The UvA-LINKER will give you a range of other options to find the full text of a publication (including a direct link to the full-text if it is located on another database on the internet).
De UvA-LINKER biedt mogelijkheden om een publicatie elders te vinden (inclusief een directe link naar de publicatie online als deze beschikbaar is in een database op het internet).
journal id: "astrophysicalxjournal"
| Authors||E.M. Cackett, E.F. Brown, J.M. Miller, R. Wijnands|
|Title||Quiescent X-ray emission from Cen X-4: a variable thermal component|
|Faculty||Faculty of Science|
|Institute/dept.||FNWI: Astronomical Institute Anton Pannekoek (IAP)|
|Abstract||The nearby neutron star low-mass X-ray binary, Cen X-4, has been in a quiescent state since its last outburst in 1979. Typically, quiescent emission from these objects consists of thermal emission (presumably from the neutron star surface) with an additional hard power-law tail of unknown nature. Variability has been observed during quiescence in Cen X-4 on both timescales as short as hundreds of seconds and as long as years. However, the nature of this variability is still unknown. Early observations seemed to show it was all due to a variable hard X-ray tail. Here, we present new and archival observations that contradict this. The most recent Suzaku observation of Cen X-4 finds it in a historically low state, a factor of 4.4 fainter than the brightest quiescent observation. As the spectrum during the brightest observation was comprised of approximately 60% from the thermal component and 40% from the power-law component, such a large change cannot be explained by just power-law variability. Spectral fits with a variable thermal component fit the data well, while spectral fits allowing both the column density and the power law to vary do not, leading to the conclusion that the thermal component must be variable. Interestingly, we also find that the thermal fraction remains consistent between all epochs, implying that the thermal and power-law fluxes vary by approximately the same amount. If the emitting area remains unchanged between observations, then the effective surface temperature must change. Alternatively, if the temperature remains constant, then the emitting area must change. The nature of this thermal variability is unclear, but may be explained by variable low-level accretion.|
Use this url to link to this page: http://dare.uva.nl/en/record/372457
Contact us about this recordNotify a colleague
Add to bookbag