J/MNRAS/508/2798 Sample of 102 distant quasars (Sotnikova+, 2021)
High-redshift quasars at z ≥ 3 - I. Radio spectra.
Sotnikova Y., Mikhailov A., Mufakharov T., Mingaliev M., Bursov N.,
Semenova T., Stolyarov V., Udovitskiy R., Kudryashova A., Erkenov A.
<Mon. Not. R. Astron. Soc., 508, 2798-2814 (2021)>
=2021MNRAS.508.2798S 2021MNRAS.508.2798S (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; Radio sources
Keywords: galaxies: active - galaxies: high-redshift - quasars: general -
radio continuum: galaxies
Abstract:
We present the radio properties of optically selected quasars with
z≥3. The complete sample consists of 102 quasars with a flux density
level S1.4≥100mJy in a declination range -35°≤Dec.≤+49°.
The observations were obtained in 2017-2020 using the radio telescope
RATAN-600. We measured flux densities at six frequencies 1.2, 2.3,
4.7, 8.2, 11.2, and 22GHz quasi-simultaneously with uncertainties of
9-31 per cent. The detection rate is 100, 89, and 46 per cent at 4.7,
11.2, and 22GHz, respectively. We have analysed the averaged radio
spectra of the quasars based on the RATAN and literature data. We
classify 46 per cent of radio spectra as peaked-spectrum, 24 per cent
as flat, and none as ultra-steep spectra (α≤-1.1). The
multifrequency data reveal that a peaked spectral shape (PS) is a
common feature for bright high-redshift quasars. This indicates the
dominance of bright compact core emission and the insignificant
contribution of extended optically thin kpc-scale components in
observed radio spectra. Using these new radio data, the radio loudness
log R was estimated for 71 objects with a median value of 3.5, showing
that the majority of the quasars are highly radio-loud with log R>2.5.
We have not found any significant correlation between z and α.
Several new megahertz- peaked spectrum (MPS) and gigahertz- peaked
spectrum (GPS) candidates are suggested. Further studies of their
variability and additional low-frequency observations are needed to
classify them precisely.
Description:
We present the radio properties of optically selected quasars with
z≥3. The complete sample consists of 102 quasars with a flux density
level S1.4≥100mJy in a declination range -35°≤Dec≤+49°.
We present two tables, one with the parameters of objects and another
table with the multifrequency (1.2, 2.3, 4.7, 8.2, 11.2, and 22GHz)
flux densities measured with RATAN-600 in 2017-2020.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 88 102 Parameters of 102 objects
table2.dat 93 1416 Flux densities
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See also:
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
J/A+A/495/691 : Multifrequency catalogue of blazars Roma-BZCAT (Massaro+, 2009)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- NVSS Name (HHMMSS+DDMMSS, J2000)
15- 18 F4.2 --- z Redshift (1)
20- 23 F4.2 Jy S4.7 Flux density at 4.7GHz
25- 28 F4.2 Jy e_S4.7 Flux density error at 4.7GHz
30- 34 F5.2 10+37W L4.7 Radio luminosity at 4.7GHz (in 1044erg/s)
36- 39 F4.2 10+37W e_L4.7 Radio luminosity error
41- 44 F4.2 --- logR ? logarithm of radio loudness
46- 49 F4.2 --- e_logR ? error of logarithm of radio loudness
51- 55 F5.2 --- Alow Spectral index in optical thick region
57- 60 F4.2 --- e_Alow Spectral index error
62- 66 F5.2 --- Ahigh Spectral index in optical thin region
68- 71 F4.2 --- e_Ahigh Spectral index error
73- 80 A8 --- SpType Spectral type: upturn, peaked, complex,
flat, steep, inverted
82- 91 A10 --- BlType Blazar type: FSRQ or blazar of uncertain
type (2)
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Note (1): From NED (NASA/IPAC Extragalactic Database)
Note (2): The blazar type according to the Roma-BZCAT catalogue 5d edition
(2009A&A...495..691M 2009A&A...495..691M, Cat. J/A+A/495/691).
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- NVSS Name (HHMMSS+DDMMSS, J2000)
15- 21 I7 --- JD Julian date
23- 27 A5 Jy S22 Flux density at 21.7/22GHz
29- 33 A5 Jy e_S22 Error of flux density at 21.7/22GHz
35- 39 A5 Jy S11 Flux density at 11.2GHz
41- 45 A5 Jy e_S11 Error of flux density at 11.2GHz
47- 51 A5 Jy S8 ? Flux density at 7.7/8.2GHz
53- 57 A5 Jy e_S8 ? Error of flux density at 7.7/8.2GHz
59- 63 A5 Jy S4 Flux density at 4.8GHz
65- 69 A5 Jy e_S4 Error of flux density at 4.8GHz
71- 75 A5 Jy S2 ? Flux density at 2.3GHz
77- 81 A5 Jy e_S2 ? Error of flux density at 2.3GHz
83- 87 A5 Jy S1 ? Flux density at 1/1.3GHz
89- 93 A5 Jy e_S1 ? Error of flux density at 1/1.3GHz
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Acknowledgements:
Yu. Sotnikova, sjv(at)sao.ru
Timur Mufakharov, timur.mufakharov(at)gmail.com
(End) Patricia Vannier [CDS] 04-Mar-2022