J/other/A+C/25.176 NVSS and FIRST variable sources (Abrahamyan+, 2018)
Radio variable sources at 1400MHz and their optical variability.
Abrahamyan, H. V., Mickaelian, A. M., Paronyan, G. M., Mikayelyan, G. A.,
Gyulzadyan, M. V.
<Astronomy and Computing, Volume 25, p. 176-182 (2018)>
=2018A&C....25..176A 2018A&C....25..176A (SIMBAD/NED BibCode)
ADC_Keywords: Radio sources; Cross identifications; Photometry; Optical;
Active gal. nuclei
Keywords: Surveys; Catalogues; Galaxies active; BL Lac objects general;
Quasars general; Galaxies Seyfert
Abstract:
In the present study we have cross-correlated NVSS and FIRST radio
catalogues having radio flux measurements at the same 1.4GHz
frequency. This way we benefit from repeated observations from both
catalogues, as they give more accurate positions and fluxes and more
important, reveal large differences between the two measured fluxes,
thus allowing to establish radio variability. As a result 79382 radio
variables have been revealed, including 6301 with flux differences at
1.4GHz larger than 15mJy, 1917 with flux differences 45mJy and 260
with flux differences 200mJy. By using a special technique (Mickaelian
& Sinamyan 2010 (J/MNRAS/407/681) Mickaelian+ 2011 (J/MNRAS/415/1061)),
2425 optically variable objects out of 6301 radio sources have been
revealed. 2425 radio sources with both high radio and optical
variability into four categories have been divided. 1206 (19%) out of
6301 radio sources have activity types from available catalogues and
619 (25.5%) out of 2425 radio sources with at the same time radio and
optical variability have activity types from available catalogues. In
addition, 279 radio sources out of 2425 have high variability in
optical range. We have established their activity types when
available. The IR fluxes and colours for the 6301 variable radio
sources have been studied. Colour-colour diagrams show that most of
the "unknown" sources are galaxies. The activity types for 110 (42%)
out of 260 extremely high variable radio sources also have been
retrieved.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 158 6301 Variable radio sources
table8.dat 104 2425 Variable radio sources which have optical
variability
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See also:
VII/279 : SDSS quasar catalog: twelfth data release (Paris+, 2017)
VII/274 : The Roma BZCAT - 5th edition (Massaro+, 2015)
II/338 : IRAS PSC/FSC Combined Catalogue (Abrahamyan+ 2015)
VIII/92 : The FIRST Survey Catalog, Version 2014Dec17 (Helfand+ 2015)
VII/258 : Quasars and Active Galactic Nuclei (13th Ed.) (Veron+ 2010)
I/305 : The Guide Star Catalog, Version 2.3.2 (GSC2.3) (STScI, 2006)
I/284 : The USNO-B1.0 Catalog (Monet+ 2003)
I/267 : The APM-North Catalogue (McMahon+, 2000)
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
I/252 : The USNO-A2.0 Catalogue (Monet+ 1998)
J/A+A/583/A75 : Large Quasar Astrometric Catalog 3 (LQAC-3) (Souchay+, 2015)
J/ApJS/213/3 : Low-frequency flat spectrum sources (Massaro+, 2014)
J/ApJ/742/49 : FIRST var. & transient radio sources (Thyagarajan+, 2011)
J/MNRAS/415/1061 : Variability of FBS blue stellar objects (Mickaelian+ 2011)
J/ApJ/737/45 : Var. 1.4GHz radio sources from NVSS & FIRST (Ofek+, 2011)
J/MNRAS/407/681 : Proper motions of blue stellar objects (Mickaelian+, 2010)
J/ApJ/645/856 : Beamed radio-intermediate quasars (Wang+, 2006)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 F10.6 deg RAdeg FIRST right ascension (J2000)
13- 22 F10.6 deg DEdeg FIRST declination (J2000)
25- 40 A16 --- FIRST FIRST designation (JHHMMSS.s+DDMMSS)
43- 49 F7.2 mJy Fpeak [0.8/9709] FIRST peak flux density at 1.4GHz
52- 60 F9.2 mJy Fint [0.5/122194] FIRST integrated flux density
at 1.4GHz
63- 67 F5.3 mJy Rms [0.06/5.5] FIRST local noise estimate
70- 78 F9.5 deg RANdeg NVSS right ascension (J2000)
81- 89 F9.5 deg DENdeg NVSS declination (J2000)
91-103 A13 --- NVSS NVSS designation (HHMMSS+DDMMSS; J2000)
105-112 F8.1 mJy S1.4 [2.3/138487] NVSS integrated flux density
at 1.4GHz
114-119 F6.1 mJy e_S1.4 [0.4/4859] S1.4 uncertainty
122-128 F7.2 mJy del(F) [15/3099] ΔF value (1)
131-135 F5.2 -- Fr [1/67] Fr value (2)
138-150 A13 -- AT Activity Type (3)
153-158 A6 -- IAT Information on catalogues from where we
take the activity type (4)
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Note (1): We have segregated radio sources which have variability using these
formulae: (1) ΔF=|FFIRST-(FNVSS-SS)|-3K
where K is the combined positional error:
(2) K=(Error2FIRST+Error2NVSS)0.5
FFIRST and FNVSS are radio fluxes in FIRST and NVSS, ErrorFIRST
and ErrorNVSS are the errors of radio fluxes in FIRST and NVSS.
