Abstract: Linking the synchrotron and Compton components in Mkn 421 with simultaneous, intensive X-ray/TeV monitoring (PI: R. Edelson)

Coordinated monitoring reveals correlated X-ray/TeV variations in blazars, but large gaps in the TeV light curves make it impossible to track the evolution of flares. We will use CAT, MAGIC, Whipple, PACT, STACEE, CELESTE and other telescopes to measure the first near-continuous blazar TeV light curve: 7.9 days in Feb/Mar 2003 on the bright, strongly-variable blazar Mkn 421. We request simultaneous RXTE monitoring to establish the first unambiguous link between the putative Compton and synchrotron components. This will determine the gamma-ray production mechanism and strongly constrain physical conditions in the jet. We will also undertake the first rigorous searches for phase and amplitude differences between bands and "orphan" X-ray or TeV-only flares that would favor external Compton or hadronic models.