Discovery of intense X-ray bursts from the globular cluster NGC 6624

Grindlay, J.; Gursky, H.; Schnopper, H.; Parsignault, D. R.; Heise, J.; Brinkman, A. C.; Schrijver, Carolus J.

doi:10.1086/182105

Cited by 254 publications

(193 citation statements)

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“…The small (~1 arcmin) Uhuru error box for 3U1820-30 has been further refined to be within ~40arcsec of the core of NGC 6624 by SAS-3 (Jernigan 1976). This source was the first identified globular cluster burster (Grindlay et al 1976a). The X-ray sources 3U1747-37 and 3U 2131+11 had larger positional uncertainties (~0.1° and ~1°) but included the clusters NGC 6441 and NGC7078 (Ml5) in their error boxes.…”

Section: IImentioning

confidence: 92%

“…Although the globular cluster X-ray luminosities may suggest similarities to the Sco X-1 or Cyg X-2 type sources, their high range of intensity variability and spectra do suggest similarities to the high luminosity GX sources. The time variations of NGC 6624 (at least) are also reminiscent of Cyg X-1, with long-term "high" and "low" (bursting) states (Grindlay et al 1976a; Clark e t a h 1976), ~ 10 mln flares (Canizares and Neighbours 1975) and ~ 1 sec bursts. No millisecond variability has yet been detected from 3U1820-30 (Grindlay 1976), however.…”

Section: IImentioning

confidence: 99%

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Globular Cluster X-Ray Sources

Grindlay

1977

Highlights astron.

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The discoveries of both steady and bursting X-ray sources in globular clusters have made them as interesting for high energy astrophysics and X-ray astronomy as they were for unlocking galactic structure in Shapley’ s day. Globular clusters are massive (˜ 105M⊙) spherical clusters of primarily low mass (⋞0.8 M⊙) evolved stars and may be the oldest systems in the Galaxy. Thus when several globular clusters were tentatively identified as containing X-ray sources (Giacconiet al. 1974), it was apparent that either dynamical or evolutionary processes must be occurring among the ancient stars in globular clusters to produce the relatively short-lived X-ray sources. The existence of these X-ray sources has prompted considerable discussion as to their origin, since they exist with ˜100 times the probability per unit mass in globular clusters as in the Galaxy as a whole (Katz 1975; Clark 1975). They may be yet another example of X-ray binaries (e. g., Clark 1975; Fabianet al. 1975) or be due to accretion onto a single collapsed object (black hole) at the center of the cluster (Bahcall and Ostrlker 1975; Silk and Arons 1975). At present both of these classes of models are possible and generally consistent with the data, though each has its particular difficulties. We shall review the observational data and then the models in an effort to point out the present balance of evidence for the binaryvs.black hole models as well as the most promising directions for future work. Given the possibly high incidence of X-ray bursters in globular clusters, our discussion will refer to both observations and recent models for bursters. While this review will primarily address the X-ray sources in globular clusters, it is obvious that their eventual understanding will contribute much to studies of globular clusters in general and will prompt future studies in particular areas.

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Section: IImentioning

confidence: 92%

Section: IImentioning

confidence: 99%

Globular Cluster X-Ray Sources

Grindlay

1977

Highlights astron.

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“…When ignition conditions are met at the bottom of the accreted shell, unstable reactions trigger a thermonuclear runaway that quickly burns the pile of fuel, generally a mix of hydrogen (H), helium (He), and heavier elements ("metals"). This cyclic phenomenon has been observed for four decades in what are known as thermonuclear (type I X-ray) bursts (Belian et al 1976;Grindlay et al 1976).…”

Section: The Rare and Most Energetic Thermonuclear Burstsmentioning

confidence: 97%

The Fermi–gbm Three-Year X-Ray Burst Catalog

Jenke

Linares

Connaughton

et al. 2016

ApJ

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The Fermi Gamma-ray Burst Monitor (GBM) is an all-sky gamma-ray monitor well known in the gamma-ray burst (GRB) community. Although GBM excels in detecting the hard, bright extragalactic GRBs, its sensitivity above 8 keV and its all-sky view make it an excellent instrument for the detection of rare, short-lived Galactic transients. In 2010 March, we initiated a systematic search for transients using GBM data. We conclude this phase of the search by presenting a three-year catalog of 1084 X-ray bursts. Using spectral analysis, location, and spatial distributions we classified the 1084 events into 752 thermonuclear X-ray bursts, 267 transient events from accretion flares and X-ray pulses, and 65 untriggered gamma-ray bursts. All thermonuclear bursts have peak blackbody temperatures broadly consistent with photospheric radius expansion (PRE) bursts. We find an average rate of 1.4 PRE bursts per day, integrated over all Galactic bursters within about 10 kpc. These include 33 and 10 bursts from the ultra-compact X-ray binaries 4U0614+09 and 2S0918-549, respectively. We discuss these recurrence times and estimate the total mass ejected by PRE bursts in our Galaxy.

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“…The class of explosions called X-ray bursts is thought to result from collecting hydrogen-rich matter and then rapidly burning it on the surface of the neutron star [22,23]. These outbursts rise to a maximum luminosity of approximately 10 38 ergs s −1 on time scales of seconds and decay on time scales of seconds to hundreds of seconds, emitting a total of approximately 10 39 ergs.…”

Section: (B) Neutron Star and Black Hole Binary Transientsmentioning

confidence: 99%

Astrophysical explosions: from solar flares to cosmic gamma-ray bursts

Wheeler

2012

Phil. Trans. R. Soc. A.

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Astrophysical explosions result from the release of magnetic, gravitational or thermonuclear energy on dynamical time scales, typically the sound-crossing time for the system. These explosions include solar and stellar flares, eruptive phenomena in accretion discs, thermonuclear combustion on the surfaces of white dwarfs and neutron stars, violent magnetic reconnection in neutron stars, thermonuclear and gravitational collapse supernovae and cosmic gamma-ray bursts, each representing a different type and amount of energy release. This paper summarizes the properties of these explosions and describes new research on thermonuclear explosions and explosions in extended circumstellar media. Parallels are drawn between studies of terrestrial and astrophysical explosions, especially the physics of the transition from deflagration-to-detonation.

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Discovery of intense X-ray bursts from the globular cluster NGC 6624

Cited by 254 publications

References 0 publications

Globular Cluster X-Ray Sources

Globular Cluster X-Ray Sources

The Fermi–gbm Three-Year X-Ray Burst Catalog

Astrophysical explosions: from solar flares to cosmic gamma-ray bursts

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