scholarly journals A Powerful Jet/Cloud Interaction in the Radio Galaxy PKS 2250-41

1996 ◽  
Vol 175 ◽  
pp. 227-229
Author(s):  
R. Morganti ◽  
C.N. Tadhunter ◽  
N. Clark ◽  
N. Killeen
Keyword(s):  
Emission Line ◽  
Strong Evidence ◽  
Radio Galaxy ◽  
High Redshift ◽  
Radio Galaxies ◽  
Radio Sources ◽  
Excitation Mechanism ◽  
Powerful Radio ◽  
Radio Jets ◽  
Extended Emission

Extended emission line regions aligned with the radio axis are a common feature of powerful radio galaxies and there is much interest in the origin of the extended gas and excitation mechanism. One model that can produce this alignment is photoionization by anisotropic nuclear continuum radiation. However, strong evidence exists, especially in high redshift radio galaxies, for powerful interactions between the relativistic radio jets and the ISM/IGM. Here we present the results of our study of the southern radio galaxy PKS 2250–41 (z = 0.308). This object is the most spectacular found in a sample of southern radio sources studied by Tadhunter et al. (1993) and it displays particularly clear evidence for such an interaction (Tadhunter et al. 1994; Dickson et al. 1995).

scholarly journals The Emission Line Properties of the 3CR Radio Galaxies at Redshift One: Shocks, Evolution, and the Alignment Effect

1999 ◽  
Vol 194 ◽  
pp. 241-245
Author(s):  
Philip Best ◽  
Huub Röttgering ◽  
Malcolm Longair
Keyword(s):  
Emission Line ◽  
Radio Source ◽  
Velocity Structure ◽  
Radio Galaxies ◽  
Linear Size ◽  
Continuum Emission ◽  
Radio Sources ◽  
Powerful Radio ◽  
Alignment Effect ◽  
Optical Continuum

The results of a deep spectroscopic campaign on powerful radio galaxies with redshifts z ˜ 1, to investigate in detail their emission line gas properties, are presented. Both the 2-dimensional velocity structure of the [OII] 3727 emission line and the ionisation state of the gas are found to be strongly dependent upon the linear size (age) of the radio source in a manner indicative of the emission line properties of small (young) radio sources being dominated by the passage of the radio source shocks. The consequences of this evolution throughout the few x107 year lifetime of the radio source are discussed, particularly with relation to the alignment of the UV–optical continuum emission of these objects along their radio axis, the nature of which shows similar evolution.

scholarly journals Optical Polarization of 3C 265

1996 ◽  
Vol 175 ◽  
pp. 223-226 ◽  
Author(s):  
M.H. Cohen ◽  
H.D. Tran ◽  
P.M. Ogle ◽  
R.W. Goodrich
Keyword(s):  
Emission Line ◽  
Radio Galaxy ◽  
High Redshift ◽  
Optical Polarization ◽  
Alignment Effect ◽  
Distant Galaxies ◽  
Extended Emission

3C 265 is a high-redshift (z=0.811) radio galaxy showing extended emission line regions (EELR) to 50 kpc from the nucleus (McCarthy et al 1995). However, it does not show the alignment effect (McCarthy 1993) that is common in distant galaxies: the EELR is not extended along the radio axis.

scholarly journals Weak Radio Galaxies: Narrow-Band Optical Imaging

1996 ◽  
Vol 175 ◽  
pp. 236-237
Author(s):  
René Carrillo ◽  
Irene Cruz-González
Keyword(s):  
Emission Line ◽  
Narrow Band ◽  
Radio Galaxies ◽  
Convincing Evidence ◽  
Host Galaxy ◽  
Ultraviolet Continuum ◽  
Physical Relationship ◽  
Radio Jets ◽  
Extended Radio ◽  
Extended Emission

