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

Transient short-period <100s oscillations have been found in the X-ray lightcurves of three novae during their SSS phase and in one persistent SSS. Wepursue an observational approach to determine possible driving mechanisms andrelations to fundamental system parameters such as the white dwarf mass.  We performed a systematic search for short-period oscillations in allavailable XMM-Newton and Chandra X-ray light curves of persistent SSS and novaeduring their SSS phase. To study time evolution, we divided each light curveinto short time segments and computed power spectra. We then constructeddynamic power spectra from which we identified transient periodic signals evenwhen only present for a short time. From all time segments of each system, wecomputed fractions of time when periodic signals were detected.  In addition to the previously known systems with short-period oscillations,RS Oph (35s), KT Eri (35s), V339 Del (54s), and Cal 83 (67s), we found oneadditional system, LMC 2009a (33s), and also confirm the 35s period fromChandra data of KT Eri. The amplitudes of oscillations are of order <15% of therespective count rates and vary without any clear dependence on the X-ray countrate. The fractions of the time when the respective periods were detected at2-sigma significance (duty cycle) are 11.3%, 38.8%, 16.9%, 49.2%, and 18.7% forLMC 2009a, RS Oph, KT Eri, V339 Del, and Cal 83, respectively. The respectivehighest duty cycles found in a single observation are 38.1%, 74.5%, 61.4%,67.8%, and 61.8%.

Short-period X-ray oscillations in super-soft novae and persistent SSS