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

While a broad profile of the Fe K$\alpha$ emission line is frequently foundin the X-ray spectra of typical Seyfert galaxies, the situation is unclear inthe case of Narrow Line Seyfert 1 galaxies (NLS1s)---an extreme subset whichare generally thought to harbor less massive black holes with higher accretionrates. In this paper, the ensemble property of the Fe K$\alpha$ line in NLS1sis investigated by stacking the X-ray spectra of a large sample of 51 NLS1sobserved with {\it XMM-Newton}. The composite X-ray spectrum reveals aprominent, broad emission feature over 4--7 keV, characteristic of the broad FeK$\alpha$ line. In addition, there is an indication for a possiblesuperimposing narrow (unresolved) line, either emission or absorption,corresponding to Fe XXVI or Fe XXV, respectively. The profile of the broademission feature can well be fitted with relativistic broad-line models, withthe line energy consistent either with 6.4 keV (i.e., neutral Fe) or with 6.67keV (i.e., highly ionized Fe), in the case of the narrow line being emissionand absorption, respectively. Interestingly, there are tentative indicationsfor low or intermediate values of the average spins of the black holes($a<0.84$), as inferred from the profile of the composite broad line. If theobserved feature is indeed a broad line rather than resulting from partialcovering absorption, our results suggest that a relativistic Fe line may infact be common in NLS1s; and there are tentative indications that black holesin NLS1s may not spin very fast in general.

monthly notices of the royal astronomical society

Relativistic Fe K$\alpha$ Line Revealed in the Composite X-ray Spectrum  of Narrow Line Seyfert 1 Galaxies --- do their black holes have averagely low  or intermediate spins?