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

The bright type I Seyfert galaxy NGC 3516 was observed by {\it Suzaku} twice,in 2005 October 12--15 and 2009 October 28--November 2, for a gross timecoverage of 242 and 544 ksec and a net exposure of 134 and 255 ksec,respectively. The 2--10 keV luminosity was $2.8 \times 10^{41}$ erg s$^{-1}$ in2005, and $1.6 \times 10^{41}$ erg s$^{-1}$ in 2009. The 1.4--1.7 keV and 2--10keV count rates both exhibited peak-to-peak variations by a factor of $\sim2$in 2005, while $\sim 4$ in 2009. In either observation, the 15--45 keV countrate was less variable. The 2--10 keV spectrum in 2005 was significantly moreconvex than that in 2009. Through a count-count-plot technique, the 2--45 keVsignals in both data were successfully decomposed in a model-independent wayinto two distinct broadband components. One is a variable emission with afeatureless spectral shape, and the other is a non-varying hard componentaccompanied by a prominent Fe-K emission line at 6.33 keV (6.40 keV in the restframe). The former was fitted successfully by an absorbed power-law model,while the latter requires a new hard continuum in addition to a reflectioncomponent from distant materials. The spectral and variability differencesbetween the two observations are mainly attributed to long-term changes of thisnew hard continuum, which was stable on time scales of several hundreds ksec.

Suzaku Discovery of a Slowly Varying Hard X-ray Continuum from the Type I Seyfert Galaxy NGC 3516