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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We exploit XMM-Newton archival data in a study of the extended X-ray emissionemanating from the Galactic Centre (GC) region. EPIC-pn and EPIC-MOSobservations, with a total exposure approaching 0.5 and 1 Ms respectively, wereused to create mosaiced images of a 100 pc x 100 pc region centred on Sgr A* infour bands covering the 2-10 keV energy range. We have also constructed a setof narrow-band images corresponding to the neutral iron fluorescence line at6.4 keV and the K-shell lines at 6.7 keV and 6.9 keV from helium-like andhydrogenic iron. We use a combination of spatial and spectral information todecompose the GC emission into three distinct components. These comprise: theemission from hard X-ray emitting unresolved point sources; the reflectedcontinuum and fluorescent line emission from dense molecular material; and thesoft diffuse emission from thermal plasma in the temperature range, kT ~0.8-1.5 keV.  We show that the unresolved-source component accounts for the bulk of the6.7-keV and 6.9-keV line emission. We fit the observed X-ray surface brightnessdistribution with an empirical 2-d model, which we then compare with a 3-dmass-model prediction for the old stellar population in the GC. The X-raysurface brightness falls-off more rapidly with angular offset from Sgr A* thanpredicted. One interpretation is that the 2-10 keV X-ray emissivity increasesfrom 5 x 10^27 erg s^-1 Msun^-1 at 20' up to almost twice this value at 2'.Alternatively, some refinement of the mass model may be required.  The unresolved hard X-ray emitting source population, on the basis ofspectral comparisons, is most likely dominated by magnetic CVs. We use theX-ray observations to set constraints on the number density of such sources.Our analysis does not support the conjecture that a significant fraction of thehard X-ray emission from the GC originates in very-hot diffuse thermal plasma.

XMM-Newton observations of the Galactic Centre Region - I: The distribution of low-luminosity X-ray sources