Dielectric recombination and stability of warm gas in AGN

Susmita Chakravorty, Ajit K. Kembhavi, Martin Elvis, Gary Ferland, N. R. Badnell

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


High resolution ultraviolet and X-ray spectra show that material outflow occur from the close neighbourhoods of super-massive black holes in active galactic nuclei (AGN). The absorption features seen in the high resolution soft X-ray spectra is attributed to gas which is conventionally termed as the warm absorber (WA) and often the thermal equilibrium (stability) curve is used as a theoretical tool to offer insights into the nature of the WA. The shape of the stability curve is determined by factors like the spectral energy distribution of the ionizing flux and the chemical composition of the absorbing gas. We found that the stability curves obtained under the same set of assumptions for the prevalent physical conditions in the AGN environment, but using recently derived dielectronic recombination rates, give significantly different results from what is predicted with older atomic data. The variations in phase space region of the stability curves corresponding to WAs, lead to different physical predictions. The results obtained with the current dielectronic recombination rate coefficients are more reliable because the WA models along the stability curve have computed, updated coefficient values.

Original languageEnglish
Title of host publication17th International Conference on Atomic Processes in Plasmas, ICAPiP
Number of pages6
StatePublished - 2012
Event17th International Conference on Atomic Processes in Plasmas, ICAPiP 2011 - Belfast, United Kingdom
Duration: Jul 19 2012Jul 22 2012

Publication series

NameAIP Conference Proceedings
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


Conference17th International Conference on Atomic Processes in Plasmas, ICAPiP 2011
Country/TerritoryUnited Kingdom


  • ISM
  • ISM: lines and bands
  • atoms
  • galaxies : active
  • quasars: absorption lines

ASJC Scopus subject areas

  • Physics and Astronomy (all)


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