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 language | English |
|---|---|
| Pages (from-to) | 629-635 |
| Number of pages | 7 |
| Journal | Astrophysical Journal |
| Volume | 467 |
| Issue number | 2 PART I |
| Publication status | Published - 1996 |
| Externally published | Yes |
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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
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 journal › Article
}
TY - JOUR
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
UR - http://www.scopus.com/inward/record.url?scp=33749177551&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33749177551&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:33749177551
VL - 467
SP - 629
EP - 635
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2 PART I
ER -