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Energy Spectrum of a Nova-like X-ray Source


A NEW X-ray source was born near or in the Centaurus constellation during July 6–9, 1969 (see refs. 1 and 2). In a few days the source reached a maximum intensity that was approximately twice that of Sco X-1. The intensity remained nearly constant for about two months after which it decreased to approximately a half of its maximum. The source became dim gradually from early September and unobservable at the end of September. The hardness of the spectrum represented by the ratio of counts over 6–12 keV to counts over 3–6 keV had kept constant after the source passed the first phase of its development. We have reported3 the measurement of the source in the energy range 2–20 keV performed with well calibrated proportional counters on board a sounding rocket, Kappa-9M, launched on August 7, 1969, from KSC (Kagoshima Space Center, 131° 04′ 45″ E, 31° 13′ 00″ N).

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  1. 1

    Conner, J. P., Evans, W. D., and Belian, R. D., Ap. J., 157, L157 (1969).

  2. 2

    Evans, W. D., Belian, R. D., and Conner, J. P., Ap. J., 159, L57 (1970).

  3. 3

    Kitamura, T., Matsuoka, M., Miyamoto, S., Nakagawa, M., Oda, M., Ogawara, Y., and Takagishi, K., Nature, 224, 784 (1969).

  4. 4

    Bell, K. L., and Kingston, A. E., Mon. Not. Roy. Astron. Soc., 136, 241 (1967).

  5. 5

    Chodil, G., Mark, H., Rodrigues, R., Seward, F., Swift, C. D., Hiltner, W. A., Wellerstein, G., and Mannery, J., Phys. Rev. Lett., 19, 681 (1967).

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