ASCA observations of the composite warm absorber in NGC 3516

G. A. Kriss, J. H. Krolik, C. Otani, B. R. Espey, T. J. Turner, T. Kh, Zlatan Tsvetanov, T. Takahashi, A. F. Davidsen, M. Tashiro, W. Zheng, S. Murakami, R. Petre, T. Mihara

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Abstract

We obtained X-ray spectra of the Seyfert 1 galaxy NGC 3516 in 1995 March using the Japanese X-ray satellite, ASCA. Simultaneous far-UV observations were obtained with the Hopkins Ultraviolet Telescope on the Astro-2 shuttle mission. The ASCA spectrum shows a lightly absorbed power law of energy index 0.78. The low-energy absorbing column is significantly less than previously seen. Prominent O vu and O VIII absorption edges are visible, but, consistent with the much lower total absorbing column, no Fe K absorption edge is detectable. A weak, narrow Fe Kα emission line from cold material is present as well as a broad Fe Kα line. These features are similar to those reported in other Seyfert 1 galaxies. A single warm absorber model provides only an imperfect description of the low-energy absorption. In addition to a highly ionized absorber with ionization parameter U = 1.66 and a total column density of 1.4 × 1022 cm-2, adding a lower ionization absorber with U = 0.32 and a total column of 6.9 × 1021 cm-2 significantly improves the fit. The contribution of resonant line scattering to our warm absorber models limits the Doppler parameter to less than 160 km s-1 at 90% confidence. Turbulence at the sound speed of the photoionized gas provides the best fit. None of the warm absorber models fitted to the X-ray spectrum can match the observed equivalent widths of all the UV absorption lines. Accounting for the X-ray and UV absorption simultaneously requires an absorbing region with a broad range of ionization parameters and column densities.

Original languageEnglish
Pages (from-to)629-635
Number of pages7
JournalAstrophysical Journal
Volume467
Issue number2 PART I
Publication statusPublished - 1996
Externally publishedYes

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absorbers
composite materials
ionization
x rays
ultraviolet telescopes
galaxies
energy
K lines
energy absorption
confidence
power law
turbulence
scattering
acoustics
gases
gas
parameter

Keywords

  • Galaxies: active
  • Galaxies: individual (NGC 3516)
  • Galaxies: nuclei
  • Galaxies: Seyfert
  • X-ray: galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Kriss, G. A., Krolik, J. H., Otani, C., Espey, B. R., Turner, T. J., Kh, T., ... Mihara, T. (1996). ASCA observations of the composite warm absorber in NGC 3516. Astrophysical Journal, 467(2 PART I), 629-635.

ASCA observations of the composite warm absorber in NGC 3516. / Kriss, G. A.; Krolik, J. H.; Otani, C.; Espey, B. R.; Turner, T. J.; Kh, T.; Tsvetanov, Zlatan; Takahashi, T.; Davidsen, A. F.; Tashiro, M.; Zheng, W.; Murakami, S.; Petre, R.; Mihara, T.

In: Astrophysical Journal, Vol. 467, No. 2 PART I, 1996, p. 629-635.

Research output: Contribution to journalArticle

Kriss, GA, Krolik, JH, Otani, C, Espey, BR, Turner, TJ, Kh, T, Tsvetanov, Z, Takahashi, T, Davidsen, AF, Tashiro, M, Zheng, W, Murakami, S, Petre, R & Mihara, T 1996, 'ASCA observations of the composite warm absorber in NGC 3516', Astrophysical Journal, vol. 467, no. 2 PART I, pp. 629-635.
Kriss GA, Krolik JH, Otani C, Espey BR, Turner TJ, Kh T et al. ASCA observations of the composite warm absorber in NGC 3516. Astrophysical Journal. 1996;467(2 PART I):629-635.
Kriss, G. A. ; Krolik, J. H. ; Otani, C. ; Espey, B. R. ; Turner, T. J. ; Kh, T. ; Tsvetanov, Zlatan ; Takahashi, T. ; Davidsen, A. F. ; Tashiro, M. ; Zheng, W. ; Murakami, S. ; Petre, R. ; Mihara, T. / ASCA observations of the composite warm absorber in NGC 3516. In: Astrophysical Journal. 1996 ; Vol. 467, No. 2 PART I. pp. 629-635.
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title = "ASCA observations of the composite warm absorber in NGC 3516",
abstract = "We obtained X-ray spectra of the Seyfert 1 galaxy NGC 3516 in 1995 March using the Japanese X-ray satellite, ASCA. Simultaneous far-UV observations were obtained with the Hopkins Ultraviolet Telescope on the Astro-2 shuttle mission. The ASCA spectrum shows a lightly absorbed power law of energy index 0.78. The low-energy absorbing column is significantly less than previously seen. Prominent O vu and O VIII absorption edges are visible, but, consistent with the much lower total absorbing column, no Fe K absorption edge is detectable. A weak, narrow Fe Kα emission line from cold material is present as well as a broad Fe Kα line. These features are similar to those reported in other Seyfert 1 galaxies. A single warm absorber model provides only an imperfect description of the low-energy absorption. In addition to a highly ionized absorber with ionization parameter U = 1.66 and a total column density of 1.4 × 1022 cm-2, adding a lower ionization absorber with U = 0.32 and a total column of 6.9 × 1021 cm-2 significantly improves the fit. The contribution of resonant line scattering to our warm absorber models limits the Doppler parameter to less than 160 km s-1 at 90{\%} confidence. Turbulence at the sound speed of the photoionized gas provides the best fit. None of the warm absorber models fitted to the X-ray spectrum can match the observed equivalent widths of all the UV absorption lines. Accounting for the X-ray and UV absorption simultaneously requires an absorbing region with a broad range of ionization parameters and column densities.",
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T1 - ASCA observations of the composite warm absorber in NGC 3516

