J/MNRAS/466/921 Radio properties of z < 0.3 quasars (Coziol+, 2017)
What sparks the radio loud phase of nearby quasars?
Coziol R., Andernach H., Torres-Papaqui J.P., Ortega-Minakata R.A.,
Moreno del Rio F.
<Mon. Not. R. Astron. Soc. 466, 921 (2017)>
=2017MNRAS.466..921C 2017MNRAS.466..921C (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; QSOs ; Radio sources ; Surveys
Keywords: galaxies: active - quasars: spectra - quasars: radio continuum
Abstract:
To better constrain the hypotheses proposed to explain why only a few
quasars are radio loud (RL), we compare the characteristics of 1958
nearby (z≤0.3) SDSS (Sloan Digital Sky Survey) quasars, covered by
the FIRST (Faint Images of the Radio Sky at Twenty Centimeters) and
NVSS (NRAO VLA Sky Survey) radio surveys. Only 22 per cent are RL
with log(L1.4GHz)≥22.5W/Hz, the majority being compact (C), weak
radio sources (WRS), with log(L1.4GHz)<24.5W/Hz. 15 per cent of
the RL quasars have extended radio morphologies: 3 per cent have a
core and a jet (J), 2 per cent have a core with one lobe (L), and 10
per cent have a core with two lobes (T), the majority being powerful
radio sources (PRS), with log(L1.4GHz)≥24.5W/Hz. In general, RL
quasars have higher bolometric luminosities and ionization powers than
radio-quiet (RQ) quasars. The WRS have comparable black hole (BH)
masses as the RQ quasars, but higher accretion rates or radiative
efficiencies. The PRS have higher BH masses than the WRS, but
comparable accretion rates or radiative efficiencies. The WRS also
have higher FWHM_{[OIII]} than the PRS, consistent with a coupling of
the spectral characteristics of the quasars with their radio
morphologies. Inspecting the SDSS images and applying a neighbour
search algorithm reveal no difference between the RQ and RL quasars of
their host galaxies, environments, and interaction. Our results prompt
the conjecture that the phenomenon that sparks the RL phase in quasars
is transient, intrinsic to the active galactic nuclei, and stochastic,
due to the chaotic nature of the accretion process of matter on to the
BHs.
Description:
From the SDSS DR7 quasar catalog (CDS Cat. VII/260) we selected those
with redshift z≤0.3 and excluded those with Hβ line less than
1000km/s as well as spectra with deficient pixels or dubious emission
features, acquiring a final sample of 1958 quasars. SDSS spectra were
used to derive line widths of the Hβ and OIII emission lines, the
5100-Angstrom continuum luminosity as well as the Eddington ratio
Lbol/LEdd. Both visual inspection and an automated algorithm
were employed to classify and quantify the environment of the QSOs in
terms of neighboring galaxies as well as the visual morphology of the
QSOs on gri composite SDSS images. Images from the 1.4-GHz radio
surveys NVSS and FIRST, centered on the QSOs and corresponding to at
least 1Mpc in size (at the QSO redshift) were inspected, and the
radio morphology and 1.4-GHz flux densities recorded, accepting radio
detections within 2-arcsec of the QSO down to a minimum flux density
of 1.0mJy in NVSS and 0.5mJy in FIRST (approximately the 3-sigma
levels in these surveys, and two times lower than the lower flux
limits of the NVSS and FIRST source catalogues). From the integrated
flux density we derived the 1.4-GHz radio luminosity, and for extended
radio sources we catalogued the largest linear size (LLS). Three new
giant radio quasars larger than 1Mpc in projected size were found,
including the largest such example presently known, with an LLS of
4.45Mpc (H0=67.7, Ωm=0.309, ΩΛ=0.691).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 96 1958 Optical and radio data for 1958 quasars
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See also:
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
VII/260 : The SDSS-DR7 quasar catalog (Schneider+, 2010)
VIII/92 : The FIRST Survey Catalog, Version 2014Dec17 (Helfand+ 2015)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- SDSS SDSS DR7 object designation (1)
21- 26 F6.4 --- z SDSS redshift from 2010AJ....139.2360S 2010AJ....139.2360S
28- 32 I5 km/s FWHMHb Width of Hβ emission line
34- 38 F5.2 [W] lgL5100 log10 of 5100Å continuum luminosity (2)
40- 43 F4.2 [Msun] lgMBH log10 of black hole mass in solar masses (2)
45- 49 F5.2 [W] lgLbol log10 of bolometric luminosity (2)
51- 54 F4.2 --- Gamma Eddington ratio Lbol/LEdd
56- 59 I4 km/s FWHMOIII Width of the OIII emission line
61- 65 F5.2 [W] lgLOIII log10 of OIII emission-line luminosity (2)
67- 68 I2 --- N0.5 ?=- Number of neighbors within 0.5Mpc (3)
70- 71 I2 --- N1.0 ?=- Number of neighbors within 1.0Mpc (3)
73- 74 I2 --- N1.5 ?=- Number of neighbors within 1.5Mpc (3)
76- 77 A2 --- Rmorph Morphological type of radio emission (4)
79 A1 --- l_lgLrad [<] Limit flag on lgLrad
80- 84 F5.2 [W/Hz] lgLrad Monochromatic 1.4-GHz luminosity (2)
86- 89 I4 kpc LLS ?=- Largest (projected) linear size of radio
emission (2)
91 A1 --- LLSflag [FNM-] Origin of LLS (5)
93- 96 A4 --- VisClas [resib.] Result of visual inspection of
SDSS images (6)
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Note (1): in the format JHHMMSS.ss+DDMMSS.s (J2000; truncated coordinates).
Note (2): based on H0=67.7km/s/Mpc, Omegam=0.309, OmegaLambda=0.691
Note (3): a '-' sign denotes quasars for which a search for neighboring
galaxies was not possible.
Note (4): Morphological type of radio emission as follows:
C = compact
J = jet
L = jet+lobe
RU = radio undetected
T = triple
X = non classifiable (see text for details)
Note (5): Origin of LLS as follows:
F = deconvolved size of FIRST catalog source
N = deconvolved size of NVSS catalog source
M = measured on radio map (either NVSS or FIRST, whichever gave the larger
size)
Note (6): Visual inspection of SDSS images code :
bit 1 = r: well resolved
bit 2 = e: elliptical, = s: spiral
bit 3 = i: interacting or merging
bit 4 = b: brightest of its structure
any of these bits is set to "." whenever none of these flags apply
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History:
With respect to the catalog file as published in 2017MNRAS.466..921C 2017MNRAS.466..921C the
present version was corrected by H. Andernach on 03-Mar-2017 as follows:
* The cosmological parameters in Note (2) of the supplementary data in MNRAS
are incorrect. Correct values are stated on the present ReadMe.
* 160709.88+133419.0: radio luminosity moved by one byte left to align well
* 075620.07+304535.4 is detected in FIRST, classified as "C", thus
lgLrad = 22.98 (not <22.98 as in the published version)
* 105609.79+551604.0 was a misidentification and is undetected in radio,
thus Rmorph = RU, lgLrad <22.98, and no LLS nor LLSflag
* 110717.77+080438.2 was misidentified and is actually undetected in radio,
thus Rmorph = RU, lgLrad <22.75, and no LLS nor LLSflag
Acknowledgements:
Heinz Andernach, heinz(at)astro.ugto.mx
(End) Heinz Andernach [Univ. Guanajuato], Patricia Vannier [CDS] 05-Mar-2017