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tokens: events for both the pn and MOS. The events detected in the two MOS cameras were combined into a single data set, and we used averaged response files. Since with the ML analysis it is possible to derive an accurate estimate of the background at the source position, it was not necessary to remove time intervals of high background. We applied the ML in a circular region positioned to avoid the gaps between the CCD chips (radius of 60, center at R.A. = 11 h 54 m 232, decl. = −62°49′47′′). For the spectral extraction we fixed the source position at the coordinates found by the ML in the pn+MOS image in the 0.4–2 keV range (R.A. = 11 h 54 m 204, decl. = −62°50′044). This position is consistent with that found with the SAS pipeline. In the energy range 0.4–2 keV the source was detected with 113 ± 21 counts (pn) and 66 ± 15 counts (MOS), which correspond to a total count rate of (3.4 ± 0.5) × 10 −3 count s −1 . The energy bins for the spectral analysis were chosen from the requirement to have a signal-to-noise ratio greater than 2.5 σ in each spectral channel. This resulted in four energy bins for the pn and three for the MOS. Below 0.4 keV and above 2 keV, the source detection was below our significance threshold; therefore we derived upper limits on the source counts in these energy bins. 3. Possible Optical Counterparts In the Gaia database there are no stars closer than 4′′ to the corrected X-ray position; see Figure 1 . The closest object, at 406, is Gaia DR 2 5334588220496359424 which has g = 17.48. A slightly brighter star, Gaia DR2 5334588151811060992 with g = 14.15, is located at 429. It has B = 16.4, I = 13.11, J = 11.937, and K = 10.951, while the fainter source has B = 19.6, I = 16.08, J = 14.07, and K = 12.86 (Epchtein et al. 1999 ). Based on the color differences I − J and J − K , we identify the brighter star as a main sequence star of spectral type K5 and the fainter one as an M5 star. We fitted the spectra of our X-ray source with thermal plasma models ( apec by Smith et al. 2001 ; mekal by Mewe et al. 1985 ), as expected in the case of coronal emission from normal stars. Acceptable fits could be obtained with temperatures in the range kT = 0.23–0.26 keV, absorption N H ∼ 10 22 cm −2 , and flux ∼3 × 10 −15 erg cm −2 s −1 . The resulting X-ray-to-optical flux ratios (Agüeros et al. 2009 ) were −3.34 and −2.6 for the K and M star, respectively. These values are compatible with X-ray emission from late-type stars and therefore we cannot exclude these objects as potential counterparts of the X-ray source based on spectral and/or flux arguments. However, we note that both stars are outside the 3 σ confidence level error circle of the X-ray source and therefore we consider that PSR J1154–6250 is much more likely responsible for the detected X-ray emission. 4. Results The results of the spectral analysis obtained with the two methods are summarized in Table 3 . The absorption column density was poorly constrained due to the small