See section 2 for further explanations.
Note (2): By using formula (15), the relative variability for all sources was
counted.
(15) Fr=|(FFIRST+SS)-FNVSS|/(ErrorFIRST+ErrorNVSS)
where SS is the systematic shift between FIRST and NVSS catalogues,
FFIRST, FNVSS, ErrorFIRST and ErrorNVSS source fluxes and
their error from FIRST and NVSS catalogues.
See section 4 for further explanations.
Note (3): Activity type:
QSO = 639 occurrences
BZQ = 200 occurrences
BZB = 62 occurrences
BZG = 19 occurrences
BZU = 21 occurrences
Blazar = 4 occurrences
BLB Candidate = 1 occurrence
BL Lac = 1 occurrence
AGN = 97 occurrences
FSS = (Flat-Spectrum radio source) 87 occurrences
USS = (Ultra-Steep-Spectrum radio source) 36 occurrences
Sy 1 = 16 occurrences
Sy 1.0 = 3 occurrences
Sy 1.2 = 2 occurrences
Sy 1.5 = 6 occurrences
Sy 1.9 = 2 occurrences
Sy 2 = 9 occurrences
Starburst = 1 occurrence
Note (4): Catalogues as follows:
VCV-13 = Catalog of Quasars and Active Nuclei, 13th version
(Veron-Cetty and Veron, 2010, VII/258) -- 468 occurrences
BZCAT = Roma Multi-Frequency Catalogue of Blazars (BZCAT) 5th version
(Massaro+ 2015, VII/274) -- 303 occurrences
LQAC = Large Quasar Astrometric Catalogue 3rd Release (LQAC-3;
Souchay+ 2015, J/A+A/583/A75) -- 271 occurrences
NED = NASA Extragalactic Database (http://ned.ipac.caltech.edu/)
-- 163 occurrences
DR10Q = SDSS-DR10 Quasar Catalog (Paris+ 2014, VII/270) -- 1 occurrence
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Byte-by-byte Description of file: table8.dat
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Bytes Format Units Label Explanations
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1- 10 F10.6 deg RAdeg FIRST right ascension (J2000)
13- 22 F10.6 deg DEdeg FIRST declination (J2000)
25- 29 F5.2 mag B1 [6/24.2]? B1 (POSS1 BEST) magnitude (1)
31- 35 F5.2 mag R1 [4.5/21.1]? R1 (POSS1 BEST) magnitude (1)
37- 41 F5.2 mag B2 [6.3/23.1]? B2 (POSS2 BEST) magnitude (1)
43- 47 F5.2 mag R2 [5.3/21]? R2 (POSS2 BEST) magnitude (1)
49- 52 F4.2 mag e_B1 [0/4.6]? B1 (POSS1 BEST error) magnitude
54- 57 F4.2 mag e_R1 [0/4.5]? R1 (POSS1 BEST error) magnitude
59- 62 F4.2 mag e_B2 [0/2.5]? B2 (POSS2 BEST error) magnitude
64- 67 F4.2 mag e_R2 [0/4]? R2 (POSS2 BEST error) magnitude
70- 74 F5.2 mag del(B) [-9.7/10.4]? Difference variability ΔB
77- 82 F6.2 -- Br [0/326]? Relative variability Br
85- 91 F7.3 mag del(R) [-16.6/11.6]? Difference variability ΔR
93- 98 F6.2 -- Rr [0/220]? Relative variability Rr
101-104 I04 -- Var Variability category (2)
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Note (1): The "best magnitude" for each source from catalogues using
statistical weighting method (formulae (3)-(6)) was counted.
(3) B1Best=B1USNOA2.0*GUSNOA2.0
+B1USNOB1.0*GUSNOB1.0+bAPM*GAPM
(4) R1Best=R1USNOA2.0*EUSNOA2.0
+R1USNOB1.0*EUSNOB1.0+rAPM*EAPM
(5) B2Best=B2USNOB1.0*XUSNOB1.0+jGSC2.3.2*XGSC2.3.2
(6) R2Best=R2USNOB1.0*LUSNOB1.0+FGSC2.3.2*LGSC2.3.2
where G, E, X and L are the statistical weights for catalogues,
B1USNOA2.0, B1USNOB1.0, bAPM, R1USNOA2.0, R1USNOB1.0,
rAPM, B2USNOB1.0, jGSC2.3.2, R2USNOB1.0 and FGSC2.3.2
magnitudes from USNO A2.0 (Monet+ 1998, I/252),
USNO B1.0 (Monet+ 2003, I/284), APM (McMahon+ 2000, I/267) and
GSC 2.3.2 (Lasker+ 2008, I/305) catalogues.
See section 3 for further explanations.
Note (2): Variability categories based on absolute and relative magnitude
differences as given in Table 5:
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Category Delta(B) Delta(R) DeltaB & DeltaR Br & Rr
average
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1: low variability 0.10--1.44 0.10--1.49 0.10--1.47 1.50--1.99
2: medium 1.45--2.50 1.50--2.49 1.48--2.50 2.00--2.99
3: high ≥2.51 ≥2.50 ≥2.51 ≥3.00
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History:
From electronic version of the journal
Acknowledgements:
Areg Mickaelian [Byurakan Astrophysical Observatory (BAO), Armenia]
(End) Emmanuelle Perret [CDS] 18-Feb-2019