2004A&A...419..485C


Query : 2004A&A...419..485C

2004A&A...419..485C - Astronomy and Astrophysics, volume 419, 485-500 (2004/5-4)

A multifrequency analysis of radio variability of blazars.

CIARAMELLA A., BONGARDO C., ALLER H.D., ALLER M.F., DE ZOTTI G., LAEHTEENMAEKI A., LONGO G., MILANO L., TAGLIAFERRI R., TERAESRANTA H., TORNIKOSKI M. and URPO S.

Abstract (from CDS):

We have carried out a multifrequency analysis of the radio variability of blazars, exploiting the data obtained during the extensive monitoring programs carried out at the University of Michigan Radio Astronomy Observatory (UMRAO, at 4.8, 8, and 14.5GHz) and at the Metsaehovi Radio Observatory (22 and 37GHz). Two different techniques detect, in the Metsaehovi light curves, evidence of periodicity at both frequencies for 5 sources (0224+671, 0945+408, 1226+023, 2200+420, and 2251+158). For the last three sources, consistent periods are found also at the three UMRAO frequencies and the Scargle (1982) method yields an extremely low false-alarm probability. On the other hand, the 22 and 37GHz periodicities of 0224+671 and 0945+408 (which were less extensively monitored at Metsaehovi and for which we get a significant false-alarm probability) are not confirmed by the UMRAO database, where some indications of ill-defined periods of about a factor of two longer are retrieved. We have also investigated the variability index, the structure function, and the distribution of intensity variations of the most extensively monitored sources. We find a statistically significant difference in the distribution of the variability index for BL Lac objects compared to flat-spectrum radio quasars (FSRQs), in the sense that the former objects are more variable. For both populations the variability index steadily increases with increasing frequency. The distribution of intensity variations also broadens with increasing frequency, and approaches a log-normal shape at the highest frequencies. We find that variability enhances by 20-30% the high frequency counts of extragalactic radio-sources at bright flux densities, such as those of the WMAP and Planck surveys. In all objects with detected periodicity we find evidence for the existence of impulsive signals superimposed on the periodic component.

Abstract Copyright:

Journal keyword(s): radiation mechanisms: non-thermal - methods: statistical - galaxies: BL Lacertae objects: general - active - radio continuum: galaxies: general

