[show abstract][hide abstract] ABSTRACT: ESO422-G028 denotes the very center cD-galaxy of the giant radio source B0503-286 (Saripalli et al. 1986, Subrahmanya and Hunstead, 1986). The angular extent of the associated radio structure is about 42.4 arcmin, which corresponds to a linear size of 1.89 Mpc (with Omega_M=0.27, Omega_Lambda=0.73, and H_0=71 km/s/Mpc). Here we present new high-frequency total-power and polarization radio maps obtained with the Effelsberg 100-m dish. In addition, we correlate the radio data with optical and X-ray observations to investigate the physical conditions of both, the host galaxy and the extended structure.
[show abstract][hide abstract] ABSTRACT: We present a spectral aging study of a sample of 5 giant radio galaxies
based on radio continuum data obtained at frequencies between 326 MHz
and 10.6 GHz. Using synchrotron loss models, we determined injection
spectral indices and particle ages where possible. The results suggest
ages not older than 4*10(7) yr, a value that is typical for radio
galaxies with ``normal'' sizes. From equilibrium considerations between
lobes and jets on the one hand and the ambient medium on the other we
derived estimates of the density of the intergalactic medium, with
average values in the range of a few 10(-5) cm(-3) .
Astronomy and Astrophysics 12/1997; 329:431-442. · 5.08 Impact Factor
[show abstract][hide abstract] ABSTRACT: We present high resolution radio observations of the nuclear radio
emission in a sample of eight radio galaxies having Megaparsec sizes,
using the European VLBI network at 18 cm. At a resolution of 25 mas we
detect all the giant radio galaxies from our sample. Among them DA 240
and 1331-099 were imaged for an extended period. These observations
reveal a twin-jet structure for DA 240 and one-sided core-jet morphology
in 1331-099. The implications of our results in the context of the
unification of quasars and powerful radio galaxies are discussed. Our
results are consistent with the suggestion that powerful radio galaxies
are the unbeamed counterparts of quasars.
Astronomy and Astrophysics 11/1997; 328:78-82. · 5.08 Impact Factor
[show abstract][hide abstract] ABSTRACT: We present 10.6GHz radio observations in total intensity and
polarization of the four radio galaxies 3C130, 1331-099, 1358+305, and
4C74.26, made with the Effelsberg 100-m telescope. These measurements
add to our sample of observations of giant radio galaxies (GRGs)
observed at λ2.8cm. The high-frequency lobe characteristics of
GRGs are reviewed. It is found that the axial ratios of the GRGs at this
wavelength do not differ significantly from those at longer wavelengths,
implying a maximum age for the GRGs of ~3x10^7^yrs. The magnetic fields
are mostly uniform over the lobes. While in some edge-brightened GRGs
the expected circumferential magnetic field is seen at the lobe
extremities, this is not the case in others. The magnetic field
structures in the lobes of asymmetric GRGs depend more on the individual
lobe structures than on the separation of the lobes from the cores.
However, a higher percentage polarization is seen in the more distant
lobes in 5 out of 7 asymmetric GRGs.
Astronomy and Astrophysics 01/1996; 306:708. · 5.08 Impact Factor
[show abstract][hide abstract] ABSTRACT: ESO 422-G028 denotes the central galaxy of the giant radio source B0503-286. Here we present new high-frequency total-power and polarization radio maps of the source obtained with the Effelsberg 100 m radio telescope. Also we correlate the radio data with optical and X-ray observations to investigate the physical conditions of the host galaxy and the extended structure.