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M odeling blazar emission

Dan Silano Faculty Mentor : Dr Wiita. M odeling blazar emission. What Is A Blazar?. AGN with relativistic jet pointed along our line of sight Radio loud Exhibits a high degree of polarization Highly variable over a wide range of frequencies

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M odeling blazar emission

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  1. Dan Silano Faculty Mentor : Dr Wiita Modeling blazar emission

  2. What Is A Blazar? • AGN with relativistic jet pointed along our line of sight • Radio loud • Exhibits a high degree of polarization • Highly variable over a wide range of frequencies • Spectrum dominated by synchrotron emission from the jet M87 From Hubble (not technically a blazar)

  3. FSRQ: • Strong emission lines • Synchrotron peak in IR • High redshifts (0.1<z<2.3) • High power (~10^46-48 erg/s) • Subset of Fanaroff-Riley Type 2 (FRII) – has a smooth jet that is collimated *Benoît Lott CEN Bordeaux-Gradignan

  4. BLLac: • Very few emission lines • Synchrotron peak in IR (LBL) or UV/Xray (HBL) • Low redshift (0<z<0.9) • Low power (~10^45-46 erg/s) • Subset of Fanaroff-Riley Type 1 (FRI) – has a distorted jet that isn’t collimated *Benoît Lott CEN Bordeaux-Gradignan

  5. Superluminal Knots *Marscher, 2009

  6. Newtonian Fluid Sim:

  7. Synchrotron Power:

  8. Shock Effects: • Power law spectrum for electron distribution gets boosted up to higher values of gamma while maintaining a slope of -2 • Magnetic field strength is amplified by 5x • Magnetic field strength and gamma values decay exponentially over time

  9. Compton Effects:

  10. Relativistic Effects: • Convert from rest (Jet) frame to lab (detector/earth) frame using the velocity addition formula above (useful for doppler shifts) • Photon tracing algorithm included to avoid unnecessary time-dilation and length-contraction effects

  11. Parameter List (truncated): • static const double J_BETA = -0.995;//B value for the jet • static const double J_ANGLE = 0.0;//angle of jet relative to us in degrees • static const double IC_PROB = 0.05;//probability of Inverse Compton occuring • static const double B_0 = 4.78 * pow(10.0,4.0);//according to shock paper (B value preshock) • static const double J_NULL_POS = 100000.0;//starting position (x-axis) for the jet • static const double SHOCK_POS = 600.0;//position of the shock to the left of the jet starting location (here jet is 600 long) • static const double BLOB_BETA = 0.90; • static const double BLOB_BETA_SD=0.02; • static constint TIME_STEPS = 1600; //total # of time steps • static constint NUM_ZONES = 500;//total number of zones to use • static const double LOW_SYNCH_SLOPE = 5.0/2.0;//slope of low end of synchotron spectrum • static constint GAMMA_BINS = 10;//# of bins to distribute gamma into • static const double GAMMA_MAX = 5.5;//max values for gammas in the jet initially (4.5 seems to be good with 500 bins) • static const double GAMMA_SHOCK = 5.5;//gamma boosting in teh shock • static const double SC_CUTOFF = pow(10.0,13.0);//cutoff for self compton absorption • static const double gammaDecay=1.13;//gammaBoost/gammaDecay for each iteration -> larger value decreases faster

  12. I Am Bad At Flash:

  13. Blazar SED Comparison 1 (FSRQ): • B_0 = 4.78 * pow(10.0,2.0) • GAMMA_MAX = 3.5 • GAMMA_SHOCK = 4.0 • IC_PROB = 0.05 • SC_CUTOFF = pow(10.0,9.0) *Fossati et al, 1998

  14. Blazar SED Comparison 2 (BLLac): • B_0 = 4.78 * pow(10.0,4.0) • GAMMA_MAX = 5.5 • GAMMA_SHOCK = 5.5 • IC_PROB = 0.05 • SC_CUTOFF = pow(10.0,13.0) *Fossati et al, 1998

  15. Output:

  16. Flux / PSD (FSRQ): SI = -1.74

  17. Flux / PSD (BLLac): SI = -0.88

  18. Future Work / Improvements: • Model turbulence using a turbulent spectrum (Kolmogorov) • Run high-resolution computations using a cluster / more CPU time • Optimize synchrotron function • Incorporate relativistic beaming effects on the flux received from individual blobs (computationally intensive) • Compute SC/IC effects to higher order

  19. Sources / Questions: • MARSCHER, A. P. The Compact Structure of Blazars at High Frequencies. Approaching Micro-Arcsecond Resolution with VSOP-2: Astrophysics and Technologies ASP Conference Series, Vol. 402, proceedings of the conference held 3-7 December, 2007, at ISAS/JAXA, Sagamihara, Kanagawa, Japan. Edited by Yoshiaki Hagiwara, Ed Fomalont, Masato Tsuboi, and Yasuhiro Murata., p.194 • Benoît Lott, New insight into Gamma-ray Blazars from the Fermi-LAT, CEN Bordeaux-Gradignan, 2009 • Fossati, G.; Maraschi, L.; Celotti, A.; Comastri, A.; Ghisellini, G. A unifying view of the spectral energy distributions of blazars, 1998MNRAS.299..433F • http://www.cita.utoronto.ca/~everett/agnOverview/agnOverview.html

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