G. Clark and F. Li, Massachusetts Institute of Technology, report that the SAS-3 Observatory has recorded a novalike increase in the x-ray flux from a source located in Norma within a 90-percent-confidence error circle of radius 0o.5 centered at R.A. = 16h09m, Decl. = -52o.4 (equinox 1950.0). The position determination is consistent with that of the previously reported persistent source MX1608-52 = 4U 1608-52, as well as with that of a burst source (cf. IAUC 2932, 2936). The flux began to increase about July 5.7 UT, reached a value of 4 x 10**-8 erg cm**-2 s**-1 (~ 1.1 times the Crab) in the energy range 1-10 keV on July 8.0 and declined slowly to 3 x 10**-8 erg cm**-2 s**-1 on July 9.0 and 2 x 10**-8 erg cm**-2 s**-1 on July 10.5. On July 7 the flux varied on a timescale of seconds. Optical observers are urged to search for an optical nova counterpart.
International Astronomical Union Circular
- Pub Date:
- July 1977