Self-Consistent Disk-Reflection Analysis of theX-ray Binary Black Hole Candidate MAXIJ1813-095 withNICER, Swift, Chandra, andNuSTAR

We present an analysis of NICER, Swift, Chandra and NuSTAR spectra of the black hole candidate MAXI J1813-095 near during its hard-state-only outburst in 2018. The observations show evidence of Fe K emission at ~6.5 keV originating from the inner accretion disk. We apply self-consistent Comptonized-disk and reflection models to the spectra in order to place constraints on the inner radius (which establishes a lower-limit on the spin) and on the reflection model. Our modeling finds a consistent innermost disk radius between all the observations. The multi-epoch study spans a month near its peak during which the flux is stable at roughly ~5×10^-10erg cm^-2s^-1(1-10 keV).