The Infall of the Virgo Elliptical Galaxy M60 toward M87 and the Gaseous
  Structures Produced by Kelvin-Helmholtz Instabilities
  We present Chandra observations of hot gas structures, characteristic of gas
stripping during infall, in the Virgo cluster elliptical galaxy M60 (NGC4649)
located $1$ Mpc east of M87. $0.5-2$ keV Chandra X-ray images show a sharp
leading edge in the surface brightness $12.4 \pm 0.1$ kpc north and west of the
galaxy center in the direction of M87 characteristic of a merger cold front due
to M60's motion through the Virgo ICM. We measured a temperature of $1.00 \pm
0.02$ keV for abundance $0.5 Z_\odot$ inside the edge and
$1.37^{+0.35}_{-0.19}$ keV for abundance $0.1 Z_\odot$ in the Virgo ICM free
stream region. We find that the observed jump in surface brightness yields a
density ratio of $6.44^{+1.04}_{-0.67}$ between gas inside the edge and in the
cluster free stream region. If the edge is a cold front due solely to the
infall of M60 in the direction of M87, we find a pressure ratio of
$4.7^{+1.7}_{-1.4}$ and Mach number $1.7 \pm 0.3$. For 1.37 keV Virgo gas we
find a total infall velocity for M60 of $1030 \pm 180$ kms$^{-1}$. We calculate
the motion in the plane of the sky to be $1012^{+183}_{-192}$ km$^{-1}$
implying an inclination angle $\xi = 11 \pm 3$ degrees. Surface brightness
profiles show the presence of a faint diffuse gaseous tail. We identify
filamentary, gaseous wing structures caused by the galaxy's motion through the
ICM. The structure and dimensions of these wings are consistent with
simulations of Kelvin-Helmholtz instabilities as expected if the gas stripping
is close to inviscid.
