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 Tools annual

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 monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

The 30 Dor C superbubble is unique for its synchrotron X-ray shell, as wellas being the first superbubble to be detected in TeV $\gamma$-rays, though thedominant TeV emission mechanism, i.e., leptonic or hadronic, is still unclear.We aim to use new Chandra observations of 30 Dor C to resolve the synchrotronshell in unprecedented detail and to estimate the magnetic ($B$) field in thepostshock region, a key discriminator between TeV $\gamma$-ray emissionmechanisms. We extracted radial profiles in the 1.5-8 keV range from varioussectors around the synchrotron shell and fitted these with a projected andpoint spread function convolved postshock volumetric emissivity model todetermine the filament widths. We then calculated the postshock magnetic fieldstrength from these widths. We found that most of the sectors were well fittedwith our postshock model and the determined $B$-field values were low, all withbest fits $\lesssim 20~\mu$G. Upper limits on the confidence intervals of threesectors reached $\gtrsim 30~\mu$G though these were poorly constrained. Thegenerally low $B$-field values suggests a leptonic-dominated origin for the TeV$\gamma$-rays. Our postshock model did not provide adequate fits to twosectors. We found that one sector simply did not provide a clean enough radialprofile, while the other could be fitted with a modified model where theprojected profile falls off abruptly below $\sim0.8$ times the shell radius,yielding a postshock $B$-field of 4.8 (3.7-11.8) $\mu$G which is againconsistent with the leptonic TeV $\gamma$-ray mechanism. Alternatively, theobserved profiles in these sectors could result from enhancements around ashock-cloud interaction as suggested in previous works. The average $B$-fielddetermined around the X-ray synchrotron shell of 30 Dor C suggests the leptonicscenario as the dominant emission mechanism for the TeV $\gamma$-rays.

astronomy and astrophysics

Magnetic field estimates from the X-ray synchrotron emitting rims of the  30 Dor C superbubble and the implications for the nature of 30 Dor C's TeV  emission