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 compare standard models of accretion discs around black holes (BHs) that include the appropriate zero‐torque inner boundary condition and relativistic effects on the emission and propagation of radiation. The comparison is performed adopting the multicolour disc blackbody model (MCD) as reference and looking for the parameter space in which it is in statistical agreement with ‘more physical’ accretion disc models. We find simple ‘recipes’ that can be used for adjusting the estimates of the physical inner radius of the disc, the BH mass and the accretion rate inferred using the parameters of the MCD fits. We applied these results to four ultraluminous X‐ray sources for which MCD spectral fits of their X‐ray soft spectral components have been published and find that, in three cases (NGC 1313 X‐1, X‐2 and M 81 X‐9), the BH masses inferred for a standard disc around a Schwarzschild BH are in the interval  ∼100–200 M ⊙  . Only if the BH is maximally rotating are the masses comparable to the much larger values previously derived in the literature.

A comparative analysis of standard accretion discs spectra: an application to ultraluminous X‐ray sources