English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We present high‐resolution 240 and 607 MHz Giant Metrewave Radio Telescope radio observations, complemented with 74 MHz archival Very Large Array radio observations of the Ophiuchus cluster of galaxies, whose radio mini‐halo has been recently detected at 1400 MHz. We also present archival  Chandra  and  XMM–Newton  data of the Ophiuchus cluster. Our observations do not show significant radio emission from the mini‐halo, hence we present upper limits to the integrated, diffuse non‐thermal radio emission of the core of the Ophiuchus cluster. The  XMM–Newton  observations can be well explained by a two‐temperature thermal model with temperatures of ≃1.8 and ≃9.0 keV, respectively, which confirms previous results that suggest that the innermost central region of the Ophiuchus cluster is a cooling core. This result is consistent with the occurrence of a mini‐halo, as expected to be found in hot clusters with cool cores. We also used the  XMM–Newton  data to set up an upper limit to the (non‐thermal) X‐ray emission from the cluster. We also emphasize that the non‐thermal X‐ray emission obtained with  XMM–Newton  and  International Gamma‐Ray Astrophysics Laboratory  ( INTEGRAL ) cannot be produced by the putative active galactic nucleus of the galaxy at the cluster centre. The combination of available radio and X‐ray data has strong implications for the currently proposed models of the spectral energy distribution (SED) from the Ophiuchus cluster. In particular, a synchrotron + inverse Compton model is in agreement with the currently available data, if the average magnetic field is in the range of 0.02–0.3 μG. A pure weakly interacting massive particle annihilation scenario can in principle reproduce both radio and X‐ray emission, but at the expense of postulating very large boost factors from dark matter substructures, jointly with extremely low values of the average magnetic field. Finally, a scenario where synchrotron and inverse Compton emission arise from PeV electron–positron pairs (via interactions with the cosmic microwave background) can be ruled out, as it predicts a non‐thermal soft X‐ray emission that largely exceeds the thermal bremsstrahlung measured by  INTEGRAL .

The origin of the diffuse non‐thermal X‐ray and radio emission in the Ophiuchus cluster of galaxies