SIMBAD references

We report the ASCA results of the bursting X-ray pulsar GRO J1744-28, which was observed in 1996 February and 1997 March. The source flux in the 2-10 keV band was 2.0x10^–8 ergs.s^–1.cm² in 1996 and 5.0x10^–9 ergs.s^–1.cm² in 1997. We detected 12 and 17 type II bursts during the two observations, with mean bursting intervals of about 27 min and 37 min. Each burst is followed by an intensity dip with the depleted flux depending on the burst fluence. The energy spectra are approximated by an absorbed power law with additional structure around 6-7 keV. The constant absorption column, (5-6)x10²² cm^–2, independent of the observation dates and emission phases (persistent, burst, and dip) is interpreted as an interstellar absorption. The source may be actually located near the Galactic center, at a distance of 8.5 kpc. The structure in the energy spectrum at 6-7 keV is most probably due to iron and may be reproduced by a disk line model with additional broadening mechanism.