WE PROPOSE TO OBSERVE A HIGH-FREQUENCY PEAKED BL LAC (HBL) OBJECT IN OUTBURST SIMULTANEOUSLY WITH XMMNEWTON AND GROUND-BASED TEV CHERENKOV TELESCOPE ARRAYS. THE MAIN GOAL OF THE PROPOSED OBSERVATION IS TO STUDY THE VARIABILITY OF HBLS ON SUB-HOUR TIMESCALES JOINTLY AT X-RAY AND TEV ENERGIES. XMM COVERS A CRITICAL SPECTRAL RANGE FOR STUDYING HBLS BECAUSE THE SYNCHROTRON EMISSION OF SUCH SOURCES PEAKS IN OR NEAR ITS PASSING BAND. THE DATA WILL ALLOW INVESTIGATIONS OF CORRELATED VARIABILITY OF THE X-RAY AND TE V GAMMARAY EMISSION SPECTRAL HYSTERESIS AND EVOLUTION AND HARDNESS-INTENSITY CORRELATION IN A HIGH-FLUX STATE. THE RESULTS MAY SHED SIGNIFICANT LIGHT ON THE PROPERTIES OF EMITTING REGIONS AND MECHANISMS (I.E. LEPTONIC VS HADRONIC) IN THE JETS OF TE V GAMMA-RAY BLAZARS.

The Trustees Of Columbia University In The City Of New York

Investigators