SCATTERED NUCLEAR CONTINUUM AND BROAD H-ALPHA IN CYGNUS-A

Citation
Pm. Ogle et al., SCATTERED NUCLEAR CONTINUUM AND BROAD H-ALPHA IN CYGNUS-A, The Astrophysical journal, 482(1), 1997, pp. 37-40
Citations number
30
Categorie Soggetti
Astronomy & Astrophysics
Journal title
ISSN journal
0004637X
Volume
482
Issue
1
Year of publication
1997
Part
2
Pages
37 - 40
Database
ISI
SICI code
0004-637X(1997)482:1<37:SNCABH>2.0.ZU;2-3
Abstract
We have discovered scattered broad Balmer emission lines in the spectr um of Cygnus A, using the Keek II Telescope. Broad Her appears in pola rized flux from components on either side of the nucleus and, to a les ser extent, in the nucleus. The full-width at half-maximum of broad H alpha is 26,000 km s(-1) comparable to the widest emission lines seen in broad-line radio galaxies, Scattered active galactic nucleus light provides a significant contribution to the total flux at 3800 Angstrom (rest) of the western component, where the polarization rises to 16%. The spatially integrated flux of Cygnus A at 5500 Angstrom can be dec omposed into an elliptical galaxy fraction (F-g = 0.70), a highly pola rized blue component (FC1 = 0.15), a less polarized red component (FC = 0.09), and a contribution from the nebular continuum (0.06), Imaging polarimetry shows a double fan of polarization vectors with circular symmetry that corresponds to the ionization cone seen in Hubble Space Telescope images. Our results are consistent with scattering of light from a hidden quasar of modest luminosity by an extended, dusty narrow -line region.