Simbad objects: 40

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Number of rows : 40
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 QSO B0048-09 BLL 00 50 41.3172421464 -09 29 05.210474100 16.74 16.39 16.22 16.14   ~ 443 2
2 QSO B0133+476 Bla 01 36 58.59480326 +47 51 29.1000720     19.50 19.25 15.21 ~ 479 1
3 4C 15.05 Bla 02 04 50.41389294 +15 14 11.0436097   21.9 21.00 21.00   ~ 393 1
4 4C 67.05 QSO 02 28 50.05148365 +67 21 03.0293322   19.5 19.50 18.1   ~ 243 1
5 QSO B0235+1624 BLL 02 38 38.93010450 +16 36 59.2745528   16.46 15.50 15.92   ~ 1488 2
6 QSO B0420-0127 QSO 04 23 15.80072217 -01 20 33.0656073   17.50 17.00 16.28   ~ 1163 3
7 Mrk 1506 Sy1 04 33 11.0956735296 +05 21 15.619461552   15.72 15.05 10.08   ~ 1963 2
8 QSO B0605-0834 BLL 06 07 59.69924014 -08 34 49.9783246     17.60 17.70   ~ 436 1
9 QSO B0607-157 QSO 06 09 40.94954062 -15 42 40.6727537   18.47 18.00 19.90   ~ 306 1
10 QSO J0738+1742 BLL 07 38 07.39375312 +17 42 18.9981506   16.76 16.22 15.78   ~ 961 1
11 7C 081451.89+423206.00 BLL 08 18 15.99961476 +42 22 45.4148987   18.88 18.18 17.81   ~ 382 1
12 QSO J0854+2006 BLL 08 54 48.8749846272 +20 06 30.639583620   15.91 15.43 15.56   ~ 2243 1
13 ICRF J092703.0+390220 Sy1 09 27 03.01394144 +39 02 20.8518067   17.17 17.00 16.486   ~ 977 1
14 4C 40.24 QSO 09 48 55.33815103 +40 39 44.5869471   18.31 18.02 17.85   ~ 332 1
15 6C 095456+654857 BLL 09 58 47.2451872176 +65 33 54.819354600     17.0 15.75   ~ 672 1
16 QSO B1034-293 QSO 10 37 16.07974265 -29 34 02.8134977   16.46 16.46 17.54   ~ 312 1
17 4C 01.28 BLL 10 58 29.60520810 +01 33 58.8237454   18.74 18.28 16.68   ~ 740 2
18 QSO J1130-1449 QSO 11 30 07.0523452128 -14 49 27.388021944   17.17 16.90 16 16.97 ~ 683 1
19 3C 273 BLL 12 29 06.6998257176 +02 03 08.597629980   13.05 14.830 14.11   ~ 5669 1
20 3C 279 Bla 12 56 11.16657958 -05 47 21.5251510   18.01 17.75 15.87   ~ 2950 2
21 7C 1308+3236 BLL 13 10 28.66385420 +32 20 43.7828340   15.61 15.24 17.91   ~ 820 1
22 6C 141804+543700 BLL 14 19 46.5974051952 +54 23 14.787857796   16.17 15.65 14.16   ~ 570 1
23 QSO J1512-0906 Bla 15 12 50.53293048 -09 05 59.8297908   16.74 16.54     ~ 1267 1
24 4C 14.60 BLL 15 40 49.49151924 +14 47 45.8846989   17.72 17.30 17.240   ~ 400 1
25 ICRF J163813.4+572023 Sy1 16 38 13.45629995 +57 20 23.9789828     16.90 16.94   ~ 340 1
26 4C 69.21 QSO 16 42 07.84851261 +68 56 39.7563611   19.723   19.219   ~ 295 1
27 3C 345 QSO 16 42 58.80997043 +39 48 36.9939552   16.81 16.59 16.84   ~ 1669 2
28 7C 1749+7006 BLL 17 48 32.8402992264 +70 05 50.768819304   17.46 17.01 15.48   ~ 412 1
29 4C 09.57 BLL 17 51 32.81857326 +09 39 00.7284066   17.46 16.78 15.57   ~ 907 1
30 4C 56.27 BLL 18 24 07.06837171 +56 51 01.4908155   18.9 19.30 16.48   ~ 464 1
31 4C 73.18 BLL 19 27 48.4947009120 +73 58 01.572558816     16.06 15.11   ~ 519 2
32 4C -02.81 BLL 21 34 10.30958988 -01 53 17.2389056   18.6 19.00 18.87   ~ 362 1
33 QSO B2134+0028 QSO 21 36 38.58632232 +00 41 54.2128562   17.30 17.08 17.02   ~ 553 2
34 4C 06.69 QSO 21 48 05.45866779 +06 57 38.6041877   16.85 16.47 15.06   ~ 648 1
35 QSO B2155-152 QSO 21 58 06.28188411 -15 01 09.3284729   18.63 18.30 17.79   ~ 311 1
36 NAME BL Lac BLL 22 02 43.2913536816 +42 16 39.979416792   15.66 14.72     ~ 2192 1
37 4C 31.63 BLL 22 03 14.9756830008 +31 45 38.269473228   15.85 15.58 14.33   ~ 485 1
38 3C 446 BLL 22 25 47.25929101 -04 57 01.3907626   18.83 18.39 16.3   ~ 807 1
39 3C 454.3 Bla 22 53 57.7480438728 +16 08 53.561508864   16.57 16.10 15.22   ~ 2753 2
40 QSO B2254+0727 BLL 22 57 17.30311778 +07 43 12.3025633   17.07 16.36     ~ 296 1

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2023.06.08-04:44:42

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