • Time dependent modeling is important to study the spectral evolution (but available only very recently) • time scale of • Acceleration and Cooling • Escape (Kirk et al. 1999, Kataoka et al. 2000, Krawczynski et al. 2002) • Predicts characteristic spectral evolution (such as “soft lag/hard lag”) , from the balance between tacc and tcool. Injection B=0.1 gauss R=1016 cm3 … Solve the time evolution of electrons escape Flare Light Curve Kataoka 2000

  11. Mrk421 1 day Mrk501 tvar PKS2155-304 Characteristic Time Scale • Both • Structure Function • PSD • analysis indicate • time variablity <tvar • is greatly • suppressed for t < tvar - • Daily flares are commonly observed • Characteristic time scale : tvar 〜 40ks - 100ks R 〜 ctvard〜1016[cm]

  12. D ~ GBLK2 D0 ～ 1017 [cm] d~ 2D0 t B.H. R ~ GBLK D0 ~ 1016[cm] 1/GBLK G2 G1 shock 0.5 - 1 day variability roughly corresponds to 10 Rg for 109 M (Rees 1978 Ghisellini 1999, Spada et al. 2001 Kataoka et al. 2001) Internal Shocks Variablity Fast shell catches up the slow shell Link to the Characteristic time scale of the ejection from BH. (Kataoka et al. 2001, Iwashimizu et al. 2003)

  13. F large DG smaller DG OFFSET Time No. of flares offset Day-by-day flares Internal Energy Flare time-scale (ksec) log D (cm) Light Curve Simulation -Gｍ= 10, sG = 0.005, D0 = 3×1013[cm] Tanihata et al. 2003 • Blobs mainly collide atD ~ 103-4 D0 = 1017-20 [cm] • Only the flares due to collisions at the smallest distance • will be appeared as “shots (daily flares)” offset component structure function

  14. Observation Simulation EUVE 1keV 6.3keV 15keV Application to Mrk 421 • Rfo=0.7, Tchr =40 ks ⇒ D 0 =1x1013 cm sG =0.015, G=15 (assumed) -> very narrow distribution is required Light Curve (Flare, Energy dependent Amplitudes, SF/PSD are OK. Efficiency <0.01 % Similar Analysis by Guetta et al. 2002 provides Efficiency < several % still small assumption Energy carried out by the form of Jet does not go into electron acceleration/radiation

  15. One more issue to tackle with Absorption effect (TeV γ)by Diffuse Extragalactic Background Radiation Need to correct TeV spectra for the SED fitting, if the emission exceeds several TeV F. Aharonian 2003

  16. shock shock Re-visiting SED Analysis D for Mrk 421 B.H. Takahara et al. (Poster 81) Flare δ=37, B=0.012G Flare in 2000 Another approach to fit FLARE IR absorption corrected for TeV spectra (important) Fit quiescent phase to determine parameters. Use higher G for flare, scale other parameters with G . Collision takes place at longer distance for larger G maximum energy is higher for larger G Quiescence δ=12, B=0.12G Change of the parameters of accelerator ?

  17. Before CGRO/TeV/ASCA Inhomogenious Model (continuous flow) After X-Gamma Correlation Homogenious One Zone Model After Detections of Flare & Spectral Evolution Time-Dependent One Zone Model After Characteristic Time Scale (Daily Flare) Time Dependent (Internal Shocks) Multi Zone? Paradigm Shift

  18. AstroE2 GLAST GLAST 2006 ISAS Future Observations ? Kataoka et al. 1999 GLAST SKY poster by Fukazawa et al.

  19. Conclusion • We have a fairly good understanding of Blazar Spectra (Parameters of Accelerators); ue>uB • X-ray/TeV correlations give strong constraint on the model • Low Efficiency in sub-pc jets (Blazar emission) • Most of the energy carried out from BH is transported to kpc-jets and Lobes (See Poster 32 by Kataoka) • Shift of Paradigm Time Dependent Model is indispensable Internal Shock Model (Multi Zone?) • Need sensible and Detector in hard-X and Gamma

  20. ISAS BGO Narrow FOV Compton Telescope for the NeXT mission in Japan • Incident angle of γ-rays are defined by a well-type active collimator (Extremely Low Background) • Stack Configuration • Low Energy 24 layers of Strip Strip detectors (res. 400μm) and 6 mm thick CdTe Pixel (res. 1mm) • High Energy Resolution of <1 - 3 keV

More Related