Open AccessThe X‐ray jet and halo of PKS 0521−365
Author(s) -
Birkinshaw M.,
Worrall D. M.,
Hardcastle M. J.
Publication year - 2002
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2002.05615.x
Subject(s) - physics , astrophysics , astronomy , rosat , bl lac object , halo , radio galaxy , galactic halo , galaxy , surface brightness , blazar , gamma ray
ChandraACIS observations of PKS 0521−365 find that the X‐ray emission of this BL Lac object consists of emission from an unresolved core, a diffuse halo and a 2‐arcsec jet feature coincident with the inner radio/optical jet. A comparison with a new ATCA 8.6‐GHz map also finds X‐ray emission from the bright hotspot south‐east of the nucleus. The jet spectrum, from radio to X‐ray, is probably synchrotron emission from an electron population with a broken power‐law energy distribution, and resembles the spectra seen from the jets of low‐power (FR I) radio galaxies. The hotspot X‐ray flux is consistent with the expectations of synchrotron self‐Compton emission from a plasma close to equipartition, as seen in studies of high‐power (FR II) radio galaxies. While the angular structure of the halo is similar to that found by an analysis of theROSATHigh Resolution Imager image, its brightness is seen to be lower withChandra , and the halo is best interpreted as thermal emission from an atmosphere of similar luminosity to the haloes around FR I radio galaxies. The X‐ray properties of PKS 0521−365 are consistent with it being a foreshortened, beamed, radio galaxy.