3C-65 - OLD GALAXY OR BURIED QUASAR

Citation
M. Lacy et al., 3C-65 - OLD GALAXY OR BURIED QUASAR, Monthly Notices of the Royal Astronomical Society, 273(3), 1995, pp. 821-826
Citations number
34
Categorie Soggetti
Astronomy & Astrophysics
ISSN journal
00358711
Volume
273
Issue
3
Year of publication
1995
Pages
821 - 826
Database
ISI
SICI code
0035-8711(1995)273:3<821:3-OGOB>2.0.ZU;2-P
Abstract
3C 65 is one of the reddest known radio galaxies at z approximate to 1 . We have taken optical and near-infrared spectra, and a K-band image in an attempt to assess whether this red colour is produced by an unde rlying old stellar population. We find that the broad- and intermediat e-band fluxes are consistent with a power-law spectrum in the optical/ near-infrared, with no evidence for a 4000-Angstrom break, showing tha t the K-band light is dominated by a reddened quasar nucleus. By compa ring the optical spectral index with the mean for optically selected q uasars, we estimate an A(V) approximate to 2 towards the nucleus and a n unreddened quasar magnitude of V approximate to 19. Our spectra, how ever, do indicate the presence of a 4000-Angstrom break in the off-nuc lear light, consistent with either a formation redshift z(f) > 4 for a stellar population with a standard IMF, or the presence of young supe rgiant stars, which we have previously argued are present in the off-n uclear knot of 3C 356.