Recently Jamrozy et al. (2009) identified 4C 02.27 (J0935+02 04) as the first possible example of a double-double radio source which is optically identified with a quasar (i.e. not a galaxy), at the redshift of z=0.649. The overall projected angular size of the radio source reaches about 1.5′, with a prominent "core" component in the centre. The two opposite pairs of radio lobes might indicate two periods of episodic activity. We report on our short exploratory 1.6-GHz Very Long Baseline Interferometry (VLBI) observations of the innermost radio structure of the quasar, conducted with the electronic European VLBI Network (e-EVN) on 2009 September 30. These revealed a milliarcsecond-scale compact source which is the base of the approaching on...
Context. There are about 60 quasars known at redshifts z > 5.7 to date. Only three of them are detec...
We report the discovery of a double–double radio source (DDRS) J0028+0035. We observed it with LOFAR...
WISE J224607.56-052634.9 (W2246-0526) is a hyperluminous (L-bol 1.7 x 10(14) L), dust-obscured, and ...
Aims. We selected two radio quasars (J1036+1326 and J1353+5725) based on their 1.4-GHz rad...
Context. The highest redshift quasars at z $\ga$ 6 receive considerable attention since they provide...
We present new high angular resolution images of the compact non-thermal radio source 4C 39.25 obtai...
An image of the nucleus of the giant quasar 4C 74.26 made using very long baseline interferometry at...
We present a deep image of the optically-powerful quasar E1821+643 at 18cm made with the Very Large ...
Context. Radio-loud active galactic nuclei in the early Universe are rare. The quasars J0906+6930 at...
We present a deep image of the optically powerful quasar E1821+643 at 18 cm made with the Very Large...
The radio source J0028+0035 is a recently discovered double-double radio galaxy at redshift z=0.398....
Observations of the radio source 4C74.26 with the Cambridge Low-Frequency Synthesis Telescope have s...
New Chandra observations of the giant (0.5 Mpc) radio galaxy 4C23.56 at z = 2.5 show X-rays in a lin...
The radio-emitting quasar SDSS J1425+3231 (z = 0.478) was recently found to have double-peaked narro...
There are about 60 quasars known at redshifts z > 5.7 to date. Only three of them are detected in th...
Context. There are about 60 quasars known at redshifts z > 5.7 to date. Only three of them are detec...
We report the discovery of a double–double radio source (DDRS) J0028+0035. We observed it with LOFAR...
WISE J224607.56-052634.9 (W2246-0526) is a hyperluminous (L-bol 1.7 x 10(14) L), dust-obscured, and ...
Aims. We selected two radio quasars (J1036+1326 and J1353+5725) based on their 1.4-GHz rad...
Context. The highest redshift quasars at z $\ga$ 6 receive considerable attention since they provide...
We present new high angular resolution images of the compact non-thermal radio source 4C 39.25 obtai...
An image of the nucleus of the giant quasar 4C 74.26 made using very long baseline interferometry at...
We present a deep image of the optically-powerful quasar E1821+643 at 18cm made with the Very Large ...
Context. Radio-loud active galactic nuclei in the early Universe are rare. The quasars J0906+6930 at...
We present a deep image of the optically powerful quasar E1821+643 at 18 cm made with the Very Large...
The radio source J0028+0035 is a recently discovered double-double radio galaxy at redshift z=0.398....
Observations of the radio source 4C74.26 with the Cambridge Low-Frequency Synthesis Telescope have s...
New Chandra observations of the giant (0.5 Mpc) radio galaxy 4C23.56 at z = 2.5 show X-rays in a lin...
The radio-emitting quasar SDSS J1425+3231 (z = 0.478) was recently found to have double-peaked narro...
There are about 60 quasars known at redshifts z > 5.7 to date. Only three of them are detected in th...
Context. There are about 60 quasars known at redshifts z > 5.7 to date. Only three of them are detec...
We report the discovery of a double–double radio source (DDRS) J0028+0035. We observed it with LOFAR...
WISE J224607.56-052634.9 (W2246-0526) is a hyperluminous (L-bol 1.7 x 10(14) L), dust-obscured, and ...