scholarly journals Jet–Cloud Interactions in Compact Steep Spectrum Radio Sources

2003 ◽  
Vol 20 (1) ◽  
pp. 88-93 ◽  
Author(s):  
C. P. O'Dea ◽  
W. H. de Vries ◽  
A. M. Koekemoer ◽  
S. A. Baum ◽  
D. J. Axon ◽  
...  
Keyword(s):  
Emission Line ◽  
Radio Source ◽  
Bow Shock ◽  
Radio Sources ◽  
Line Profiles ◽  
Multiple Components ◽  
Spectrum Radio ◽  
Velocity Variations

AbstractWe have obtained HST/STIS long slit spectroscopy of the aligned emission line nebulae in three compact steep spectrum (CSS) radio sources — 3C 67, 3C 277.1, and 3C 303.1. We find systematic offsets (˜300–500 kms) of the emission line velocities on one or both sides of the radio sources. We also see evidence for broad lines (FWHM ˜500 kms) and complex emission line profiles. In 3C 303.1 the data are consistent with multiple components and possibly split lines. The amplitude of the velocity variations is not so large as to exclude gravitationally-induced motions. However, the complex kinematics, the lack of a signature of Keplerian rotation, and the association of the velocity variations with the radio lobes are consistent with the observed ˜300–500 kms velocities being driven by the expansion of the radio source. Acceleration of the clouds by the bow shock is plausible given the estimated densities in the clouds and the velocities observed in the much smaller compact symmetric objects and with expansion velocities estimated from spectral ageing. This conclusion is unchanged if we consider the scenario in which the cloud acceleration is dominated by the post bow shock flow.

scholarly journals The Milliarcsecond Core of 3C147 at 6 cm

1984 ◽  
Vol 110 ◽  
pp. 29-30 ◽  
Author(s):  
E. Preuss ◽  
W. Alef ◽  
N. Whyborn ◽  
P.N. Wilkinson ◽  
K.I. Kellermann
Keyword(s):  
Radio Source ◽  
Radio Sources ◽  
Radio Structure ◽  
Extragalactic Radio Sources ◽  
North East ◽  
The North ◽  
Vlbi Observations ◽  
Spectrum Radio ◽  
The One

3C147 is a compact (≲1″), steep spectrum radio source identified with a quasar at z = 0.545 (0″.001 = 7.4 pc; c/Ho = 6000 Mpc and qo = 0.5). The radio structure shown by VLBI observations at 18 cm (Readhead & Wilkinson, 1980; Simon et al., this volume), at 50 cm (Wilkinson et al., 1977), and at 90 cm (Simon et al., 1980 and 1983) shows a bright ‘core’ (60 pc at one end of a ‘jet’ ~0″.2 (1.5 kpc) in length oriented in p.a. ~ −130°. In this sense 3C147 is typical of the one-sided ‘core-jet’ structures commonly found in the centres of other extragalactic radio sources. However, MERLIN observations at 6 cm (Wilkinson, this vol.) and VLA observations at 2 cm (Crane & Kellermann, unpubl.; Readhead et al., 1980) show a larger elongated feature extending ~0″.5 (3.7 kpc) to the North East of the bright core in p.a. ~25° or on the opposite side to the 0″.2 jet.

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 Radio-optical Identification of Very-Steep Spectrum Radio Sources from the UTR-2 Catalogue

2002 ◽  
Vol 199 ◽  
pp. 217-218 ◽  
Author(s):  
H. Andernach ◽  
O.V. Verkhodanov ◽  
N.V. Verkhodanova
Keyword(s):  
Radio Source ◽  
High Redshift ◽  
Radio Galaxies ◽  
Image Databases ◽  
Radio Continuum ◽  
Radio Sources ◽  
Optical Identification ◽  
X Ray ◽  
Spectrum Radio

We used radio source catalogues accessible from the CATS database to establish radio continuum spectra for decametric radio sources in the UTR-2 catalogue. In an attempt to find further candidates for high-redshift radio galaxies, we searched the FIRST and NVSS surveys for counterparts of a sample of UTR sources with ultra-steep radio spectra (USS, α ≤ −1.2, S ∼ vα). We derived accurate positions and sizes for 23 of these USS sources. The search for optical counterparts from the APM (object) and DSS (image) databases, as well as infrared and X—ray identifications of these UTR sources are in progress.

scholarly journals Radio Properties of GPS and CSS Sources: Galaxies versus Quasars

2003 ◽  
Vol 20 (1) ◽  
pp. 118-122 ◽  
Author(s):  
Carlo Stanghellini
Keyword(s):  
Radio Source ◽  
Radio Sources ◽  
Spectrum Radio ◽  
The Common ◽  
The Difference

