A NuSTAR and Swift View of the Hard State of MAXI J1813-095
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Author
Jiang, Jiachen
Buisson, Douglas J. K.
Dauser, Thomas
Fabian, Andrew C.
Fürst, Felix
Gallo, Luigi C.
Harrison, Fiona A.
Parker, Michael L.
Steiner, James F.
Tomsick, John A.
Ubach, Santiago
Walton, Dominic J.
Attention
2299/26711
Abstract
We present an analysis of the NuSTAR and Swift spectra of the black hole candidate MAXI J1813−095 in a failed-transition outburst in 2018. The NuSTAR observations show evidence of reflected emission from the inner region of the accretion disc. By modelling the reflection component in the spectra, we find a disc inner radius of Rin < 7 rg. This result suggests that either a slightly truncated disc or a non-truncated disc forms at a few per cent of the Eddington limit in MAXI J1813−095. Our best-fitting reflection models indicate that the geometry of the innermost accretion remains consistent during the period of NuSTAR observations. The spectral variability of MAXI J1813−095 from multi-epoch observations is dominated by the variable photon index of the Comptonization emission.