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

We present long-term (months-years) X-ray spectral variability of the Seyfert1.8 galaxy NGC 1365 as observed by Swift, which provides well sampledobservations over a much longer timescale (6 years) and a much larger fluxrange than is afforded by other observatories. At very low luminosities thespectrum is very soft, becoming rapidly harder as the luminosity increases andthen, above a particular luminosity, softening again. At a given flux level,the scatter in hardness ratio is not very large, meaning that the spectralshape is largely determined by the luminosity. The spectra were thereforesummed in luminosity bins and fitted with a variety of models. The best fittingmodel consists of two power laws, one unabsorbed and another, more luminous,which is absorbed. In this model, we find a range of intrinsic 0.5-10.0 keVluminosities of approximately 1.1-3.5 ergs/s, and a very large range ofabsorbing columns, of approximately 10^22 - 10^24 cm^-2. Interestingly, we findthat the absorbing column decreases with increasing luminosity, but that thisresult is not due to changes in ionisation. We suggest that these observationsmight be interpreted in terms of a wind model in which the launch radius variesas a function of ionising flux and disc temperature and therefore moves outwith increasing accretion rate, i.e. increasing X-ray luminosity. Thus,depending on the inclination angle of the disc relative to the observer, theabsorbing column may decrease as the accretion rate goes up. The weaker,unabsorbed, component may be a scattered component from the wind.

Long Term Wind-Driven X-Ray Spectral Variability of NGC 1365 with Swift