Speaker
Description
XRISM/Xtend Transient Search (XTS) detected an X-ray flare from a Chandra X-ray source CXOGNC J104457.51-595429.5, which was identified with a Gaia source, DR2 5350302509372303744 or Cl Collinder 228 113 (ATel #16652). From the SED and the distance of ∼1.3 kpc, we found that Cl Collinder 228 113 has the spectrum type of K7 giant. The X-ray spectrum of this source has a strong Fe-K line at the flare phase, and it requires a large abundance of 2 solar, when we fit it with a thermal plasma (APEC) model. The other derived parameters are plasma temperature of kT ~4 keV and Emission Measure of 1 x 10^54 cm^-3. The flux in the 0.4–10.0 keV band is 1 x 10^-12 ergs/cm^2/s and the corresponding X-ray luminosity is 3 x 10^32 ergs/s. The e-folding time of the decay phase is derived to be 1 x 10^4 sec from the light curve, and then the total released energy in the 0.4–10.0 keV band is 3.4 × 10^36 erg. These parameters are not inconsistent with the correlations of the Emission Measure vs. kT and X-ray luminosity vs. e-folding time, which are shown in Shibata and Yokoyama (1999 ApJ) and Tsuboi et al. (2016 PASJ).
