Multi-frequency investigation of the parsec- and kilo-parsec-scale radio structures in high-redshift quasar PKS ;1402+044
Abstract
Aims: We investigate the frequency-dependent radio properties of the jet of the luminous high-redshift (z=3.2) radio quasar PKS 1402+044 (J1405+0415) by means of radio interferometric observations.
Methods: The observational data were obtained with the VLBI Space Observatory Programme (VSOP) at 1.6 and 5 GHz, supplemented by other multi-frequency observations with the Very Long Baseline Array (VLBA; 2.3, 8.4, and 15 GHz) and the Very Large Array (VLA; 1.4, 5, 15, and 43 GHz). The observations span a period of 7 years.
Results: We find that the luminous high-redshift quasar PKS 1402+044 has a pronounced “core-jet” morphology from the parsec to the kilo-parsec scales. The jet shows a steeper spectral index and lower brightness temperature with increasing distance from the jet core. The variation of brightness temperature agrees well with the shock-in-jet model. Assuming that the jet is collimated by the ambient magnetic field, we estimate the mass of the central object as ~10^9~M_⊙. The upper limit of the jet proper motion of PKS 1402+044 is 0.03 mas yr-1 (~3c) in the east-west direction.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- October 2008
- DOI:
- 10.1051/0004-6361:200809846
- arXiv:
- arXiv:0810.0077
- Bibcode:
- 2008A&A...489..517Y
- Keywords:
-
- galaxies: individual: PKS;
- 1402+044;
- galaxies: active;
- galaxies: quasars: general;
- galaxies: jets;
- radio continuum: galaxies;
- Astrophysics
- E-Print:
- 9 pages, 6 figures,