Abstract
We made simultaneous single-dish and VLBI observations of a gamma-ray narrow-line Seyfert 1 (NLS1) galaxy 1H 0323+342. We found significant flux variation at 8 GHz on a time scale of one month. The total flux density varied by 5.5% in 32 days, corresponding to a variability brightness temperature of 7.0 × 1011 K. We also obtained brightness temperatures of greater than 5.2 × 1010 K from the VLBI images. These high brightness temperatures suggest that the source has nonthermal processes in the central engine. The source structure could be modelled by two elliptical Gaussian components on the parsec scales. The flux of the central component decreases in the same way as the total flux density, showing that the short-term variability is mainly associated with this component.
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Acknowledgements
The Japanese VLBI Network project is led by the National Astronomical Observatory of Japan (NAOJ), which is a branch of the National Institutes of Natural Sciences (NINS), Hokkaido University, Ibaraki University, University of Tsukuba, Gifu University, Osaka Prefecture University, Yamaguchi University and Kagoshima University, in co-operation with the Geospatial Information Authority of Japan, the Japan Aerospace Exploration Agency (JAXA), and the National Institute of Information and Communications Technology (NICT).
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Wajima, K., Fujisawa, K., Hayashida, M. et al. Japanese VLBI Network Observations of a Gamma-Ray Narrow-Line Seyfert 1 Galaxy 1H 0323+342. J Astrophys Astron 35, 215–218 (2014). https://doi.org/10.1007/s12036-014-9197-9
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DOI: https://doi.org/10.1007/s12036-014-9197-9