Locating the gamma-ray emission site in Fermi/LAT blazars: II. Multifrequency correlations

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

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en

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10

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Monthly Notices of the Royal Astronomical Society, Volume 456, issue 1, pp. 171-180

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In an attempt to constrain and understand the emission mechanism of. gamma-rays, we perform a cross-correlation analysis of 15 blazars using light curves inmillimetre, optical and gamma-rays. We use discrete correlation function and consider only correlations significant at the 99 per cent level. A strong correlation was found between 37 and 95 GHz with a near-zero time delay in most of the sources, and similar to 1 month or longer in the rest. A similar result was obtained between the optical and. gamma-ray bands. Of the 15 sources, less than 50 per cent showed a strong correlation between the millimetre and gamma-ray or millimetre and optical bands. The primary reason for the lack of statistically significant correlation is the absence of a major outburst in the millimetre bands of most of the sources during the 2.5 yr time period investigated in our study. This may indicate that only the long-term variations or large flares are correlated between these bands. The variability of the sources at every waveband was also inspected using fractional rms variability (F-var ). The F-var displays an increase with frequency reaching its maximum in the gamma-rays.

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VK: BIBCODE: 2016MNRAS.456..171R; DOI: 10.1093/mnras/stv2653;; eprintid: arXiv:1511.02654

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Ramakrishnan, V, Hovatta, T, Tornikoski, M, Nilsson, K, Lindfors, E, Balokovic, M, Lähteenmäki, A, Reinthal, R & Takalo, L 2016, 'Locating the gamma-ray emission site in Fermi/LAT blazars : II. Multifrequency correlations', Monthly Notices of the Royal Astronomical Society, vol. 456, no. 1, pp. 171-180. https://doi.org/10.1093/mnras/stv2653