Magnetic field strengths in the hotspots of 3C 33 and 111

Hardcastle, M. J.; Birkinshaw,; Worrall,

doi:10.1046/j.1365-8711.1998.01159.x

Cited by 51 publications

(22 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The brightest newly detected X-ray hotspots in our sample are the southern hotspot and knot of PKS 1733−56 and the S hotspot of PKS 2356−61. To test whether these two hotspots are synchrotron or inverse-Compton (synchrotron self-Compton) in origin we used the measured 1-keV flux density and the radio flux density of the corresponding hotspot to carry out inverse-Compton calculations using the code of Hardcastle et al (1998). As the radio maps we have are all of low resolution, we estimate the hotspot sizes for these two objects from the fact that they appear unresolved or marginally resolved in the Chandra data, and assign all the measured radio flux density from Gaussian fitting to a spherical region of radius 1 arcsec.…”

Section: Hotspotsmentioning

confidence: 99%

See 1 more Smart Citation

An X-ray survey of the 2 Jy sample – II. X-ray emission from extended structures

Mingo

Hardcastle

Ineson

et al. 2017

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

The 2Jy sample is a survey of radio galaxies with flux densities above 2 Jy at 2.7 GHz. As part of our ongoing work on the southern subset of 2Jy sources, in paper I of this series we analysed the X-ray cores of the complete 2Jy sample with redshifts 0.05 < z < 0.7. For this work we focus on the X-ray emission associated with the extended structures (jets, lobes, and environments) of the complete subset of 2Jy sources with 0.05 < z < 0.2, that we have observed with Chandra. We find that hotspots and jet knots are ubiquitous in FRII sources, which also inhabit systematically poorer environments than the FRI sources in our sample. Spectral fits of the hotspots with good X-ray statistics invariably show properties consistent with synchrotron emission, and we show that inverse-Compton mechanisms under-predict the X-ray emission we observe by 1-2 orders of magnitude. Inverse-Compton emission is detected from many of the lobes in our sample, and we find that the lobes of the FRII sources show magnetic fields lower by up to an order of magnitude than expected from equipartition extrapolations. This is consistent with previous results, which show that most FRII sources have electron energy densities higher than minimum energy requirements.cores of the 2Jy sources in the subset of Dicken et al. (2008), using data from Chandra and XMM-Newton, and found our results to be in good agreement with those of Hardcastle et al. (2006Hardcastle et al. ( , 2009 on the 3CRR radio galaxies.In this work we focus on the extended X-ray emission (jets, hotspots, and lobes) and the environments of the 0.05 < z < 0.2 subset of sources that we have observed with Chandra, whose nuclei we studied in paper I. Our knowledge of X-ray jets (see e.g. the review by Worrall 2009) and hotspots (e.g. Hardcastle et al. , 2007bMassaro et al. 2010Massaro et al. , 2015 has certainly improved over the last two decades, as has our understanding of the environment in which radio galaxies live (e.g. Belsole et al. 2007;Croston et al. 2008;Ineson et al. 2013Ineson et al. , 2015, but the samples of radio galaxies with available detailed observations are still relatively small, and more work needs to be done to understand their extended structures and how they co-evolve with the hosts (see also the recent review by Tadhunter 2016). The 2Jy sample is important in that it is not only statistically complete, but uniformly observed, with c 0000 The Authors

show abstract

Section: Hotspotsmentioning

confidence: 99%

“…The blue dashed arrow indicates the enhancement in X-ray emission that might correspond to the jet. Hardcastle et al (1998). SYNCH uses the radio spectrum and a given magnetic field to model the underlying relativistic electron population and its interaction with photons from the cosmic microwave background (CMB) and synchrotron emission.…”

