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

The X-ray emission from flares on cool (i.e. spectral-type F-M) stars isindicative of very energetic, transient phenomena, associated with energyrelease via magnetic reconnection. We present a uniform, large-scale survey ofX-ray flare emission. The XMM-Newton Serendipitous Source Catalogue and itsassociated data products provide an excellent basis for a comprehensive andsensitive survey of stellar flares - both from targeted active stars and fromthose observed serendipitously in the half-degree diameter field-of-view ofeach observation. The 2XMM Catalogue and the associated time-series(`light-curve') data products have been used as the basis for a survey of X-rayflares from cool stars in the Hipparcos Tycho-2 catalogue. In addition, we havegenerated and analysed spectrally-resolved (i.e. hardness-ratio), X-raylight-curves. Where available, we have compared XMM OM UV/optical data with theX-ray light-curves. Our sample contains ~130 flares with well-observedprofiles; they originate from ~70 stars. The flares range in duration from ~1e3to ~1e4 s, have peak X-ray fluxes from ~1e-13 to ~1e-11 erg/cm2/s, peak X-rayluminosities from ~1e29 to ~1e32 erg/s, and X-ray energy output from ~1e32 to~1e35 erg. Most of the ~30 serendipitously-observed stars have littlepreviously reported information. The hardness-ratio plots clearly illustratethe spectral (and hence inferred temperature) variations characteristic of manyflares, and provide an easily accessible overview of the data. We present flarefrequency distributions from both target and serendipitous observations. Thelatter provide an unbiased (with respect to stellar activity) study of flareenergetics; in addition, they allow us to predict numbers of stellar flaresthat may be detected in future X-ray wide-field surveys. The serendipitoussample demonstrates the need for care when calculating flaring rates.

A survey of stellar X-ray flares from the XMM-Newton serendipitous source catalogue: Hipparcos-Tycho cool stars