Abstract
Spectra and scans of NGC 4151 are found to show broad lines of He I and Fe II. The He I lines are twice the width of the Balmer line wings and the broad line spectrum closely resembles that of 3C 273 Limits to the density and temperature for the region emitting the broad lines are deduced. The narrow forbidden lines are emitted in a region with log T = 4·07 ± 0·03 and density (possibly stratified) between log Ne ~ 4·3 and 3·7. How the hydrogen and helium line widths can differ is briefly discussed. Possible reasons for the difference between quasars and Seyferts with Fe II emission and those with strong forbidden line spectra are advanced.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
