Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Variable spreading layer in 4U 1608-52 during thermonuclear X-ray bursts in the soft state
Stockholm University, Nordic Institute for Theoretical Physics (Nordita). University of Turku, Finland.
Show others and affiliations
Number of Authors: 5
2017 (English)In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 472, no 1, 78-89 p.Article in journal (Refereed) Published
Abstract [en]

Thermonuclear (type-I) X-ray bursts, observed from neutron star (NS) low-massX-ray binaries (LMXB), provide constraints on NS masses and radii and consequently the equation of state of NS cores. In such analyses, various assumptions are made without knowing if they are justified. We have analysed X-ray burst spectra from the LMXB 4U 1608-52, with the aim of studying how the different persistent emission components react to the bursts. During some bursts in the soft spectral state we find that there are two variable components: one corresponding to the burst blackbody component and another optically thick Comptonized component. We interpret the latter as the spreading layer between the NS surface and the accretion disc, which is not present during the hard-state bursts. We propose that the spectral changes during the soft-state bursts are driven by the spreading layer that could cover almost the entire NS in the brightest phases due to the enhanced radiation pressure support provided by the burst, and that the layer subsequently returns to its original state during the burst decay. When deriving the NS mass and radius using the soft-state bursts two assumptions are therefore not met: the NS is not entirely visible and the burst emission is reprocessed in the spreading layer, causing distortions of the emitted spectrum. For these reasons, the NS mass and radius constraints using the soft-state bursts are different compared to the ones derived using the hard-state bursts.

Place, publisher, year, edition, pages
2017. Vol. 472, no 1, 78-89 p.
Keyword [en]
stars: neutron, X-rays: binaries, X-rays: bursts
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
URN: urn:nbn:se:su:diva-148830DOI: 10.1093/mnras/stx1963ISI: 000413765800008OAI: oai:DiVA.org:su-148830DiVA: diva2:1156618
Available from: 2017-11-13 Created: 2017-11-13 Last updated: 2017-11-13Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Nättilä, Joonas
By organisation
Nordic Institute for Theoretical Physics (Nordita)
In the same journal
Monthly notices of the Royal Astronomical Society
Astronomy, Astrophysics and Cosmology

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 1 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf