Multiwavelenth Observations Of Strong Flares From The Tev Blazar 1ES 1959+650

Reporter:倪嘉阳Arthor:H.Krawczynski, S.B. Hughes

2013.10.08

Introduction

• Detection of strong TeV γ-ray flares from the BL Lac object 1ES 1959+650

• Intensive target of opportunity radio, optical, X-ray, and TeV γ-ray observations

• There was six well-established TeV Blazars at that time(see table 1)

• Long flaring phases can be recognized in three sources

• Mrk 501 flared in 1997 but showed only modest fluxes thereafter

• Flaring phases offer ideal opportunities to study these objects

Data sets and data reduction

• Radio observations

UMRAO at 4.8 and 14.5 GHz between 2002 May and August 9

Additional flux density measurements: VLA of the NRAO

• Optical observations (two optical data sets)

0.4m telescope at Boltwood Observatory, using V, R, and I broadband filters

0.7m telescope at the Abastmani Observatory in Georgia, using an R filter for all observations

• X-ray observations

3-25 keV data from the PCA on board the RXTE satellite

Standard procedure to reduce the data to get the light curves and spectra

• Gamma-ray observations

Whipple 10 m Cerenkov telescope

The HEGRA system of five Cerenkov telescopes

Results of the multiwavelenth campaign

• Analyse of every figure• For analyzing the X-ray flux variability, compute the e-folding times:

• Shortest e-folding times• Analyze photon index variations

)10(ln keVFt

Detailed light curves

• Divide the data into four epochs• Epoch 1(May 16-25;MJD 52410-52419): γ-ray

and X-ray fluxes seem to be correlated• Epoch 2(May 26-June 21;MJD 52420-52446)• the strong ophan γ-ray flare on June 4,shown

in more detail • Epoch 3(July 5-19;MJD 52460-52474)• Epoch 4(July 31-August 14;MJD 52486-52500)

Flux correlations in different energy bands

the correlation between simultaneously measured γ-ray and X-ray fluxes during the full campaign

X-ray hardness-intensity correlation

The correlation between 3-25keV X-ray photon index and the 10 keV flux

Spectral energy distribution and SSC modeling

• X-ray emission: synchrotron self-Compton(SSC) mechanism

• Γ-ray emission: inverse Compton scattering of synchrotron photons

• The radio-to-γ-ray SED of 1ES 1959+650, together with a simple one-zone SSC model

The orphan γ-ray flare in the frame of SSC models

• It is not possible to produce an orphan γ-ray flare by moving the high-energy cutoff of accelerated electrons to higher energies

• Adding a low energy electron population succeeds in producing an orphan γ-ray flare

• Postulating a second, dense electron population within a small emission region

Correlations between emission parameters and black hole mass indicators

conclusion

• Presenting evidence for an “orphan” γ-ray flare without an X-ray counterpart

• There are several ways to explain the orphan flare Multiple-Component SSC Models External Compton Models Magnetic Field Aligned along Jet axis Proton Models• It cannot be explained with conventional one-zone

SSC model