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

Emission of two short hard X‐ray bursts on 2009 June 5 disclosed the existence of a new soft gamma‐ray repeater, now catalogued as SGR 0418+5729. After a few days, X‐ray pulsations at a period of 9.1 s were discovered in its persistent emission. SGR 0418+5729 was monitored almost since its discovery with the  Rossi X‐ray Timing Explorer  (2–10 keV energy range) and observed many times with  Swift  (0.2–10 keV). The source persistent X‐ray emission faded by a factor of ∼10 in about 160 d, with a steepening in the decay about 19 d after the activation. The X‐ray spectrum is well described by a simple absorbed blackbody, with a temperature decreasing in time. A phase‐coherent timing solution over the ∼160 d time‐span yielded no evidence for any significant evolution of the spin period, implying a 3σ upper limit of  1.1 × 10 −13  s s −1   on the period derivative and of  ∼3 × 10 13  G  on the surface dipole magnetic field. Phase‐resolved spectroscopy provided evidence for a significant variation of the spectrum as a function of the stellar rotation, pointing to the presence of two emitting caps, one of which became hotter during the outburst. Finally, a deep observation of the field of SGR 0418+5729 with the new Gran Telescopio Canarias 10.4‐m telescope allowed us to set an upper limit on the source optical flux of   i ′ &gt; 25.1 mag , corresponding to an X‐ray‐to‐optical flux ratio exceeding  10 4  , consistent with the characteristics of other magnetars.

Early X‐ray and optical observations of the soft gamma‐ray repeater SGR 0418+5729