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

Exploiting the presence of kilohertz quasi-periodic oscillations (QPOs) inthe timing power spectrum, we find that the soft x-ray emission of theneutron-star X-ray binary and atoll source 4U1636-536 modulated at the QPOfrequency lags behind that of the hard x-ray emission. Emission in the 3.8-6.4keV band is delayed by 25.0 +/- 3.3 microseconds relative to the 9.3-69 keVband. The delay increases in magnitude with increasing energy. Our results areconsistent with those of Vaughan et al. (1997), when the sign is corrected(Vaughan et al. 1998), for the atoll source 4U1608-52. The soft lag could beproduced by Comptonization of hard photons injected into a cooler electroncloud or by intrinsic spectral softening of the emission during eachoscillation cycle.Comment: Accepted to the Astrophysical Journal Letters, 4 page

Discovery of Microsecond Soft Lags in the X-Ray Emission of the Atoll Source 4U 1636−536