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 a three-dimensional map of the hydrogen density distribution inthe Galactic interstellar medium. The hydrogen equivalent column densities wereobtained from the Exploring the X-ray Transient and variable Sky project ({\scEXTraS}) which provides equivalent $N_{\rm H}$ values from X-ray spectral fitsof observations within the {\it XMM-Newton} Data Release. {\sc EXTraS} includemultiple fits for each source, allowing an accurate determination of theequivalent column densities, which depends on the continuum modeling of thespectra. A cross-correlation between the {\sc EXTraS} catalogue and the first{\it Gaia} Data Release was performed in order to obtain accurate parallax anddistance measurements. We use a Bayesian method explained in \citet{rez17} inorder to predict the most probable distribution of the density at any arbitrarypoint, even for lines of sight along which there are no initial observation.The resulting map shows small-scale density structures which can not beenmodeled by using analytic density profiles. In this paper we present a proof ofconcept of the kind of science possible with the synergy of these catalogs.However, given the systematic uncertainties connected to the sourceidentification and to the dependence of $N_{\rm H}$ on the spectral model, thepresent maps should be considered qualitatively at this point.

3D mapping of the neutral X-ray absorption in the local interstellar medium: The Gaia and XMM-Newton synergy