Rapid and correlated variability of blazar S5 0716+71 from radio- to - - PowerPoint PPT Presentation

Rapid and correlated variability of blazar S5 0716+71 from radio- to sub-mm bands

Lars Fuhrmann

MPIfR, Bonn

&

T.P. Krichbaum, A. Witzel, S. Britzen, I. Agudo, S. Bernhart, V. Impellizerri, A. Kraus, J. Klare, B. W. Sohn, E. Angelakis,

• U. Bach, K. Gab'anyi, E. Koerding, A. Pagels, J. A. Zensus, MPIfR Bonn, Germany
• S. J. Wagner, L. Ostorero, LSW Heidelberg, Germany
• H. Ungerechts, M. Grewing, IRAM
• M. Tornikoski, MRO, Finland
• A. J. Apponi, B. Vila-Vilar'o, L. M. Ziurys, Univ. of Arizona, USA

8th EVN Symposium, September 2006, Torun

Content

Overview Results I Data analysis Results II Conclusions

• L. Fuhrmann, 8th EVN Symposium, September 2006, Torun

Overview

intrinsic radio IDV: inverse Compton (IC) limit might actually be violated, then

• utbursts of IC scattered radiation at X-/γ-ray bands (e.g. Slysh 1992, Bloom &

Marscher 1996) S5 0716+71: z > 0.3 allows only to derive lower limits to lin. size, TB, δ VLBI: kinematic study revealed atypically high apparent speeds of 4.5 --16c and (Bach et al. 2005)

Bach et al. 2005

Overview

coordinated & global multi-frequency campaign - core centered around a 500 ksec Integral pointing during Nov. 10 - 17, 2003 (Ostorero et al. 2006) Aim: search for multi-frequency signatures of IC flashes search for rapid & correlated (intra- to inter-day) variability in the cm- to sub- mm bands and signatures of an IC catastrophe

• simult. constrains on variability TB and δ in comparison with high energy

emission radio telescopes:

.

Radio telescope & Institute Location λobs [mm] WSRT (14x25 m), ASTRON Westerbork, NL 210, 180 Effelsberg (100 m), MPIfR Effelsberg, D 60, 28, 9 Pico Veleta (30 m), IRAM Granada, E 3.5, 1.3 Mets¨ ahovi (14 m), MRO Mets¨ ahovi, Finland 8 Kitt Peak (12 m), ARO Kitt Peak, AZ, USA 3 SMTO/HHT (10 m), ARO

• Mt. Graham, AZ, USA

0.87 JCMT (15 m), JAC Mauna Kea, HI, USA 0.85, 0.45

S5 0716+71 - results I

light curves in the cm regime

2.8 cm 6 cm

S5 0716+71 - results I

light curves in the mm regime

3 mm 9 mm

Agudo et al. 2006

S5 0716+71 - data analysis

Summary: “unusual” monotonic increase in total flux density with variability amplitudes systematically increasing towards higher frequencies combined analysis of all data sets:

time series analysis (SF, ACF, p2p) reveals var. TB ‘s and Doppler factors cross-correlation analysis (CCF) spectral evolution study long-term variability and broad band characteristics

SF & ACF & p2p analysis: tvar > ~ 4 days

TB (type I,cm) > to TB (type I,mm) > to thus, IC limit always violated !

S5 0716+71 - results II

Doppler factors: using the IC limit of (Kellermann & Pauliny-Toth 1969) using the equipartition value of (Readhead 1994)

S5 0716+71 - results II

CCF analysis: variability pattern strongly correlated with systematic trend of increasing time lag towards larger frequency separation flux density increase first at higher frequencies m more pronounced towards higher ν ‘canonical’ behavior: synchrotron cooling & adiab. expansion (e.g. van der Laan 1966, Marscher & Gear 1985) intrinsic !

S5 0716+71 - results II

m vs. ν: comparison with weak scintillation thin screen slab model for weak quenched scattering (Beckert et al. 2002) strong discrepancy between model calculations and observations no strong ISS contribution !

S5 0716+71 results

spectral analysis: Doppler factors from synchrotron & equipartition magnetic field: > 12 -- 23 to

Conclusions

INTEGRAL: no IC catastrophe - only upper limits for soft γ-ray emission IC Doppler factors “unusual” variability behavior in November 2003 intrinsic variations internally consistent lower limits for δ (and ) no IC catastrophe by INTEGRAL & no scintillation violation only apparent & intrinsic Doppler boosting can naturally explain the non-detection at higher energies

S5 0716+71 - results I

towards higher frequencies...

Agudo et al. 2006

1.3 mm