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Core shift effect in blazars

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dc.contributor.author Agarwal, A
dc.contributor.author Mohan, P
dc.contributor.author Gupta, A. C
dc.contributor.author Mangalam, A
dc.contributor.author Volvach, A. E
dc.contributor.author Aller, M. F
dc.contributor.author Aller, H. D
dc.contributor.author Gu, M. F
dc.contributor.author Lahteenmaki, A
dc.contributor.author Tornikoski, M
dc.contributor.author Volvach, L. N
dc.date.accessioned 2020-11-17T14:05:42Z
dc.date.available 2020-11-17T14:05:42Z
dc.date.issued 2017-07
dc.identifier.citation Monthly Notices of the Royal Astronomical Society, Vol. 469, No. 1, pp. 813-840, en_US
dc.identifier.issn 1365-2966
dc.identifier.uri http://prints.iiap.res.in/handle/2248/7113
dc.description Restricted Access © Royal Astronomical Society https://doi.org/10.1093/mnras/stx847 en_US
dc.description.abstract We studied the pc-scale core shift effect using radio light curves for three blazars, S5 0716+714, 3C 279 and BL Lacertae, which were monitored at five frequencies (ν) between 4.8 and 36.8 GHz using the University of Michigan Radio Astronomical Observatory (UMRAO), the Crimean Astrophysical Observatory (CrAO) and Metsähovi Radio Observatory for over 40 yr. Flares were Gaussian fitted to derive time delays between observed frequencies for each flare (Δt), peak amplitude (A) and their half width. Using A ∝ να, we infer α in the range of −16.67–2.41 and using Δt∝ν1/kr⁠, we infer kr ∼ 1, employed in the context of equipartition between magnetic and kinetic energy density for parameter estimation. From the estimated core position offset (Ωrν) and the core radius (rcore), we infer that opacity model may not be valid in all cases. The mean magnetic field strengths at 1 pc (B1) and at the core (Bcore) are in agreement with previous estimates. We apply the magnetically arrested disc model to estimate black hole spins in the range of 0.15–0.9 for these blazars, indicating that the model is consistent with expected accretion mode in such sources. The power-law–shaped power spectral density has slopes −1.3 to −2.3 and is interpreted in terms of multiple shocks or magnetic instabilities. en_US
dc.language.iso en en_US
dc.publisher Oxford University Press on behalf of the Royal Astronomical Society en_US
dc.subject Galaxies: active en_US
dc.subject Quasars: individual: S5 0716+714 en_US
dc.subject 3C 279 en_US
dc.subject BL Lacertae en_US
dc.title Core shift effect in blazars en_US
dc.type Article en_US

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