| タイトル | Multiwavelength observations of Hercules X-1/HZ Herculis |
| 著者（英） | Agerer, F.; Primini, F. A.; Charles, P. A.; Kahabka, P.; Cheng, F. H.; Dennerl, K.; Mihara, T.; Marshall, H.; Ladous, C.; Vrtilek, S. D. |
| 著者所属（英） | NASA Goddard Space Flight Center; NASA Headquarters |
| 発行日 | 1994-11-20 |
| 言語 | eng |
| 内容記述 | We present first results from a multiwavelength campaign to observe the binary pulsar system Her X-1/ HZ Her. The campaign spanned 4 days during 1993 August: observations were taken with five satellites (IUE, EUVE, ROSAT, ASCA, and CGRO/BATSE) and several ground-based facilities. A substantial, unexpected drop in flux at X-ray energies, with no change in absorbing column density, was observed. The pulse period has increased from the previous measurement, contrary to the usual spin-up, and no pulsed emission is detected above 0.9 keV in the low state. The optical and UV fluxes continued to show 1.7 day modulation attributed to X-ray heating of the companion star. However, the significant reduction in UV flux observed around eclipse implies an absence of the normally observed excess attributed to X-ray heating of the disk. We conclude that we have observed an anomalous low state, seen only once before (Parmar et al. 1985), in which the X-ray flux is not redistributed but obscured. We suggest explanations for the behavior of the flux at different wavelengths. |
| NASA分類 | ASTROPHYSICS |
| レポートNO | 95A68450 |
| 権利 | Copyright |
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