J/ApJ/922/197 A large sample of FR II radio sources (Wojtowicz+, 2021)
A novel method for estimating the ambient medium density around distant radio
sources from their observed radio spectra.
Wojtowicz A., Stawarz L., Machalski J., Ostorero L.
<Astrophys. J., 922, 197 (2021)>
=2021ApJ...922..197W 2021ApJ...922..197W
ADC_Keywords: Galaxies, radio; Active gal. nuclei; Intergalactic medium
Keywords: Intergalactic medium ; Active galactic nuclei ;
Fanaroff-Riley radio galaxies ; Bayesian statistics
Abstract:
The dynamical evolution and radiative properties of luminous radio
galaxies and quasars of the FR II type, are well understood. As a
result, through the use of detailed modeling of the observed radio
emission of such sources, one can estimate various physical parameters
of the systems, including the density of the ambient medium into which
the radio structure evolves. This, however, requires rather
comprehensive observational information, i.e., sampling the broadband
radio continua of the targets at several frequencies, and imaging
their radio structures with high resolution. Such observations are, on
the other hand, not always available, especially for high-redshift
objects. Here, we analyze the best-fit values of the source physical
parameters, derived from extensive modeling of the largest currently
available sample of FR II radio sources, for which good-quality
multiwavelength radio flux measurements could be collected. In the
analyzed data set, we notice a significant and nonobvious correlation
between the spectral index of the nonthermal radio emission continuum,
and density of the ambient medium. We derive the corresponding
correlation parameters, and quantify the intrinsic scatter by means of
Bayesian analysis. We propose that the discovered correlation could be
used as a cosmological tool to estimate the density of ambient medium
for large samples of distant radio galaxies. Our method does not
require any detailed modeling of individual sources, and relies on
limited observational information, namely, the slope of the radio
continuum between the rest-frame frequencies 0.4 and 5GHz, possibly
combined with the total linear size of the radio structure.
Description:
In this paper, we explore the parameter space emerging from modeling
the largest sample of FR II radio sources selected from various radio
catalogs and surveys, namely, the Cambridge Catalogs of Radio Sources
(3C-6C-5C), the Bologna Sky Surveys (B2-B3), and the Green Bank Sky
Surveys (GB-GB2), as described extensively in
Machalski+ (2021, J/ApJS/255/22).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 86 271 *The sample of the selected 271 FRII sources with
the corresponding DYNAGE model data
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Note on table2.dat: For the modeling procedure, we use the DYNAGE algorithm of
Machalski+ (2007A&A...462...43M 2007A&A...462...43M). See Section 2.
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See also:
J/MNRAS/204/151 : Bright radio sources at 178 MHz (3CRR) (Laing+ 1983)
J/ApJS/80/501 : VLA survey of Abell clusters. II. (Owen+ 1992)
J/A+AS/128/153 : Revised GB/GB2 sample of radio sources (Machalski 1998)
J/AJ/124/1266 : Redshift survey around Abell 2199 (Rines+, 2002)
J/ApJ/658/815 : Radio loudness of active galactic nuclei (Sikora+, 2007)
J/ApJ/723/1119 : Optical properties of radio galaxies at z<0.3 (Lin+, 2010)
J/MNRAS/415/1013 : FR II radio galaxies in SDSS (Koziel-Wierzbowska+, 2011)
J/AJ/141/88 : Galaxy cluster environments of radio sources (Wing+, 2011)
J/ApJ/756/116 : FR II radio galaxies from MaxBCG (Antognini+, 2012)
J/ApJ/757/22 : Strong and weak lensing analysis of A2261 (Coe+, 2012)
J/ApJ/783/52 : Redshifts in the field of A383 (Geller+, 2014)
J/A+A/601/A81 : FIRST catalog of FR II radio galaxies (Capetti+, 2017)
J/ApJ/871/129 : A redshift catalog of the galaxy cluster A2029 (Sohn+, 2019)
J/ApJS/247/71 : Large-scale environment of radio gal. II. (Massaro+, 2020)
J/ApJS/255/22 : FRII radio sources dynamical models (Machalski+, 2021)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Source name
13- 18 F6.4 -- 1+z [1/5.42] Spectroscopic redshift
20- 27 F8.5 10+26W/Hz/sr P1.4 [0.00076/60.53] Observed power
spectral density at 1.4GHz
29- 34 F6.1 kpc Size [9.6/2451] Total linear size, D
36- 40 F5.2 --- AR [1.05/11] Aspect ratio of radio lobes
42- 48 F7.3 Myr tau [0.04/273] Jet lifetime
50- 57 F8.4 10+38W Qjet [0.0035/138] Total jet kinetic power;
10e+45erg/s
59- 65 F7.4 --- rho0a0 [0.014/37] Scaled gaseous atmosphere
central density (1)
67- 74 F8.4 10-28g/cm3 rho [0.02/886] Gas density at D/2 distance
from host galaxy center
76- 80 F5.3 --- alpInj [0.45/0.8] Injection spectral index
82- 86 F5.3 --- alpha [0.56/1.24] Lobes' radio emission
integrated spectral index (2)
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Note (1): ρ0*a0{3/2}. In units of 1e+08g/cm3/2.
Note (2): Derived from the modeled spectra between the emitted frequencies
0.4GHz and 5GHz.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 29-Mar-2023