Archived
This content is available here strictly for research, reference, and/or recordkeeping and as such it may not be fully accessible. If you work or study at University of Kentucky and would like to request an accessible version, please use the SensusAccess Document Converter.
Abstract
Recent observations of quasars, Mrk 335 and the HST quasar composite spectrum, have indicated that many quasars have remarkably soft ionizing continua (f ∝ ~ ν-2, 13.6-100 eV). We point out that the number of photons with hν > 54.4 eV is insufficient to create the observed strengths of the He II emission lines. While the numbers of photons which energize C IV λ1549 and O VI λ1034 are sufficient, even the most efficiently emitting clouds for these two lines must each cover at least 20%-40% of the source. If the typical quasar ionizing continuum is indeed this soft, then we must conclude that the broad emission line clouds must see a very different (harder) continuum than we see. The other viable possibility is that the UV-EUV SED is double peaked, with the second peaking near 54 eV, its Wien tail being the observed soft X-ray excess.
Document Type
Article
Publication Date
10-1-1997
Digital Object Identifier (DOI)
http://dx.doi.org/10.1086/304659
Repository Citation
Korista, Kirk; Ferland, Gary J.; and Baldwin, Jack, "Do the Broad Emission Line Clouds See the Same Continuum That We See?" (1997). Physics and Astronomy Faculty Publications. 120.
https://uknowledge.uky.edu/physastron_facpub/120
Notes/Citation Information
Published in The Astrophysical Journal, v. 487, no. 2, p. 555-559.
© 1997. The American Astronomical Society. All rights reserved. Printed in the U.S.A.
The copyright holder has granted permission for posting the article here.