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

The XMM-Newton Survey Science Centre Consortium (SSC) develops software inclose collaboration with the Science Operations Centre to perform a pipelineanalysis of all XMM-Newton observations. In celebration of the 20th launchanniversary, the SSC has compiled the 4th generation of serendipitous sourcecatalogues, 4XMM. The catalogue described here, 4XMM-DR9s, explores sky areasthat were observed more than once by XMM-Newton. It was constructed fromsimultaneous source detection on the overlapping observations, which werebundled in groups ("stacks"). Stacking leads to a higher sensitivity, resultingin newly discovered sources and better constrained source parameters, andunveils long-term brightness variations. As a novel feature, positionalrectification was applied beforehand. Observations with all filters andsuitable camera settings were included. Exposures with a high background werediscarded, which was determined through a statistical analysis of all exposuresin each instrument configuration. The X-ray background maps used in sourcedetection were modelled via adaptive smoothing with newly determinedparameters. Source fluxes were derived for all contributing observations,irrespective of whether the source would be detectable in an individualobservation.  From 1,329 stacks with 6,604 contributing observations over repeatedlycovered 300 square degrees in the sky, 4XMM-DR9s lists 288,191 sources. 218,283of them were observed several times. Most stacks are composed of twoobservations, the largest one comprises 352. The number of observations of asource ranges from 1 to 40. Auxiliary products like X-ray images, long-termlight curves, and optical finding charts are published as well. 4XMM-DR9s isconsidered a prime resource to explore long-term variability of X-ray sourcesdiscovered by XMM-Newton. Regular incremental releases including new publicobservations are planned.

The XMM-Newton serendipitous survey. X: The second source catalogue from overlapping XMM-Newton observations and its long-term variable content