X-ray observations of circumgalactic coronae provide a valuable means by which to test galaxy formation theories .
Two primary mechanisms are thought to be responsible for the establishment of such coronae : accretion of intergalactic gas and/or galactic feedback .
In this paper , we first compare our Chandra sample of galactic coronae of 53 nearby highly-inclined disc galaxies to an analytical model considering only the accretion of intergalactic gas .
We confirm the existing conclusion that this pure accretion model substantially over-predicts the coronal emission .
We then select 30 field galaxies from our original sample , and correct their coronal luminosities to uniformly compare them to deep X-ray measurements of several massive disc galaxies from the literature , as well as to a comparable sample of simulated galaxies drawn from the Galaxies-Intergalactic Medium Interaction Calculation ( GIMIC ) .
These simulations explicitly model both accretion and supernovae feedback and yield galaxies that exhibit X-ray properties in broad agreement with our observational sample .
However , notable and potentially instructive discrepancies exist between the slope and scatter of the L _ { X } - M _ { 200 } and L _ { X } - { SFR } relations , highlighting some known shortcomings of GIMIC , for example , the absence of AGN feedback , and possibly the adoption of constant stellar feedback parameters .
The simulated galaxies exhibit a tight correlation ( with little scatter ) between coronal luminosity and halo mass .
Having inferred M _ { 200 } for our observational sample via the Tully-Fisher relation , we find a weaker and more scattered correlation .
In the simulated and observed samples alike , massive non-starburst galaxies above a typical transition mass of M _ { * } \sim 2 \times 10 ^ { 11 } ~ { } M _ { \odot } or M _ { 200 } \sim 10 ^ { 13 } ~ { } M _ { \odot } tend to have higher L _ { X } / M _ { * } and L _ { X } / M _ { 200 } than low-mass counterparts , indicating that the accretion of intergalactic gas plays an increasingly important role in establishing the observable hot circumgalactic medium with increasing galaxy mass .