Evolution of the 1984 outburst of the transient X-ray source 4U 1630 - 47

Journal Article · Thu May 01 04:00:00 EDT 1986 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/164204· OSTI ID:5199476

Parmar, A N; Stella, L; White, N E

The results of a series of EXOSAT observations of the X-ray transient 4U 1630 - 47 during an outburst in 1984 are presented. The source decayed over an interval of about 100 days from a maximum 1-50 keV luminosity of about 2.8 x 10 to the 38th to about 4 x 10 to the 36th erg/s (for an assumed distance of 10 kpc). The 1-50 keV spectrum was best represented by a soft Wien-like spectrum with a temperature about 1 keV and a high-energy power-law tail. The relative contribution of the soft component to that of the high-energy power law decreased by atleast a factor of about 2 as the overall luminosity decreased. When the source was at its maximum observed luminosity, short time scale 7 percent intensity variations (1-7 keV) were seen with a characteristic time scale of about 20 s. The shortest time scale variability detected was about 50 ms. A 10-arcsec position obtained using an imaging telescope excludes a previously suggested optical counterpart. The spectral properties of 4U 1630 - 47 are reminiscent of those of the black hole candidate Cyg X-1 when it evolves from a high to a low state. 28 references.

• Research Organization: EXOSAT Observatory, Darmstadt, West Germany
• OSTI ID: 5199476
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 304; ISSN ASJOA
• Country of Publication: United States
• Language: English

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