  We apply halo abundance matching to obtain galaxy virial masses, M_h, and
radii, Rvir, for the 183 isolated galaxies in the "MgII Absorber-Galaxy
Catalog" (MAGIICAT, Nielsen et al.). All galaxies have spectroscopic redshifts
(0.1 < z < 1.1) and their circumgalactic medium (CGM) is probed in MgII
absorption within projected galactocentric distances D < 200 kpc. We examine
the behavior of equivalent width, W(2796), and covering fraction, f_c, as a
function of D, D/Rvir, and M_h. We find: [1] systematic segregation of M_h on
the W(2796)-D plane (4.0 sigma); high-mass halos are found at higher D with
larger W(2796) compared to lower mass halos. On the W(2796)-D/Rvir plane, mass
segregation vanishes and we find W(2796) ~ (D/Rvir)^-2 (8.9 sigma); [2] higher
mass halos have larger f_c at a given D, whereas f_c is independent of M_h at
all D/Rvir; [3] f_c is constant with M_h over the range 10.7 < log(M_h/Msun) <
13.8 within a given D or D/Rvir. The combined results suggest that the MgII
absorbing CGM is self-similar with halo mass, even above log(M_h/Msun)~12,
where cold mode accretion is theoretically predicted to be quenched. If theory
is correct, either outflows or sub-halos must contribute to absorption in
high-mass halos such that low- and high-mass halos are observationally
indistinguishable using MgII absorption strength once impact parameter is
scaled by halo mass. Alternatively, the data may indicate that predictions of a
universal shut down of cold-mode accretion in high-mass halos may require
revision.
