A New Broadband Spectral State in the Ultraluminous X-ray Source Holmberg IX X-1

D. J. Walton, M. Bachetti, P. Kosec +12

We present a series of five new broadband X-ray observations of the ultraluminous X-ray source Holmberg IX X-1, performed by $XMM$-$Newton$ and $NuSTAR$ in coordination. The first…