Discovery and Orbital Determination of the Transient X‐Ray Pulsar GRO J1750−27

D. M. Scott, M. H. Finger, R. B. Wilson, D. T. Koh, T. A. Prince, B. A. Vaughan, D. Chakrabarty
1997 Astrophysical Journal  
We report on the discovery and hard X-ray (20È70 keV) observations of the 4.45 s period transient X-ray pulsar GRO J1750[27 with the BATSE all-sky monitor on board CGRO. A relatively faint outburst (\30 mcrab peak) lasting at least 60 days was observed during which the spin-up rate peaked at 38 pHz s~1 and was correlated with the pulsed intensity. An orbit with a period of 29.8 days was found. The large spin-up rate, spin period, and orbital period together suggest that accretion is occurring
more » ... tion is occurring from a disk and that the outburst is a "" giant ÏÏ outburst typical of a Be/X-ray transient system. No optical counterpart has yet been reported.
doi:10.1086/304740 fatcat:djymdljs6fazdaglnm3fulq3oe