Magnetic Field Strengths in the Hot Spots and Lobes of Three Powerful Fanaroff-Riley Type II Radio Sources
By M. Hardcastle, M. Birkinshaw, R. Cameron, D. Harris, L. Looney, D. Worrall. 2002
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We have made deep Chandra observations of three powerful Fanaroff-Riley type II (FR II) radio sources: two quasars (3C 263 and 3C 351) and one radio galaxy (3C 330). X-ray emission from hot spots and lobes, as well as from the active nucleus, is detected in each source. We model the hot spots' synchrotron spectra using VLA, BIMA, and Hubble Space Telescope data. In 3C 263 and 3C 330, the hot spots' X-ray emission is at a level consistent with being synchrotron self-Compton (SSC) emission, with a hot spot magnetic field close to the equipartition value. In the two hot spots of 3C 351, however, an SSC origin for the X-rays would require the magnetic field strength to be an order of magnitude below the equipartition value in our models; in addition, there are offsets between the radio, optical, and X-ray emission from the secondary hot spot that are hard to explain in a simple SSC model. We discuss the emission mechanisms that may be responsible for these observations. On our preferred model, the X-ray emission from the radio lobes of the three sources is due to inverse Compton scattering of the microwave background radiation. If this is the case, the magnetic field strengths in the lobes are typically about a factor of 2 below the equipartition values, assuming uniform lobe electron and magnetic field distributions. We detect extended X-ray emission, which we attribute to a cluster/group environment, around 3C 263 and 3C 330. This detection allows us to show that the lobes are close to pressure balance with their surroundings, as long as no nonradiating particles contribute to the internal pressure of the lobes.
Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics
View Paper: https://www.semanticscholar.org/paper/da5a195b4218cb55ba281e159e00a844908ab0e7
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Citations in the corpus
- Revised equipartition and minimum energy formula for magnetic field strength estimates from radio synchrotron observations (2005, background): “…galaxies (Brunetti et al. 1997), 100–600µG in hot spots (Carilli et al. 1991; Harris et al. 2000; Wilson et al. 2000; Wilson et al. 2001; Brunetti et al. 2001a; Hardcastle 2001; Hardcastle et al. 2001; 2002), and 0.5–1µG in the diffuse gas of galaxy clusters and relics (Feretti & Giovannini 1996).”
- An X-Ray Study of Magnetic Field Strengths and Particle Content in the Lobes of FR II Radio Sources (2005, methodology): “The results of our survey of FRII radio lobes support the conclusions of our earlier papers on smaller samples of sources (Hardcastle et al. 2002; Croston et al. 2004): the presence of an energetically dominant population of protons is unlikely, because it requires that the magnetic field energy…”
- Radio galaxies and feedback from AGN jets (2020, background): “Constraints derived from luminosity functions of blazars and their presumed parent population of radio galaxies (Urry et al., 1991; Hardcastle et al., 2002) imply bulk beaming speeds of Γ ∼ 3–5.”
- The Origins of X-Ray Emission from the Hot Spots of FR II Radio Sources (2004, methodology): “…predictions of an SSC model with a magnetic field close to the value expected for equipartition of energy between the magnetic field and the radiating electrons, and so their X-ray emission is attributed to the SSC process (e.g. Harris, Carilli & Perley 1994; Hardcastle et al. 2002, hereafter H02).”
- X-Ray Emission from the Hot Interstellar Medium and Southwest Radio Lobe of the Nearby Radio Galaxy Centaurus A (2003, background): “The jet/ lobe morphology of Cen A is clearly different than the ‘‘ tailed twin-jet ’’ morphology (Leahy 1993) commonly associated with objects like 3C 31 (Hardcastle et al. 2002b; Laing & Bridle 2002a, 2002b) and 3C 449 (Feretti et al. 1999).”
- A Survey of Extended Radio Jets with Chandra and the Hubble Space Telescope (2004, background): “In addition, Chandra is now showing that the terminal lobes and hot spots in powerful Fanaroff-Riley II (FR II) jets emit at X-ray, although the origin of the X-ray flux from these structures is still a matter of debate (e.g., Hardcastle et al. 2002a).”
- The X-ray nuclei of intermediate-redshift radio sources (2006, methodology): “A18 3C 351 The parameters of the best-fitting model are similar to thosef und in the analysis of the same data in Hardcastle et al. (2002), but the photon index of the soft power law is even steeper than found in that paper.”
- X-Ray Emission Properties of Large-Scale Jets, Hot Spots, and Lobes in Active Galactic Nuclei (2004, background): “…but the X-ray emissions from the hotspots and radio lobes are also reported in a 1e-mail:kataoka@hp.phys.titech.ac.jp 2e-mail:stawarz@oa.uj.edu.pl number of FR II radio galaxies and quasars (e.g., Wilson, Young & Shopbell 2000; 2001; Hardcastle et al. 2002b; 2004, Tashiro et al. 1998; Isobe 2002).”