University of Hertfordshire

From the same journal

From the same journal

By the same authors

A flare in the jet of Pictor A

Research output: Contribution to journalArticlepeer-review

  • H.L. Marshall
  • M.J. Hardcastle
  • M. Birkinshaw
  • J.H. Croston
  • D. Evans
  • H. Landt
  • E. Lenc
  • F. Massaro
  • E. Perlman
  • D.A. Schwartz
  • A. Siemiginowska
  • L. Stawarz
  • C.M. Urry
  • D.M. Worrall
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Original languageEnglish
Pages (from-to)L213-L216
JournalAstrophysical Journal Letters
Publication statusPublished - 2010


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 about 1 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 years, 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 a magnetic field that is substantially larger than the average over the jet.


Original article can be found at: Copyright American Astronomical Society. [Full text of this article is not available in the UHRA]

ID: 162882