Intergalactic UV background radiation field
- 34 Downloads
We have performed proximity effect analysis of low and high resolution data, considering detailed frequency and redshift dependence of the AGN spectra processed through galactic and intergalactic material. We show that such a background flux, calculated using the observed distribution of AGNs, falls short of the value required by the proximity effect analysis by a factor of ≥ 2.7. We have studied the uncertainty in the value of the required flux due to its dependence on the resolution, description of column density distribution, systemic redshifts of QSOs etc. We conclude that in view of these uncertainties the proximity effect is consistent with the background contributed by the observed AGNs and that the hypothesized presence of an additional, dust extinct, population of AGNs may not be necessary.
Key wordsQSO absorption lines Ly α-proximity effect interga-lactic ultraviolet background radiation
Unable to display preview. Download preview PDF.
- Bechtold, J. 1995, inQSO absorption lines, ed. G. Meylan, (Springer), 299.Google Scholar
- Boksenberg, A. 1995, inQSO absorption lines, ed. G. Meylan, (Springer), 253.Google Scholar
- Giroux, M.L., Shapiro, P. R. 1996,Astrophys. J. Suppl. Ser.,461, 20.Google Scholar
- Giroux, M. L., Shull, J. M. 1997, preprint.Google Scholar
- Lanzetta, K. M., Webb, J. K., Barcons, X. 1995, inQSO absorption lines, ed. G. Meylan, (Springer), 263.Google Scholar
- Lu, L., Sargent, W. L. W., Womble, D. S., TakadaHidai, M. 1997, preprint Madau, P., Shull, J. M. 1996,Astrophys. J.,457, 551.Google Scholar
- Rauch, M., Carswell, R. F., Chaffee, F. H., Foltz, C. B., Webb, J. K., Weymann, R. F., Bechtold, J., Green, R. F. 1992,Astrophys. J.,319, 709.Google Scholar
- Steidel, C. C. 1995, inQSO absorption lines, ed. G. Meylan, (Springer), 139.Google Scholar