Galactic emission – this region contains no other bright objects. All the XIS data were taken with both 3$\times$3 and 5$\times$5 pixel mode. The observation log is summarized in Table 1.

[cccc]{} Target & NGC 4636 & $^1$NGC 4636-NORTH & $^2$NGC 4636-GALACTIC\
z & 0.00313 & - & -\
position (Ra, Dec) in J2000 & 190.7250, 2.7520 & 190.6828, 3.0503 & 192.5138, 5.4608\
exposure time (ks) & 70.3 & 51.1 & 34.9\
date (y-m-d h:m) & 05-12-06 06:38 & 07-12-07 05:01 & 07-06-17 20:11\
\
\

We analyzed the public rev 1.2 data and screened them with cut-off rigidity (COR) $>$ 8 GV, target elevation angle above the earth rim (ELV) $>$ 5$^{\circ}$, and elevation angle above the day earth rim (DYE\_ELV) $>$ 20$^{\circ}$. For the 2005 observation, we extracted spectra of six annular regions centered on the X-ray peak (Figure 1(a)). For the north offset observation, we analyzed the spectrum of a 8’-radius aperture centered on a position at 20’ away from the galaxy center (Figure 1(b)). In extracting the above spectra, we excluded the region which is contaminated by the Fe calibration source. We used xisrmfgen version 2006-11-26 and xissimarfgen version 2006-10-26 to make response matrix files (RMF) 