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Extended X-ray emission around FR II radio galaxies: hotspots, lobes and galaxy clusters

Jimenez-Gallardo, Ana; Massaro, Francesco; Paggi, Alessandro; D'Abrusco, Raffaele; Prieto, M. Almudena; Peña-Herazo, Harold A.; Berta, Vittoria; Ricci, Federica; Stuardi, Chiara; Wilkes, Belinda J.; O'Dea, Christopher P.; Baum, Stefi A.; Kraft, Ralph P.; Froman, William R.; Jones, Christine; Mingo, Beatriz; Liuzzo, Elisabetta; Balmaverde, Barbara; Capetti, Alessandro; Missaglia, Valentina; Hardcastle, Martin J.; Baldi, Ranieri D.; Morabito, Leah K.

Extended X-ray emission around FR II radio galaxies: hotspots, lobes and galaxy clusters Thumbnail


Ana Jimenez-Gallardo

Francesco Massaro

Alessandro Paggi

Raffaele D'Abrusco

M. Almudena Prieto

Harold A. Peña-Herazo

Vittoria Berta

Federica Ricci

Chiara Stuardi

Belinda J. Wilkes

Christopher P. O'Dea

Stefi A. Baum

Ralph P. Kraft

William R. Froman

Christine Jones

Beatriz Mingo

Elisabetta Liuzzo

Barbara Balmaverde

Alessandro Capetti

Valentina Missaglia

Martin J. Hardcastle

Ranieri D. Baldi


We present a systematic analysis of the extended X-ray emission discovered around 35 FR II radio galaxies from the revised Third Cambridge catalog (3CR) Chandra Snapshot Survey with redshifts between 0.05 to 0.9. We aimed to (i) test for the presence of extended X-ray emission around FR II radio galaxies, (ii) investigate if the extended emission origin is due to Inverse Compton scattering of seed photons arising from the Cosmic Microwave Background (IC/CMB) or to thermal emission from an intracluster medium (ICM) and (iii) test the impact of this extended emission on hotspot detection. We investigated the nature of the extended X-ray emission by studying its morphology and compared our results with low-frequency radio observations (i.e., ∼150 MHz), in the TGSS and LOFAR archives, as well as with optical images from Pan-STARRS. In addition, we optimized a search for X-ray counterparts of hotspots in 3CR FR II radio galaxies. We found statistically significant extended emission (>3σ confidence level) along the radio axis for ∼90%, and in the perpendicular direction for ∼60% of our sample. We confirmed the detection of 7 hotspots in the 0.5 - 3 keV. In the cases where the emission in the direction perpendicular to the radio axis is comparable to that along the radio axis, we suggest that the underlying radiative process is thermal emission from ICM. Otherwise, the dominant radiative process is likely non-thermal IC/CMB emission from lobes. We found that non-thermal IC/CMB is the dominant process in ∼70% of the sources in our sample, while thermal emission from the ICM dominates in ∼15% of them.


Jimenez-Gallardo, A., Massaro, F., Paggi, A., D'Abrusco, R., Prieto, M. A., Peña-Herazo, H. A., …Morabito, L. K. (2021). Extended X-ray emission around FR II radio galaxies: hotspots, lobes and galaxy clusters. Astrophysical Journal Supplement, 252(2), Article 31.

Journal Article Type Article
Acceptance Date Oct 30, 2020
Online Publication Date Feb 5, 2021
Publication Date 2021-02
Deposit Date Jan 11, 2021
Publicly Available Date Feb 5, 2022
Journal Astrophysical Journal Supplement
Print ISSN 0067-0049
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 252
Issue 2
Article Number 31
Related Public URLs


Accepted Journal Article (8.1 Mb)

Copyright Statement
This is the Accepted Manuscript version of an article accepted for publication in The Astrophysical Journal Supplement Series. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at

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