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RXTE Catalog

Thermonuclear (Type I) X-Ray Bursts Observed by the Rossi X-Ray Timing Explorer

Galloway, Duncan K.; Muno, Michael P.; Hartman, Jacob M.; Psaltis, Dimitrios; Chakrabarty, Deepto
ApJ S, 179, 360 (2008)
ADS | arXiv:0608259 | PDF (IOP)

We have assembled a sample of 1187 thermonuclear (type I) X-ray bursts from observations of 48 accreting neutron stars by the Rossi X-ray Timing Explorer, spanning more than 10 years. The sample contains examples of two of the three theoretical ignition regimes (confirmed via comparisons with numerical models) and likely examples of the third. We present a detailed analysis of the variation of the burst profiles, energetics, recurrence times, presence of photospheric radius expansion, and presence of burst oscillations, as a function of accretion rate. We estimated the distance for 35 sources exhibiting radius-expansion bursts, and found that the peak flux of such bursts varies typically by 13%. We classified sources into two main groups based on the burst properties: (1) both long and short bursts (indicating mixed H/He accretion), and (2) consistently short bursts (primarily He accretion), and we calculated the mean burst rate as a function of accretion rate for the two groups. The decrease in burst rate observed at >0.06Edd (>~2×1037 ergs s-1) is associated with a transition in the persistent spectral state and (as has been suggested previously) may be related to the increasing role of steady He burning. We found many examples of bursts with recurrence times <30 minutes, including burst triplets and even quadruplets. We describe the oscillation amplitudes for 13 of the 16 burst oscillation sources, as well as the stages and properties of the bursts in which the oscillations are detected. The burst properties are correlated with the burst oscillation frequency; sources spinning at <400 Hz generally have consistently short bursts, while the more rapidly spinning systems have both long and short bursts. This correlation suggests either that shear-mediated mixing dominates the burst properties, or alternatively that the nature of the mass donor (and hence the evolutionary history) has an influence on the long-term spin evolution.



If you notice an error please notify

  • The burst start times listed in the table are derived from MET values listed in the "packet" data provided by the instrument time at MIT. In the conversion from MET to UTC the TimeZero value of 3.378431 s was omitted. Furthermore, leap seconds were not correctly taken into account. Because these two corrections are in the opposite direction over the mission duration, the error is at most a few seconds. See the XTE Time Tutorial for more details. thanks to Anya Bilous and others for pointing out the error
  • Fig. 3 lists the date for the burst of 1999 July 30; the year should read 1997
  • Equation 6 omits a factor of the redshift; the correct prefactor (for a redshift of 1.31) is closer to 58. The full expression (requiring a conversion $ 1 \mathrm{erg g}^{-1} = 1.044\times10^{-18} \mathrm{MeV nucleon}^{-1} $) should be

$ \alpha=58\left(\frac{M}{1.4 M_\odot}\right)\left(\frac{R}{10 \mathrm{ km}}\right)^{-1} \left(\frac{Q_\mathrm{nuc}}{4.4\,\mathrm{ MeV nucleon}^{-1}}\right)^{-1}\left(\frac{1+z}{1.31}\right) $

  • In the source table, 4U 1916-053 is listed as type D, but should be DO (i.e. oscillation source) although see Watts et al. (2008)
  • In the section on EXO 0748-676, the first line should read "This transient ... was discovered during EXOSAT observations in 1985 (Parmar et al. 1986), "
  • The peak flux listed for XMMU J174716.1-281048 in Table 11 is in error; the revised bolometric peak flux is $ 5\times10^{-8} $ erg cm-2 s-1, with uncertainty <20% (Del Santo 2007, ATel #1207). This is substantially lower than the quoted 1-30 keV peak flux courtesy J. in 't Zand

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