A Flare in the Jet of Pictor A

The Astrophysical Journal Letters (Impact Factor: 5.34). 04/2010; 714(2):L213. DOI: 10.1088/2041-8205/714/2/L213
Source: arXiv


A Chandra X-ray imaging observation of the jet in Pictor A showed a feature
that appears to be a flare that faded between 2000 and 2002. The feature was
not detected in a follow-up observation in 2009. The jet itself is over 150 kpc
long and a kpc wide, so finding year-long variability is surprising. Assuming a
synchrotron origin of the observed high-energy photons and a minimum energy
condition for the outflow, the synchrotron loss time of the X-ray emitting
electrons is of order 1200 yr, which is much longer than the observed
variability timescale. This leads to the possibility that the variable X-ray
emission arises from a very small sub-volume of the jet, characterized by
magnetic field that is substantially larger than the average over the jet.

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