A ten-year study of extragalactic variable sources at centimeter wavelengths

Andrew, B. H.; MacLeod, J. M.; Harvey, G. A.; Medd, W. J.

doi:10.1086/112269

Cited by 41 publications

(14 citation statements)

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“…For 0235+164 the high-frequency outburst peaking about 1982.14 is seen to peak at lower frequencies at progressively later times as indicated by the circled numbers. The amplitude of the variations increases roughly as V°' h as indicated by the solid arrow, in accord with the empirical result obtained by Andrew et al (1978) from an investigation of the variability of radio sources at high frequencies.…”

Section: Discussionsupporting

confidence: 89%

The Low Frequency Variability of Extragalactic Radio Sources

Altschuler

Dennison

Mitchell

et al. 1987

Symp. - Int. Astron. Union

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Section: Discussionsupporting

confidence: 89%

The Low Frequency Variability of Extragalactic Radio Sources

Altschuler

Dennison

Mitchell

et al. 1987

Symp. - Int. Astron. Union

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“…Observations at 2.7, 4.75 and 10.55 GHz from the 100 m telescope at Effelsberg, Germany reported in von Montigny et al (1997) were added to the 2.5 GHz, the 5 GHz and the 10 GHz light curves respectively. The 5 GHz and 10 GHz light curves also contain earlier observations at 6.6 GHz and at 10.6 GHz from the 46 m telescope of the Algonquin Radio Observatory (Medd et al 1972;Andrew et al 1978). Observations at 7.8, 7.9 and 15.5 GHz from the 37 m antenna of the Haystack Radio Observatory are included in the 10 GHz and in the 15 GHz light curves (Allen & Barrett 1966;Dent & Kapitzky 1976;Dent & Kojoian 1972;Dent et al 1974).…”

Section: Radio Observationsmentioning

confidence: 82%

30 years of multi-wavelength observations of 3C 273

Türler¹,

Paltani²,

Courvoisier³

et al. 1999

Astron. Astrophys. Suppl. Ser.

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Abstract. We present a wide multi-wavelength database of most observations of the quasar 3C 273 obtained during the last 30 years. This database is the most complete set of observations available for an active galactic nucleus (AGN). It contains nearly 20 000 observations grouped together into 70 light curves covering 16 orders of magnitude in frequency from the radio to the γ-ray domain.The database is constituted of many previously unpublished observations and of most publicly available data gathered in the literature and on the World Wide Web (WWW). It is complete to the best of our knowledge, except in the optical (UBV ) domain where we chose not to add all observations from the literature. In addition to the photometric data, we present the spectra of 3C 273 obtained by the International Ultraviolet Explorer (IUE) satellite. In the X-ray domain, we used the spectral fit parameters from the literature to construct the light curves.Apart from describing the data, we show the most representative light curves and the average spectrum of 3C 273. The database is available on the WWW in a homogeneous and clear form and we wish to update it regularly by adding new observations.Send offprint requests to: M. Türler (ISDC)

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“…Only a few active galaxies show evidence for possible periodicity in radio light curves (e.g., Raiteri et al 2001;Aller et al 2003;Kelly et al 2003;Ciaramella et al 2004;Villata et al 2004;Kadler et al 2006;Qian et al 2007;Villata et al 2009). Various mechanisms might cause a periodic appearance of outbursts in radio wavelength, such as helical movement of jet components (e.g., Camenzind & Krockenberger 1992;Villata & Raiteri 1999;Ostorero et al 2004), shock waves propagation (e.g., Gómez et al 1997), accretion disc instabilities (e.g., Honma et al 1991;Lobanov & Roland 2005), jet precession (e.g., Stirling et al 2003;Bach et al 2006;Britzen et al 2010), or they might even be indirectly caused by a secondary A&A 526, A51 (2011) MHz 1975MHz -1990 Bologna Bondi et al (1996a) 4.8 GHz 1982Michigan Aller et al (1999) 6.7 GHz 1967-1971Algonquin Medd et al (1972) 8 GHz 1970Haystack, Michigan Dent & Kapitzky (1976, Aller et al (1999) 10.7 GHz 1967-1971 Algonquin Medd et al (1972), Andrew et al (1978) 14.5 GHz 1970Haystack, Michigan Dent & Kapitzky (1974, Aller et al (1999Aller et al ( , 2003 22 GHz 1989<...>…”

Section: Introductionmentioning

confidence: 99%

A possible jet precession in the periodic quasar B0605–085

Kudryavtseva

Britzen

Witzel

et al. 2010

A&A

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Context. The quasar B0605−085 (OH 010) shows a hint for probable periodical variability in the radio total flux-density light curves. Aims. We study the possible periodicity of B0605−085 in the total flux-density, spectra, and opacity changes in order to compare it with jet kinematics on parsec scales. Methods. We have analyzed archival total flux-density variabilities at ten frequencies (408 MHz, 4.8 GHz, 6.7 GHz, 8 GHz, 10.7 GHz, 14.5 GHz, 22 GHz, 37 GHz, 90 GHz, and 230 GHz) together with the archival high-resolution very long baseline interferometry data at 15 GHz from the MOJAVE monitoring campaign. Using the Fourier transform and discrete autocorrelation methods we have searched for periods in the total flux-density light curves. In addition, spectral evolution and changes of the opacity have been analyzed. Results. We found a period in multi-frequency total flux-density light curves of 7.9 ± 0.5 yrs. Moreover, a quasi-stationary jet component C1 follows a prominent helical path on a similar timescale of eight years. We have also found that the average instantaneous speeds of the jet components show a clear helical pattern along the jet with a characteristic scale of 3 mas. Taking into account average speeds of jet components, this scale corresponds to a timescale of about 7.7 years. Jet precession can explain the helical path of the quasi-stationary jet component C1 and the periodical modulation of the total flux-density light curves. We have fitted a precession model to the trajectory of the jet component C1, with a viewing angle φ 0 = 2.6• ± 2.2 • , aperture angle of the precession cone Ω = 23.9• ± 1.9• and fixed precession period (in the observers frame) P = 7.9 yrs.

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A ten-year study of extragalactic variable sources at centimeter wavelengths

Cited by 41 publications

References 0 publications

The Low Frequency Variability of Extragalactic Radio Sources

The Low Frequency Variability of Extragalactic Radio Sources

30 years of multi-wavelength observations of 3C 273

A possible jet precession in the periodic quasar B0605–085

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