Section: Lobesmentioning

confidence: 99%

An X-ray survey of the 2 Jy sample – II. X-ray emission from extended structures

Mingo

Hardcastle

Ineson

et al. 2017

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…(13) over a fixed range in observed frequency, not in electron energy, although the latter seems more physically reasonable (Myers and Spangler 1985;Brunetti et al 1997;Hardcastle et al 1998) and the differences between these two sets of assumptions can lead to significantly different results (Beck and Krause 2005).…”

Section: Measuring Magnetic Field Strengths On the Kpc Scalementioning

confidence: 96%

Magnetic Fields in Astrophysical Jets: From Launch to Termination

Hardcastle¹,

Gabuzda²

2012

Space Sciences Series of ISSI

View full text Add to dashboard Cite

Long-lived, stable jets are observed in a wide variety of systems, from protostars, through Galactic compact objects to active galactic nuclei (AGN). Magnetic fields play a central role in launching, accelerating, and collimating the jets through various media. The termination of jets in molecular clouds or the interstellar medium deposits enormous amounts of mechanical energy and momentum, and their interactions with the external medium, as well, in many cases, as the radiation processes by which they are observed, are intimately connected with the magnetic fields they carry. This review focuses on the properties and structures of magnetic fields in long-lived jets, from their launch from rotating magnetized young stars, black holes, and their accretion discs, to termination and beyond. We compare the results of theory, numerical simulations, and observations of these diverse systems and address similarities and differences between relativistic and non-relativistic jets in protostellar versus AGN systems. On the observational side, we focus primarily on jets driven by AGN because of the strong observational constraints on their magnetic field properties, and we discuss the links between the physics of these jets on all scales.

show abstract

“…Carilli et al 1991). However, many studies suggest that γ min is somewhere between 100 and 1000 for FRII hotspots (Carilli et al 1991;Hardcastle et al 1998a;Godfrey et al 2009;McKean et al 2016). Moderate filling factors and a proton population that does not dominate the energetics are still consistent with SSC model predictions (Hardcastle et al 2004), so in principle a magnetic field strength of up to B eq ∼ 70 µG may still be possible ( f = 0.1, 6 k is the ratio of total energy in non-radiating particles to that in synchrotron-emitting leptons.…”

Section: Internal Faraday Depolarizationmentioning

confidence: 99%

Faraday rotation at low frequencies: magnetoionic material of the large FRII radio galaxy PKS J0636−2036

O’Sullivan

Lenc

Anderson

et al. 2018

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We present a low-frequency, broadband polarization study of the FRII radio galaxy PKS J0636−2036 (z = 0.0551), using the Murchison Widefield Array (MWA) from 70 to 230 MHz. The northern and southern hotspots (separated by ∼14.5 ′ on the sky) are resolved by the MWA (3 ′ .3 resolution) and both are detected in linear polarization across the full frequency range. A combination of Faraday rotation measure (RM) synthesis and broadband polarization model-fitting are used to constrain the Faraday depolarization properties of the source. For the integrated southern hotspot emission, two RM component models are strongly favoured over a single RM component, and the best-fitting model requires Faraday dispersions of approximately 0.7 and 1.2 rad m −2 (with a mean RM of ∼50 rad m −2 ). High resolution imaging at 5 ′′ with the ATCA shows significant sub-structure in the southern hotspot and highlights some of the limitations in the polarization modelling of the MWA data. Based on the observed depolarization, combined with extrapolations of gas density scaling-relations for group environments, we estimate magnetic field strengths in the intergalactic medium between ∼0.04 and 0.5 µG. We also comment on future prospects of detecting more polarized sources at low frequencies.

show abstract

Magnetic field strengths in the hotspots of 3C 33 and 111

Cited by 51 publications

References 25 publications

An X-ray survey of the 2 Jy sample – II. X-ray emission from extended structures

An X-ray survey of the 2 Jy sample – II. X-ray emission from extended structures

Magnetic Fields in Astrophysical Jets: From Launch to Termination

Faraday rotation at low frequencies: magnetoionic material of the large FRII radio galaxy PKS J0636−2036

Contact Info

Product

Resources

About