The relativistically-broadened reflection spectrum, observed in both AGN and X-ray binaries, has proven to be a powerful probe of the properties of black holes and the environments in which they reside. Being emitted from the inner-most regions of the accretion disk, this X-ray spectral component carries with it information not only about the plasma that resides in these extreme conditions, but also the black hole spin, a marker of the formation and accretion history of these objects. The models currently used to interpret the reflection spectrum are often simplistic, however, approximating the disk as an infinitely thin, optically thick plane of material orbiting in circular Keplerian orbits around the central object. Using a new relativistic ray tracing suite (Fenrir) that allows for more complex disk approximations, we examine the effects that disk thickness may have on the reflection spectrum. Assuming a lamp post corona, we find that finite disk thickness can have a variety of effects on the reflection spectrum, including a truncation of the blue wing (from self-shadowing of the accretion disk) and an enhancement of the red wing (from the irradiation of the central 'eye wall' of the inner disk. We deduce the systematic errors on black hole spin and height that may result from neglecting these effects.

keV) 21,760 cm2 Energy Resolution 85 -175 eV FWHM Time Resolution 100 ns Collimator 4 arcmin FWHM Background Rate 2.2 c/s Count Rate on Crab (0.2-10 keV) 148,000 Large Area Detector (LAD) Energy Range 2-30 keV Effective Area (cm^2 @ 10 keV) 51,000 cm2 Energy Resolution 200 -300 eV FWHM Time Resolution 10 µs Collimator 1° FWHM Count Rate on Crab (2-30 keV) 156,000 Background Rate 822 c/s (5 mcrab)

We use particle data from the Illustris simulation, combined with individual kinematic constraints on the mass of the Milky Way (MW) at specific distances from the Galactic Centre, to infer the radial distribution of the MW's dark matter halo mass. Our method allows us to convert any constraint on the mass of the MW within a fixed distance to a full circular velocity profile to the MW's virial radius. As primary examples, we take two recent (and discrepant) measurements of the total mass within 50 kpc of the Galaxy and find that they imply very different mass profiles and stellar masses for the Galaxy. The dark-matter-only version of the Illustris simulation enables us to compute the effects of galaxy formation on such constraints on a halo-by-halo basis; on small scales, galaxy formation enhances the density relative to dark-matter-only runs, while the total mass density is approximately 20% lower at large Galactocentric distances. We are also able to quantify how current and future constraints on the mass of the MW within specific radii will be reflected in uncertainties on its virial mass: even a measurement of M (< 50 kpc) with essentially perfect precision still results in a 20% uncertainty on the virial mass of the Galaxy, while a future measurement of M (< 100 kpc) with 10% errors would result in the same level of uncertainty. We expect that our technique will become even more useful as (1) better kinematic constraints become available at larger distances and (2) cosmological simulations provide even more faithful representations of the observable Universe.