AU - Kriss, G. A.

AU - Krolik, J. H.

AU - Otani, C.

AU - Espey, B. R.

AU - Turner, T. J.

AU - Kh, T.

AU - Tsvetanov, Zlatan

AU - Takahashi, T.

AU - Davidsen, A. F.

AU - Tashiro, M.

AU - Zheng, W.

AU - Murakami, S.

AU - Petre, R.

AU - Mihara, T.

PY - 1996

Y1 - 1996

N2 - We obtained X-ray spectra of the Seyfert 1 galaxy NGC 3516 in 1995 March using the Japanese X-ray satellite, ASCA. Simultaneous far-UV observations were obtained with the Hopkins Ultraviolet Telescope on the Astro-2 shuttle mission. The ASCA spectrum shows a lightly absorbed power law of energy index 0.78. The low-energy absorbing column is significantly less than previously seen. Prominent O vu and O VIII absorption edges are visible, but, consistent with the much lower total absorbing column, no Fe K absorption edge is detectable. A weak, narrow Fe Kα emission line from cold material is present as well as a broad Fe Kα line. These features are similar to those reported in other Seyfert 1 galaxies. A single warm absorber model provides only an imperfect description of the low-energy absorption. In addition to a highly ionized absorber with ionization parameter U = 1.66 and a total column density of 1.4 × 1022 cm-2, adding a lower ionization absorber with U = 0.32 and a total column of 6.9 × 1021 cm-2 significantly improves the fit. The contribution of resonant line scattering to our warm absorber models limits the Doppler parameter to less than 160 km s-1 at 90% confidence. Turbulence at the sound speed of the photoionized gas provides the best fit. None of the warm absorber models fitted to the X-ray spectrum can match the observed equivalent widths of all the UV absorption lines. Accounting for the X-ray and UV absorption simultaneously requires an absorbing region with a broad range of ionization parameters and column densities.

AB - We obtained X-ray spectra of the Seyfert 1 galaxy NGC 3516 in 1995 March using the Japanese X-ray satellite, ASCA. Simultaneous far-UV observations were obtained with the Hopkins Ultraviolet Telescope on the Astro-2 shuttle mission. The ASCA spectrum shows a lightly absorbed power law of energy index 0.78. The low-energy absorbing column is significantly less than previously seen. Prominent O vu and O VIII absorption edges are visible, but, consistent with the much lower total absorbing column, no Fe K absorption edge is detectable. A weak, narrow Fe Kα emission line from cold material is present as well as a broad Fe Kα line. These features are similar to those reported in other Seyfert 1 galaxies. A single warm absorber model provides only an imperfect description of the low-energy absorption. In addition to a highly ionized absorber with ionization parameter U = 1.66 and a total column density of 1.4 × 1022 cm-2, adding a lower ionization absorber with U = 0.32 and a total column of 6.9 × 1021 cm-2 significantly improves the fit. The contribution of resonant line scattering to our warm absorber models limits the Doppler parameter to less than 160 km s-1 at 90% confidence. Turbulence at the sound speed of the photoionized gas provides the best fit. None of the warm absorber models fitted to the X-ray spectrum can match the observed equivalent widths of all the UV absorption lines. Accounting for the X-ray and UV absorption simultaneously requires an absorbing region with a broad range of ionization parameters and column densities.

KW - Galaxies: active

KW - Galaxies: individual (NGC 3516)

KW - Galaxies: nuclei

KW - Galaxies: Seyfert

KW - X-ray: galaxies

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VL - 467

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EP - 635

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

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