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 transient Be/X-ray binary A0538-66 shows peculiar X-ray and opticalvariability. Despite numerous studies, the intrinsic properties underlying itsanomalous behaviour remain poorly understood. Since 2014 September we areconducting the first quasi-simultaneous optical and near-infrared photometricmonitoring of A0538-66 in seven filters with the Rapid Eye Mount (REM)telescope, aiming to understand the properties of this binary system. We foundthat the REM lightcurves show fast flares lasting one or two days that repeatalmost regularly every ~16.6 days, the orbital period of the neutron star. Ifthe optical flares are powered by X-ray outbursts through photon reprocessing,the REM lightcurves indicate that A0538-66 is still active in X-rays: brightX-ray flares (L_x > 1E37 erg/s) could be observable during the periastronpassages. The REM lightcurves show a long-term variability that is especiallypronounced in the g band and decreases with increasing wavelength, until it nolonger appears in the near-infrared lightcurves. In addition, A0538-66 isfainter with respect to previous optical observations most likely due to thehigher absorption of the stellar radiation of a denser circumstellar disc. Onthe basis of the current models, we interpret these observational results witha circumstellar disc around the Be star observed nearly edge-on during apartial depletion phase. The REM lightcurves also show short-term variabilityon timescales of ~1 day possibly indicative of perturbations in the densitydistribution of the circumstellar disc caused by the tidal interaction with theneutron star.

Optical and near-infrared photometric monitoring of the transient X-ray binary A0538-66 with REM