XTE J1946+274 = GRO J1944+26
Abstract
D. A. Smith, Massachusetts Institute of Technology (MIT); and T. Takeshima, Goddard Space Flight Center (GSFC), NASA, on behalf of the RXTE/ASM and PCA teams at MIT and GSFC, communicate: "The ASM on RXTE has detected emission from a location that overlaps the previous localization of the 1976 Ariel V transient 3A 1942+274 (Warwick et al. 1981, MNRAS 197, 865; galactic latitude +1.7 deg). The corners of the ASM 6' x 26' error region are at R.A. = 19h47m.1, Decl. = +27o16'; 19h46m.2, +27o25'; 19h45m.5, +27o25'; 19h46m.2, +27o18' (equinox 2000.0; 90-percent-confidence total error). The source first came to our attention at about 90 mCrab (2-12 keV) on Sept. 15.91 UT, with a very hard spectrum. A retroactive search reveals that the 1-day average intensity has been rising from 13 mCrab on Sept. 5 to 60 mCrab on Sept. 15. The RXTE/PCA observed this location on Sept. 16.02 and recorded an intensity of about 110 mCrab (2-60 keV) with a very strong 15.83-s (+/- 0.02 s) pulsation. The pulse profile is double-peaked, with a pulse fraction of about 29 percent. There is, to our knowledge, no previous report of pulsations from 3A 1942+274. If this is a reoccurrence of the Ariel source, the 8' x 52' Ariel position restricts the location to the westernmost 5' of the ASM region (see http://xte.mit.edu/~dasmith/x1946_map.gif). Further PCA observations are in progress. Observations at other wavelengths are encouraged."
- Publication:
-
International Astronomical Union Circular
- Pub Date:
- September 1998
- Bibcode:
- 1998IAUC.7014....1S