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
Radiation processes in the Seyfert galaxy NGC 4151
Blekinge Institute of Technology, School of Engineering, Department of Mathematics and Natural Sciences.
2012 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 547Article in journal (Refereed) Published
Abstract [en]

Aims. The main aim of this work was to investigate if the radiative process photoexcitation by accidental resonance (PAR) is producing Fe II lines in the UV region of NGC 4151. At the same time I searched for collisionally excited Fe II emission. While doing so, the broad line region (BLR), intermediate line region (ILR) and narrow line region (NLR) contributions to the Mg II resonance doublet were also investigated. Methods. The focus was on the 2000 to 3000 Å wavelength region, in which decay from both the collisionally and PAR excited Fe II levels would form emission lines. I examined three archived Space Telescope Imaging Spectrograph (STIS) spectra of NGC 4151. Theoretical spectra based on calculated ranges for possible fluxes of the collisionally excited lines and pumping rates through the Fe II channels were then fitted to the observed spectra Results. I show that the UV region is influenced by PAR and that the Fe II fluorescence lines are clearly needed to explain the spectrum between 2000 to 3000 Å. The best fit of the theoretical spectra to the STIS spectra was obtained by assuming a similar radiation power of Fe+ ions and Mg+ ions. Conclusions. The PAR is active in the BLR of NGC 4151 and the total power of the Fe II fluorescence is a significant fraction of the total emission in the 2000 to 3000 wavelength region. Therefore it is important to incorporate this in models of NGC 4151 and possibly also in models of other active galactic nuclei. There are also many collisionally excited Fe II lines that are blended by each other and are therefore not individually observable in the NGC 4151 spectra.

Place, publisher, year, edition, pages
Springer , 2012. Vol. 547
Keywords [en]
atomic processes, line formation, active galaxies, NGC4151
National Category
Mathematical Analysis
Identifiers
URN: urn:nbn:se:bth-7033DOI: 10.1051/0004-6361/201220248Local ID: oai:bth.se:forskinfo53D10264F1A51731C1257AF5003D12D0OAI: oai:DiVA.org:bth-7033DiVA, id: diva2:834608
Available from: 2013-01-17 Created: 2013-01-16 Last updated: 2017-12-04Bibliographically approved

Open Access in DiVA

fulltext(240 kB)797 downloads
File information
File name FULLTEXT01.pdfFile size 240 kBChecksum SHA-512
efe8b551317e84b04d032eba97b7d594601867f2f525b805ad4c68a58bc90ef8532c7d76675d5fde5b9a6aefb6dfb780e226dcd8e7d343977bb3c604137e5470
Type fulltextMimetype application/pdf

Other links

Publisher's full text

Authority records

Eriksson, Mattias

Search in DiVA

By author/editor
Eriksson, Mattias
By organisation
Department of Mathematics and Natural Sciences
In the same journal
Astronomy and Astrophysics
Mathematical Analysis

Search outside of DiVA

GoogleGoogle Scholar
Total: 797 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 638 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