A longer XMM-Newton look at IZwicky 1: physical conditions and variability of the ionized absorbers

E. Costantini, L. C. Gallo, W. N. Brandt, A. C. Fabian, Th. Boller

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)

Abstract

We present a spectral analysis of the narrow-line Seyfert 1 galaxy I Zwicky 1, focusing on the characteristics of the ionized absorbers as observed with XMM-Newton in 2005. The soft X-ray spectrum shows absorption by two components of ionized gas with a similar column density (NH similar to 10(21) cm(-2)) and ionization parameters log xi similar to 0 and 2.5. Comparing this observation with a 2002 XMM-Newton data set, we see a clear anticorrelation between the X-ray ionization parameter x and the 0.1-10keV luminosity. Viable explanations for this effect include transient clouds or filaments crossing the line of sight in a complex geometry or a gas observed in non-equilibrium. The outflow velocity of the X-ray low-ionization absorber is consistent with the outflow of the ultraviolet (UV) absorber detected in a past Hubble Space Telescope observation. In addition, the ionic column densities of C IV and N V derived from the X-ray model are consistent with the UV values. This suggests that the low-ionization outflowing gas may survive for many years, despite large changes in flux, and that there is a tight connection between the X-ray and UV absorbers that can only be confirmed with a simultaneous UV and X-ray observation.

Original languageEnglish
Pages (from-to)873-880
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Volume378
DOIs
Publication statusPublished - 1 Jul 2007

Keywords

  • galaxies : individual : I Zw 1
  • quasars : absorption lines
  • galaxies : Seyfert
  • ultraviolet : galaxies
  • X-rays : galaxies
  • ACTIVE GALACTIC NUCLEI
  • SEYFERT 1 GALAXIES
  • X-RAY-ABSORPTION
  • FE-II EMISSION
  • WARM ABSORBERS
  • SIMULTANEOUS ULTRAVIOLET
  • LINE
  • NGC-5548
  • GAS
  • SPECTROSCOPY

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