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The data are limited to those taken with 1650-V counters since 2009 October 31 to 2 days ago excepting for the GSC_3. Please read the notes in “About this page” before you start the analysis.
We analyzed the MAXI/GSC light curve of an X-ray burst from EXO
1745-248 in Terzan 5 reported in Atel #3714, #3718, #3720 and found
that the initial peak at MJD 55858.53 decayed exponential with an
e-folding time of 10 hour.
If the emission is a blackbody radiation, the temperature can be estimated from the hardness of two energy bands.
MJD 4-10/2-4 keV kT [keV] 10-20/4-10 keV kT [keV]
55858.53 2.9 2.9 +- 0.8 0.32 2.4 +- 0.6
55858.59 1.5 1.7 +- 0.4 0.19 2.0 +- 0.8
55858.78 1.05 1.4 +- 0.4 0.50 2.8 +- 1.0
55858.84 1.24 1.58 +- 0.5 0.37 1.85 +- 0.8
55858.91 1.06 1.43 +- 0.5 0.19 1.83 +- 1.5
55858.97 1.03 1.40 +- 0.5 0.06 1.80 +- 3.9
(Errors are 1-sigma.)
The values derived from 4-10/2-4 keV and 10-20/4-10 keV
are consistent with each other. It showed a softening from 2.9 keV in the beginning to 1.5 keV in the end.
The fluence is 2.4 x 1042 erg in 2-10 keV assuming 8.7 kpc distance (Cohn et al. ApJ 571 818 (2002)). Using H burning energy of 6 x 1018 erg/g, the mass of H is 4.0 x 1023 g. Using the average flux of 10 mCrab (1.7 x 1036 erg/s, 9.0 x 1015 g/s), the reputation time is calculated to be 510 yr. (<- It was a mistale. Correctly 510 days. If we use C-burning energy it becomes 5100 days = 14 yrs. by TM 2011.11.16)
The sphere radius of the blackbody is 6.3 km with using 2 keV and 6.8 x 1037 erg/s at the peak.
These results (e-folding time, temperature, softening, fluence, and radius) are typical as a super-burst from low-mass X-ray binaries.
Atel #3729
Archived light-curve data is available at