TY - JOUR
T1 - Postburst quasi-periodic oscillations from GRO J1744-28 and from the rapid burster
AU - Kommers, Jefferson M.
AU - Fox, Derek W.
AU - Lewin, Walter H.G.
AU - Rutledge, Robert E.
AU - Van Paradijs, Jan
AU - Kouveliotou, Chryssa
N1 - Funding Information:
J. M. K. and D. W. F. acknowledge support from National Science Foundation Graduate Research Fellowships during the preliminary phase of this research. J. M. K. acknowledges subsequent support from a NASA Graduate Student Researchers Program Fellowship NGT8-52816. R. R. was supported by the NASA Graduate Student Researchers Program under grant NGT-51368. W. H. G. L. acknowledges support from NASA under grant NAG5-2046. J. v. P. acknowledges support from NASA under grant NAG5-2755. C. K. acknowledges support from NASA under grant NAG5-2560. We thank Dr. Ed Morgan for helpful discussions and assistance with the RXTE data archive at MIT.
PY - 1997
Y1 - 1997
N2 - The repetitive X-ray bursts from the accretion-powered pulsar GRO J1744-28 show similarities to the type II X-ray bursts from the Rapid Burster. Several authors (notably, Lewin et al.) have suggested that the bursts from GRO J1744-28 are type II bursts (which arise from the sudden release of gravitational potential energy). In this paper, we present another similarity between these sources. Rossi X-ray Timing Explorer observations of GRO J1744-28 show that at least 10 out of 94 bursts are followed by quasi-periodic oscillations (QPOs) with frequencies of ∼0.4 Hz. The period of the oscillations decreases over their ∼30-80 s lifetime, and they occur during a spectrally hard "shoulder" (or "plateau") that follows the burst. In one case, the QPOs show a modulation envelope that resembles simple beating between two narrow-band oscillations at ∼0.325 and ∼0.375 Hz. Using EXOSAT observations, Lubin et al. found QPOs with frequencies of 0.039-0.056 Hz following 10 out of 95 type II bursts from the Rapid Burster. As in GRO J1744-28, the period of these oscillations decreased over their ∼100 s lifetime, and they occurred only during spectrally hard "humps" in the persistent emission. Even though the QPO frequencies differ by a factor of ∼10, we believe that this is further evidence that a similar accretion disk instability is responsible for the type II bursts from these two sources.
AB - The repetitive X-ray bursts from the accretion-powered pulsar GRO J1744-28 show similarities to the type II X-ray bursts from the Rapid Burster. Several authors (notably, Lewin et al.) have suggested that the bursts from GRO J1744-28 are type II bursts (which arise from the sudden release of gravitational potential energy). In this paper, we present another similarity between these sources. Rossi X-ray Timing Explorer observations of GRO J1744-28 show that at least 10 out of 94 bursts are followed by quasi-periodic oscillations (QPOs) with frequencies of ∼0.4 Hz. The period of the oscillations decreases over their ∼30-80 s lifetime, and they occur during a spectrally hard "shoulder" (or "plateau") that follows the burst. In one case, the QPOs show a modulation envelope that resembles simple beating between two narrow-band oscillations at ∼0.325 and ∼0.375 Hz. Using EXOSAT observations, Lubin et al. found QPOs with frequencies of 0.039-0.056 Hz following 10 out of 95 type II bursts from the Rapid Burster. As in GRO J1744-28, the period of these oscillations decreased over their ∼100 s lifetime, and they occurred only during spectrally hard "humps" in the persistent emission. Even though the QPO frequencies differ by a factor of ∼10, we believe that this is further evidence that a similar accretion disk instability is responsible for the type II bursts from these two sources.
UR - http://www.scopus.com/inward/record.url?scp=21744441705&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=21744441705&partnerID=8YFLogxK
U2 - 10.1086/310669
DO - 10.1086/310669
M3 - Article
AN - SCOPUS:21744441705
SN - 0004-637X
VL - 482
SP - L53-L56
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1 PART II
ER -