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 have studied the structure and energetics of the powerful microquasar/shock‐ionized nebula S26 in NGC 7793, with particular focus on its radio and X‐ray properties. Using the Australia Telescope Compact Array, we have resolved for the first time the radio lobe structure and mapped the spectral index of the radio cocoon. The steep spectral index of the radio lobes is consistent with optically‐thin synchrotron emission; outside the lobes, the spectral index is flatter, suggesting an additional contribution from free–free emission, and perhaps ongoing ejections near the core. The radio core is not detected, while the X‐ray core has a 0.3–8 keV luminosity  ≈  6 × 10 36   erg s −1  . The size of the radio cocoon matches that seen in the optical emission lines and diffuse soft X‐ray emission. The total 5.5‐GHz flux of cocoon and lobes is  ≈ 2.1 mJy, which at the assumed distance of 3.9 Mpc corresponds to about three times the luminosity of Cas A. The total 9.0‐GHz flux is  ≈ 1.6 mJy. The X‐ray hotspots (combined 0.3–8 keV luminosity  ≈  2 × 10 37   erg s −1  ) are located  ≈ 20 pc outwards of the radio hotspots (i.e. downstream along the jet direction), consistent with a different physical origin of X‐ray and radio emission (thermal‐plasma and synchrotron, respectively). The total particle energy in the bubble is ∼10 53  erg: from the observed radio flux, we estimate that only approximately a few times 10 50  erg is stored in the relativistic electrons; the rest is stored in protons, nuclei and non‐relativistic electrons. The X‐ray‐emitting component of the gas in the hotspots contains ∼10 51  erg, and ∼10 52  erg over the whole cocoon. We suggest that S26 provides a clue to understand how the ambient medium is heated by the mechanical power of a black hole near its Eddington accretion rate.

Radio lobes and X‐ray hotspots in the microquasar S26