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J/AZh/93/605        AGN long-term variability                (Volvach+, 2016)

Long-term variability of active galactic nuclei from the "Planck" catalog. Volvach A.E., Kardashev N.S., Larionov M.G., Volvach L.N. <Astron. Zh. 93, 605 (2016)> =2016AZh....93..605V (SIMBAD/NED BibCode) =2016ARep...60..621V
ADC_Keywords: Active gal. nuclei ; Radio sources Abstract: Abstract-A complete sample of 104 bright active galactic nuclei (AGNs) from the "Planck" catalog (early results) were observed at 36.8GHz with the 22-m radio telescope of the Crimean Astrophysical Observatory (CrAO).Variability indices of the sources at this frequency were determined based on data from theWMAP space observatory, theMetsahovi RadioObservatory (Finland), and the CrimeanAstrophysical Observatory. New observational results confirm that the variability of these AGNs is stronger in the millimeter than at other radio wavelengths. The variability indices probably change as a result of the systematic decrease in the AGN flux densities in the transition to the infrared. Some radio sources demonstrate significant flux-density variations, including decreases, which sometimes cause them to fall out of the analysed sample. The change of the variability index in the millimeter is consistent with the suggestion that this variability is due to intrinsic processes in binary supermassive black holes at an evolutionary stage close to coalescence. All 104 of the sources studied are well known objects that are included in various radio catalogs and have flux densities exceeding 1Jy at 36.8GHz. Description: Observations with the 13.7-m radio telescope in Metsahovi (Finland) were carried out at 36.8GHz simultaneously with the PLANCK observations. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table.dat 81 104 Flux densities and derived spectral indices for data from Metsahovi (M), the CrAO (C), and WMAP (W)
See also: VIII/88 : Planck Early Release Compact Source Catalogue (Planck, 2011) J/A+A/581/A14 : Updated Planck catalogue PSZ1 (Planck+, 2015) J/A+A/536/A8 : Planck early results. VIII. ESZ sample. (Planck+, 2011) Byte-by-byte Description of file: table.dat
Bytes Format Units Label Explanations
1- 3 I3 --- Seq Sequential number 5- 12 A8 --- BName Source name B1950 (HHMM+DDd) 14- 22 A9 --- JName Source name J2000 (HHMM+DDMM) 25- 38 A14 --- Ident Identification 39 A1 --- n_Ident [*] Note on Ident (1) 41- 45 F5.2 Jy F36.8M Metsahovi flux density at 36.8GHz 47- 51 F5.2 Jy F36.8C CrAO flux density at 36.8GHz 53- 56 F4.2 Jy e_F36.8C rms uncertainty on F36.8C 58- 61 F4.1 Jy F36.8W ? Flux density at 36.8GHz interpolated from the WMAP data 63- 66 F4.2 Jy e_F36.8W ? Flux density at 36.8GHz 68- 70 I3 % VarM/C Metsahovi/CrAO variability index (2) 72- 76 F5.1 % VarW/C ? WMAP/CrAO variability index (3) 78- 81 F4.1 % e_VarW/C ? rms uncertainty on VarW/C
Note (1): * for sources promising for observations with the RADIOASTRON ground-space and the future MILLIMETRON mission. Note (2): The mean variability indices calculated from the Metsahovi and CrAO flux densities is 45. Note (3): The mean variability indices calculated from theWMAP and CrAO flux densities is 55.7±4.3.
History: From electronic version of the journal
(End) Patricia Vannier [CDS] 06-Dec-2016
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