Speaker
Summary
We concentrate our efforts on the study of the correlation
between radio
galaxies/QSOs and their cores via radio luminosity functions.
Using a large
combined sample of 1100 radio-loud AGNs selected at low
radio frequency, we
investigate the radio luminosity function (RLF) at 408 MHz
band. We also
estimate the core RLF at 5 GHz band based on the 3CRR
sample and the
combined sample. Main results are follow as:
(1). In agrement with previous results, we note a strong
correlation between
core and total radio power for RGs and QSOs, but the
correlations has large
dispersion, especially for QSOs. We find that the total power
of RGs more
strongly depend on core radio power compared to QSOs.
(2). Looking at the possible existence of a redshift cut-off',
the steep-
spectrum RLFs we obtained do not show an obvious density
decline for
powerful radio sources beyond z ~ 2.5 over the whole
luminosity range, while
the density does dramatically decline at the faint end. We
argue that the
evolution of radio AGNs is luminosity-dependent and the so-
calledredshift cut-
off' may also exist in steep-spectrum population, probably at
higher redshift.
(3). The core RLFs we obtained show that the comoving
number density of
radio cores has a persistent decline with redshift, implying a
negative density
evolution. We believe that the radio core emission could be
gradually powered
by central engines, or their radio-loudness be epoch
dependent.
(4). It is noticed that the core RLF is obviously different from
the total RLF at
408 MHz band which is mainly contributed by extended
lobes, implying that the
core and extended lobes could not be co-evolving at radio
emission.
