Radio Emission from GRO J1655−40 during the 1994 Jet Ejection Episodes
| Autor: | D. C. Hannikainen, R. W. Hunstead, D. Campbell‐Wilson, K. Wu, D. J. McKay, D. P. Smits, R. J. Sault |
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| Rok vydání: | 2000 |
| Předmět: |
Physics
Linear polarization Astrophysics::High Energy Astrophysical Phenomena Astrophysics (astro-ph) FOS: Physical sciences Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics Light curve Polarization (waves) Synchrotron Magnetic field law.invention Telescope Space and Planetary Science law Exponential decay Molonglo Observatory Synthesis Telescope Astrophysics::Galaxy Astrophysics |
| Zdroj: | The Astrophysical Journal. 540:521-534 |
| ISSN: | 1538-4357 0004-637X |
| DOI: | 10.1086/309294 |
| Popis: | We report multifrequency radio observations of GRO J1655-40 obtained with the Australia Telescope Compact Array, the Molonglo Observatory Synthesis Telescope and the Hartebeesthoek Radio Astronomy Observatory at the time of the major hard X-ray and radio outbursts in 1994 August-September. The radio emission reached levels of the order of a few Jy and was found to be linearly polarized by up to 10%, indicating a synchrotron origin. The light curves are in good agreement with those measured with the VLA, but our closer time sampling has revealed two new short-lived events and significant deviations from a simple exponential decay. The polarization data show that the magnetic field is well ordered and aligned at right angles to the radio jets for most of the monitoring period. The time evolution of the polarization cannot be explained solely in terms of a simple synchrotron bubble model, and we invoke a hybrid `core-lobe' model with a core which contributes both synchrotron and free-free emission and `lobes' which are classical synchrotron emitters. Comment: 36 pages, 5 tables, 9 figures; accepted for publication in ApJ |
| Databáze: | OpenAIRE |
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