  We report a broad-band analysis of a Galactic X-ray source, CXOGBS
J174517.0-321356 (J1745), with a 614-second periodicity. Chandra discovered the
source in the direction of the Galactic Bulge. Gong (2022) proposed J1745 was
either an intermediate polar (IP) with a mass of ~1 $M_{\odot}$, or an
ultra-compact X-ray binary (UCXB). By jointly fitting XMM-Newton and NuSTAR
spectra, we rule out a UCXB origin. We have developed a physically realistic
model that considers finite magnetosphere radius, X-ray absorption from the
pre-shock region, and reflection from the WD surface to determine the IP
properties, especially its WD mass. To assess systematic errors on WD mass
measurement, we consider a broad range of specific accretion rates ($\dot{m}$ =
0.6 - 44 g\cm$^2$\s) based on the uncertain source distance (d = 3-8 kpc) and
fractional accretion area (f = 0.001-0.025). Our model properly implements the
fitted accretion column height in the X-ray reflection model and accounts for
the underestimated mass accretion rate due to the (unobserved) soft X-ray
blackbody and cyclotron cooling emissions. We found that the lowest accretion
rate of $\dot{m}$ = 0.6 g\cm$^2$\s, which corresponds to the nearest source
distance and maximum f value, yield the WD mass of $(0.92\pm0.08) M_{\odot}$.
However, if the accretion rate is $\dot{m}$ > ~3 g\cm$^2$\s, the WD mass is
robustly measured to be $(0.81\pm0.06) M_{\odot}$, nearly independent of
$\dot{m}$. The derived WD mass range is consistent with the mean WD mass of
nearby IPs. Assuming spin equilibrium between the WD and accretion disk, we
constrained the WD magnetic field to B > ~7 MG, indicating that it could be a
highly magnetized IP. Our analysis presents the most comprehensive methodology
for constraining the WD mass and B-field of an IP by consolidating the effects
of cyclotron cooling, finite magnetospheric radius, and accretion column
height.
