Ultraviolet and optical spectra of broad-line radio galaxies
With the exception of 3C445, the narrow line ratios are similar to those obtained by Ferland and Osterbrock (1986) for active galaxies with only narrow lines. These ratios lie in the region of their Lα/Hβ vs. Hα/Hβ diagram that they associate with low intrinsic reddening (EB-V < 0.25).
The broad Lα/Hβ ratios cover a very wide range (1 – 22), and exceed the range covered by Seyfert i galaxies (2 – 15, see Wu et al. 1983). Thus the large Hβ/Hα ratio seen in BLRG (4 – 8) as compared to that in Seyferts (2.5 – 4.5) is in general not an effect of additional reddening in the BLR. If it is assumed that the intrinsic UV/optical continuum slope is similar in the BLRG, the observed W continuum flux in 3C 445 is down by at least a factor of 10. If the broad-lines were corrected for this much reddening, the intrinsic Lα/Hβ and Hα/Hβ ratios would be 12 and 5.3 respectively, which are close to the average of the ratios presented.Thus, in the specific case of 3C 445, the continuum source and BLR may indeed be heavily reddened.
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- Cassatella, A., Barbero, J., and Benvenuti, P. 1985, Astron. Astrophys., 144, 335.Google Scholar
- Ferland, G. J. and Osterbrock, D. E. 1986, Ap. J., 300, 658.Google Scholar
- Ferland, G. J., Rees, M. J., Longair, M. S., and Perryman, M. A. C. 1979, M.N.R.A.S., 187, 65P.Google Scholar
- Grandi, S. A. and Osterbrock, D. E. 1978, Ap. J., 220, 783.Google Scholar
- Oke, J. B., and Goodrich, R. W. 1981, Ap. J., 243, 445.Google Scholar
- Osterbrock, D. E., Koski, A. T., and Phillips, M. M. 1975, Ap. J., 206, 898.Google Scholar
- Wu, C. C., Boggess, A., and Gull, T. R. 1983, Ap. J., 266, 28.Google Scholar