J/A+A/379/755 Radio data of X- and gamma-ray loud blazars (Venturi+, 2001)
Radio monitoring of a sample of X- and gamma-ray loud blazers.
Venturi T., Dallacasa D., Orfei A., Bondi M., Fanti C., Gregorini L.,
Mantovani F., Stanghellini C., Trigilio C., Umana G.
<Astron. Astrophys. 379, 755 (2001)>
=2001A&A...379..755V 2001A&A...379..755V (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; BL Lac objects ; Gamma rays ; X-ray sources ; Radio sources
Keywords: quasars - BL Lac objects - methods: observational
Abstract:
In this paper we present the results of a 4-year (1996-1999) radio flux
density monitoring program for a sample of X-and γ-ray loud
blazars. Our program started in January 1996 and was carried out on a
monthly basis at the frequencies of 5GHz and 8.4GHz with the 32-m
antennas located at Medicina (Bologna, Italy) and Noto (Siracusa,
Italy). 22GHz data collected at Medicina from January 1996 to June
1997 will also be presented. The sample of selected sources comprises
most radio-loud blazars with δ≥-10° characterised by
emission in the X-and γ-ray regimes, and target sources for the
BeppoSAX X-ray mission. All sources in the sample, except J1653+397
(MKN 501), are variable during the four years of our monitoring
program. We classified the type of variability in each source by means
of a structure-function analysis. We also computed the spectral index
α8.45 for all epochs with nearly simultaneous observations
at these two frequencies, and found that α8.45 starts
flattening at the very beginning of a radio flare, or flux density
increase.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 71 892 Flux density measurements
table3.tex 81 1401 LaTeX version of table3
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See also:
J/A+AS/121/119 : Gamma-ray loud blazars optical monitoring. I (Villata+ 1997)
J/A+AS/127/445 : Gamma-ray loud blazars optical monitoring. II (Raiteri+ 1998)
J/ApJ/522/846 : Optical monitoring of GeV loud blazars (Xie+, 1999)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Source Source name (JHHMM±DDMM)
11- 12 A2 --- n_Source [abc ?] Class of radio variability (1)
14- 21 A8 --- OName Other name of the source
22- 31 A10 "YYYY/MM/DD" Date1 Observing date for the 8.4GHz data
33- 37 F5.2 Jy S8.4GHz ? Flux density at 8.4GHz
39- 48 A10 "YYYY/MM/DD" Date2 Observing date for the 5GHz data
50- 54 F5.2 Jy S5GHz ? Flux density at 5GHz
56- 65 A10 "YYYY/MM/DD" Date3 Observing date for the 22GHz data
67- 71 F5.2 Jy S22GHz ? Flux density at 22GHz
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Note (1): Class of radio variability:
a: Structure functions without a clearly defined plateau.
This suggests that the time scale of the variability is longer
than the duration of our monitoring.
Examples in this class are J0530+135 and J1824+568 (4C 56.27).
b: Structure functions with both maxima and minima.
This case corresponds to recurrent variability, and the clearest
examples are J0050-094, J1419+543 (OQ 530) and J1800+784.
In all sources belonging to this class the amplitude of the
variability is similar during the four years of monitoring.
c: Structure functions with one or more plateau.
The first case, which includes for example J0238+166, identifies
sources with one single outburst, while the presence of more
than one plateau reflects the existence of different types of
variability in the same source, such as for example in J0958+655,
J1751+096 and J2253+161 (3C 454.3). In these sources short term
flux density fluctuations and longer term variations seem to
overlap. The majority of the sources in our sample belongs to
this class.
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Acknowledgements: Tiziana Venturi
(End) Patricia Bauer [CDS] 11-Sep-2001