Contents List of Figures

6.6 Structure and Emission of Micro–Jets 293
core, however, is usually unpolarized. 2
6.6.2 Emission Properties
As the brightest and nearest quasar (z = 0.158), 3C 273 is an ideal laboratory to
study emission processes for jets in quasars. This source displays significant flux
variations, has a well measured wide band spectral energy distribution and has
a relativistic jet emanating from the central part in a galaxy. This collimated jet
structure extends up to 150 kpc from the core, depending on the unknown inclination
towards the observer. 3C 273 is classified as a blazar – though I find this notion
somewhat misleading – and is also a prominent gamma–ray source.
3C 273 and the hard X–ray emission: Recently, the results of a long–term
monitoring of 3C 273 with RXTE have been published (Kataoka et al. 2002). This
covers the longest observation period in the hard X–rays (about 835 ksec, Fig. 140).
Most of the 3C 273 photon spectra observed between 1996 and 2000 can be fitted
Figure 140: RXTE light curves of 3C 273 in the hard X–rays (Katakoa et al. 2002).
The data are binned in 10 days intervals.
by a power–law spectrum with spectral index αX = 1.6 ± 0.1. This is consistent
with previously published data. Multifrequency spectra provide information for
physical quantities relevant to the jet physics, e.g. the magnetic field, the size of
the emission region, the maximum energy and the density of relativistic electrons.
2 For a movie see http://www.bu.edu/blazars/3C120.html