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/

Zendy Plus

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

Zendy Tools

Zendy Open

Time-domain analysis of an archival XMM-Newton observation unveiled a veryunusual variability pattern in the soft X-ray emission of PSR J1311-3430, ablack widow millisecond pulsar in a tight binary (P_B=93.8 min) with a verylow-mass (M~0.01 Msun) He companion star, known to show flaring emission in theoptical and in the X-rays. A series of six pulses with a regular recurrencetime of ~124 min is apparent in the 0.2-10 keV light curve of the system, alsofeaturing an initial, bright flare and a quiescent phase lasting several hours.The X-ray spectrum does not change when the pulses are seen and is consistentwith a power law with photon index Gamma~1.6, also describing the quiescentemission. The peak luminosity of the pulses is of several 10^32 erg/s.Simultaneous observations in the U band with the Optical Monitor onboard XMMand in the g' band from the Las Cumbres Observatory do not show any apparentcounterpart of the pulses and only display the well-known orbital modulation ofthe system. We consider different hypotheses to explain the recurrent pulses:we investigate their possible analogy with other phenomena already observed inthis pulsar and in similar systems and we also study possible explanationsrelated to the interaction of the energetic pulsar wind with intrabinarymaterial, but we found none of these pictures to be convincing. We identifysimultaneous X-ray observations and optical spectroscopy as a possible way toconstrain the nature of the phenomenon.

A puzzling 2-hour X-ray periodicity in the 1.5-hour orbital period black widow PSR J1311-3430