Embedded Spiral Patterns in the Cool Core of the Massive Cluster of
  Galaxies Abell 1835
  We present the properties of intracluster medium (ICM) in the cool core of
the massive cluster of galaxies Abell 1835 obtained with the data by $ Chandra$
$X$-$ray$ $Observatory$. We find distinctive spiral patterns with the radius of
70 kpc (or 18 arcsec) as a whole in the residual image of X-ray surface
brightness after the 2-dimensional ellipse model of surface brightness is
subtracted. The size is smaller by a factor of 2 -- 4 than that of other
clusters known to have a similar pattern. The spiral patterns consist of two
arms. One of them appears as positive, and the other does as negative excesses
in the residual image. Their X-ray spectra show that the ICM temperatures in
the positive- and negative-excess regions are $5.09^{+0.12}_{-0.13}$ keV and
$6.52^{+0.18}_{-0.15}$ keV, respectively. In contrast, no significant
difference is found in the abundance or pressure, the latter of which suggests
that the ICM in the two regions of the spiral patterns is in pressure
equilibrium or close. The spatially-resolved X-ray spectroscopy of the central
region ($r<40$ arcsec) divided into 92 sub-regions indicates that Abell 1835 is
a typical cool core cluster. We also find that the spiral patterns extend from
the cool core out to the hotter surrounding ICM. The residual image reveals
some lumpy sub-structure in the cool core. The line-of-sight component of the
disturbance velocity responsible for the sub-structures is estimated to be
lower than 600 km/s. Abell 1835 may be now experiencing an off-axis minor
merger.
