scholarly journals Relativistic and Slowing Down: The Flow in the Hot Spots of Powerful Radio Galaxies and Quasars

2003 ◽  
Vol 589 (1) ◽  
pp. L5-L8 ◽  
Author(s):  
Markos Georganopoulos ◽  
Demosthenes Kazanas
2009 ◽  
Author(s):  
G. Migliori ◽  
P. Grandi ◽  
L. Angelini ◽  
L. Raimondi ◽  
E. Torresi ◽  
...  

2017 ◽  
Vol 599 ◽  
pp. A123 ◽  
Author(s):  
N. P. H. Nesvadba ◽  
C. De Breuck ◽  
M. D. Lehnert ◽  
P. N. Best ◽  
C. Collet

We present VLT/SINFONI imaging spectroscopy of the rest-frame optical emission lines of warm ionized gas in 33 powerful radio galaxies at redshifts z ≳ 2, which are excellent sites to study the interplay of rapidly accreting active galactic nuclei and the interstellar medium of the host galaxy in the very late formation stages of massive galaxies. Our targets span two orders of magnitude in radio size (2−400 kpc) and kinetic jet energy (a few 1046– almost 1048 erg s-1). All sources have complex gas kinematics with broad line widths up to ~1300 km s-1. About half have bipolar velocity fields with offsets up to 1500 km s-1 and are consistent with global back-to-back outflows. The others have complex velocity distributions, often with multiple abrupt velocity jumps far from the nucleus of the galaxy, and are not associated with a major merger in any obvious way. We present several empirical constraints that show why gas kinematics and radio jets seem to be physically related in all galaxies of the sample. The kinetic energy in the gas from large scale bulk and local outflow or turbulent motion corresponds to a few 10-3 to 10-2 of the kinetic energy output of the radio jet. In galaxies with radio jet power ≳ 1047 erg s-1, the kinetic energy in global back-to-back outflows dominates the total energy budget of the gas, suggesting that bulk motion of outflowing gas encompasses the global interstellar medium. This might be facilitated by the strong gas turbulence, as suggested by recent analytical work. We compare our findings with recent hydrodynamic simulations, and discuss the potential consequences for the subsequent evolution of massive galaxies at high redshift. Compared with recent models of metal enrichment in high-z AGN hosts, we find that the gas-phase metallicities in our galaxies are lower than in most low-z AGN, but nonetheless solar or even super-solar, suggesting that the ISM we see in these galaxies is very similar to the gas from which massive low-redshift galaxies formed most of their stars. This further highlights that we are seeing these galaxies near the end of their active formation phase.


1988 ◽  
Vol 230 (1) ◽  
pp. 131-160 ◽  
Author(s):  
R. M. Prestage ◽  
J. A. Peacock

1989 ◽  
Vol 134 ◽  
pp. 562-564
Author(s):  
G. Burbidge ◽  
A. Hewitt

In the 1950s, V.A. Ambartsumian (1958) proposed that galaxies result from explosive processes in galactic centers. Soon after the discovery of powerful radio galaxies in this same period, it became clear that explosive ejection of gas and relativistic particles was a common feature of active galaxies (Burbidge, Burbidge and Sandage 1963).


2010 ◽  
Vol 187 (1) ◽  
pp. 1-63 ◽  
Author(s):  
Ruth A. Daly ◽  
Preeti Kharb ◽  
Christopher P. O'Dea ◽  
Stefi A. Baum ◽  
Matthew P. Mory ◽  
...  

2019 ◽  
Vol 364 (10) ◽  
Author(s):  
Ilias Fernini

Abstract We report the last observational paper of hot spots for 20 Fanaroff-Riley class II (FR II) sources. These sources are part of a large sample of 98 FR II to study the unification scheme of FR II radio galaxies (RGs) and quasars (QSRs) using the hotspots (HSs) location and morphology. High-resolution VLA observations at 8.4 GHz were conducted for the whole sample. The investigation of HSs properties in FR II radio sources is essential for a better understanding of the dynamics related to the objects and their impact on the surrounding environment. HSs were classified into edged and recessed types, where the former is located at a radio lobe’s outer edge, and the latter is embedded within the lobe. The present sub-sample contains 12 RGs and 8 QSRs. Radio contour maps for each source were presented using the VLA in its A and B configurations. In total, we have identified 18 HSs for these 20 radio sources. The 12 RGs possess 8 edged HSs and 2 recessed HSs. The 8 QSRs possess 6 edged HSs and 2 recessed HSs. Out of the 14 edged HSs, RGs and QSRs possess $\sim57\%$∼57% and $\sim43\%$∼43%, respectively. A thorough morphological discussion of the 20 sources with their HSs is presented in the present work.


1989 ◽  
Vol 134 ◽  
pp. 525-528
Author(s):  
T. J. Pearson ◽  
A. C. S. Readhead

Very Long Baseline Interferometry at radio wavelengths is the only technique available for imaging the central few parsecs of powerful radio galaxies and quasars. VLBI observations have shown that in many nuclei radio-emitting material is collimated into a jet on a scale less than a parsec and ejected at relativistic velocities. The interpretation of the observations is complicated by the relativistic motion, however: the images are dominated by those parts of the source that are moving almost directly towards the observer, and thus amplified by relativistic aberration. Nonetheless, the VLBI images are vital for understanding the nature of the central engine, the cause of the collimation, and the physics of the jets.


Sign in / Sign up

Export Citation Format

Share Document