Astronomy and Astrophysics – Astrophysics
Scientific paper
1999-05-29
Mon.Not.Roy.Astron.Soc. 309 (1999) 1017-1033
Astronomy and Astrophysics
Astrophysics
20 pages, 7 figures, to be published in MNRAS
Scientific paper
10.1046/j.1365-8711.1999.02907.x
We have used narrow emission line data from the new 7C Redshift Survey to investigate correlations between the narrow-line luminosities and the radio properties of radio galaxies and steep-spectrum quasars. The 7C Redshift Survey is a low-frequency (151 MHz) selected sample with a flux-density limit about 25-times fainter than the 3CRR sample. By combining these samples, we can for the first time distinguish whether the correlations present are controlled by 151 MHz radio luminosity L_151 or redshift z. We find unequivocal evidence that the dominant effect is a strong positive correlation between narrow line luminosity L_NLR and L_151, of the form L_NLR proportional to L_151 ^ 0.79 +/- 0.04. Correlations of L_NLR with redshift or radio properties, such as linear size or 151 MHz (rest-frame) spectral index, are either much weaker or absent. We use simple assumptions to estimate the total bulk kinetic power Q of the jets in FRII radio sources, and confirm the underlying proportionality between jet power and narrow line luminosity first discussed by Rawlings & Saunders (1991). We make the assumption that the main energy input to the narrow line region is photoionisation by the quasar accretion disc, and relate Q to the disc luminosity, Q_phot. We find that 0.05 < Q / Q_phot < 1 so that the jet power is within about an order of magnitude of the accretion disc luminosity. The most powerful radio sources are accreting at rates close to the Eddington limit of supermassive black holes (~ 10^9 - 10^10 solar masses), whilst lower power sources are accreting at sub-Eddington rates.
Blundell Katherine M.
Lacy Mark
Rawlings Steve
Willott Chris J.
No associations
LandOfFree
The emission line - radio correlation for radio sources using the 7C Redshift Survey does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The emission line - radio correlation for radio sources using the 7C Redshift Survey, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The emission line - radio correlation for radio sources using the 7C Redshift Survey will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-330677