A. M. Wilson and G. F. Carpenter, Department of Space Research, University of Birmingham, communicate: "Further analysis of our observations of Cir X-1 (Wilson and Carpenter 1976, Nature 261, 295) gives the following revised position for this source: R.A. = 15h16m46s, Decl. = -56o59'20" (equinox 1950.0; 90-percent-confidence radius 55"). We note that the optical candidate proposed by Mayo et al. (IAUC 2957) lies 17" from our most probable position." L. J. Kaluzienski, S. S. Holt, M. Esfandiari, E. A. Boldt and P. J. Serlemitsos, Goddard Space Flight Center, report the detection of a flare in Aquila with the Ariel 5 all-sky monitor. The intensity at 3-6 keV was approximately 0.3 times that of the Crab on June 7 and <~ 0.2 times the Crab for at least one week prior to that date. The flux increased steadily between June 7 and 13 (being ~ 0.7 times the Crab on June 10 and 1.0 times on June 13) and remained at about the level of the Crab through June 16. While a new transient source can not be excluded at present, the data are entirely consistent with Aql X-1 (3U 1908+00) as the flare source candidate: the risetime and peak flux level are similar to those observed in the June 1975 flare of that source (cf. IAUC 2788).
International Astronomical Union Circular
- Pub Date:
- June 1976