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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 (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:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 96 1958 Optical and radio data for 1958 quasars
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
Bytes Format Units Label Explanations
1- 19 A19 --- SDSS SDSS DR7 object designation (1) 21- 26 F6.4 --- z SDSS redshift from 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)
Note (1): in the format (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
History: With respect to the catalog file as published in 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)
(End) Heinz Andernach [Univ. Guanajuato], Patricia Vannier [CDS] 05-Mar-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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