AbstractOn the basis of the different radio properties (especially different radio morphologies) between GPS galaxies and GPS quasars, I suggest that GPS galaxies are a more homogeneous class mainly consisting of compact symmetric objects, while the majority of GPS quasars are an intrinsically different type of radio source, similar to the common flat spectrum radio sources. For CSS radio sources the difference between galaxies and quasars is less evident. This is interpreted as a bias correlated with size: samples of smaller objects are more likely to be contaminated by unrelated objects. This is consistent also with the high percentage of blazar/quasar objects present in a sample of the even smaller HFP radio sources.

scholarly journals Probing multi-phase outflows and AGN feedback in compact radio galaxies: the case of PKS B1934-63

2018 ◽  
Vol 617 ◽  
pp. A139 ◽  
Author(s):  
F. Santoro ◽  
M. Rose ◽  
R. Morganti ◽  
C. Tadhunter ◽  
T. A. Oosterloo ◽  
...  
Keyword(s):  
Radio Source ◽  
Radio Sources ◽  
Ionized Gas ◽  
Near Ir ◽  
Spectrum Radio ◽  
Radial Extent ◽  
Outflow Rate ◽  
Mass Outflow ◽  
Low Efficiency ◽  
Multi Phase

Young radio AGN are pivotal for our understanding of many of the still-debated aspects of AGN feedback. In this paper we present a study of the interstellar medium (ISM) in the compact, peaked-spectrum radio galaxy PKS B1934-63 using X-shooter observations. Most of the warm ionized gas resides within a circum-nuclear disk with a radius of about 200 pc that is likely to constitute the gas reservoir from which the central black hole feeds. On the other hand, we find a biconical outflow of warm ionized gas with an estimated radius of 59 ± 12 pc. This matches the radial extent of the radio source and suggests that the outflow is jet driven. Thanks to the superior wavelength coverage of the data, we can estimate the density of the warm ionized gas using the trans-auroral line technique, and we find that the outflowing gas has remarkably high density, up to log ne (cm−3) ≃ 5.5. The estimated mass outflow rate is low (Ṁ = 10−3 −10−1 M⊙ yr−1), and the AGN feedback operates at relatively low efficiency (Ė/Lbol ∼ 10−4−10−3%). In addition, optical and near-IR line ratios show that the expansion of the radio source drives fast shocks (with velocities vs ≳ 500 km s−1) that ionize and accelerate the outflowing gas. At odds with the properties of other compact, peaked-spectrum radio sources hosting warm ionized gas outflows, we do not find signs of kinematically disturbed or outflowing gas in phases colder than the warm ionized gas. We argue that this is due to the young age of our source and thus to the recent nature of the AGN-ISM interaction, and suggest that cold gas forms within the outflowing material and the shock-ionized outflowing gas of PKS B1934-63 did not have enough time to cool down and accumulate in a colder phase. This scenario is also supported by the multi-phase outflows of other compact and young radio sources in the literature.

scholarly journals Compact Steep Spectrum Radio Sources

2002 ◽  
Vol 199 ◽  
pp. 209-210
Author(s):  
S. Jeyakumar ◽  
D. J. Saikia
Keyword(s):  
Radio Source ◽  
Radio Sources ◽  
Spectrum Radio

We suggest that most compact radio sources are young objects advancing outwards through a dense environment which is asymmetric on opposite sides of the nucleus. This gas might be intimately related to the supply of fuel for the young radio source.

scholarly journals [ITAL]Hubble Space Telescope[/ITAL] STIS Observations of the Kinematics of Emission-Line Nebulae in Three Compact Steep-Spectrum Radio Sources

2002 ◽  
Vol 123 (5) ◽  
pp. 2333-2351 ◽  
Author(s):  
Christopher P. O’Dea ◽  
Willem H. de Vries ◽  
Anton M. Koekemoer ◽  
Stefi A. Baum ◽  
Raffaella Morganti ◽  
...  
Keyword(s):  
Emission Line ◽  
Hubble Space Telescope ◽  
Radio Sources ◽  
Space Telescope ◽  
Spectrum Radio

scholarly journals Radio-Optical Correlations in Distant Radio Galaxies

1989 ◽  
Vol 134 ◽  
pp. 546-547
Author(s):  
Wil van Breugel ◽  
Patrick J. McCarthy
Keyword(s):  
Emission Line ◽  
Radio Source ◽  
Optical Emission ◽  
Radio Galaxies ◽  
Optical Observations ◽  
Radio Sources ◽  
Systematic Comparison ◽  
New Radio ◽  
Optical Identifications

Optical identifications and redshifts are now available for nearly all 3CR radio galaxies (Spinrad et al. 1985; Djorgovski et al. 1988). Using new radio and optical observations, supplemented with data from the literature, we are conducting a systematic comparison of their radio and optical (emission-line and galaxy) properties, and their dependence on redshift. Here we present new results on the alignments of galaxies and their associated radio sources, and radio source asymmetries.

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