Previous studies show that: a) radio galaxies and radio-loud quasars have emission-line gas (ELG) which is extended on scales of tenths of kiloparsecs; b) there is convincing evidence that the kinematics and excitation of the very extended emission-line gas is governed by its interaction with the outflowing radio plasma; c) the evidence for an interaction is weaker in some radio galaxies. It is argued that the ionization of the ELG may be predominantly produced by the nuclear ultraviolet continuum and the kinematics of the gas due to the gravitational potential of the host galaxy, but it is not yet known whether there is a physical relationship between the ELG and the extended radio jets.

scholarly journals Cosmological Studies from the MRC/1Jy Radio Galaxy Sample: The Spectral Index – Redshift Correlation

1999 ◽  
Vol 183 ◽  
pp. 251-251
Author(s):  
R.M. Athreya ◽  
V.K. Kapahi
Keyword(s):  
Spectral Index ◽  
Rest Frame ◽  
Radio Galaxy ◽  
High Redshift ◽  
Radio Galaxies ◽  
Linear Size ◽  
Radio Sources ◽  
Frequency Range ◽  
Galaxy Sample ◽  
Frame Frequency

The MRC/1Jy sample of 559 radio sources with S408 MHz ≥ 0.95 Jy (McCarthy et al. 1996; Kapahi et al. in preparation) is a factor of 5 to 6 times deeper than the 3CRR sample; it is therefore, well suited for disentangling the redshift (z) and luminosity (P) dependence of several properties of extragalaxtic radio sources. Here we present results on the spectral index — redshift correlation for radio galaxies, based on a comparison of the well documented radio spectra (in the rest frame frequency range of about 1 to 16 GHz) of the following two matched-luminosity samples, (a) 14 high redshift radio galaxies (HRRG) from MRC with 2.0 < z < 3.2 and linear size i > 10 kpc, and (b) 21 intermediate z radio galaxies (IRRG) from 3CRR with 0.85 < z < 1.7 and l > 10 kpc. Both samples have P1.4 GHz in the range 1028 and 1028.8 WHz−1.

scholarly journals Spatially resolved studies of extragalactic jets in high redshift radio galaxies

2014 ◽  
Vol 10 (S313) ◽  
pp. 231-235
Author(s):  
Leah K. Morabito ◽  
Adam Deller ◽  
J. B. R. Oonk ◽  
Huub Röttgering ◽  
George Miley
Keyword(s):  
High Redshift ◽  
Low Frequency ◽  
Radio Galaxies ◽  
Radio Sources ◽  
Spatially Resolved ◽  
Long Baseline ◽  
Early Results ◽  
Spectrum Radio ◽  
Extragalactic Jets ◽  
Frequency Survey

AbstractThe correlation between radio spectral steepness and redshift has been successfully used to find high redshift (z ⩾ 2) radio galaxies, but the origin of this relation is unknown. The ultra-steep spectra of high-z radio sources make them ideally suited for studies with the Low Band Antenna of the new Low Frequency Array, which covers 10–80 MHz and has baselines up to about 1300 km. As part of an ongoing survey, we use the longest baselines to map the low-frequency (< 70 MHz) spatial distributions along the jets of 5 bright extended steep spectrum high-z radio sources. From this, we will determine whether the spectra change over these spatially resolved sources, thereby constraining particle acceleration processes. We present early results from our low-frequency survey of ultra-steep spectrum radio galaxies. The first low frequency long baseline images of these objects are presented.

scholarly journals The SINFONI survey of powerful radio galaxies at z ~ 2: Jet-driven AGN feedback during the Quasar Era

2017 ◽  
Vol 599 ◽  
pp. A123 ◽  
Author(s):  
N. P. H. Nesvadba ◽  
C. De Breuck ◽  
M. D. Lehnert ◽  
P. N. Best ◽  
C. Collet
Keyword(s):  
Kinetic Energy ◽  
Interstellar Medium ◽  
Large Scale ◽  
High Redshift ◽  
Radio Galaxies ◽  
Energy Output ◽  
Host Galaxy ◽  
Powerful Radio ◽  
Massive Galaxies ◽  
Gas Kinematics

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.

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