NuSTAR observation of GRO J1744-28 at low mass accretion rate

OK thanks the ESAC Trainee Program (https://www.cosmos.esa.int/web/esac-trainees) which initiated this analysis, and the ERASMUS+ fellowship program for their financial support. RB acknowledges funding by Deutsches Zentrum fur Luft- und Raumfahrt under contract 50 OR 1606. MTW is supported by the NuSTAR Guest Investigator Program. This research has made use of ISIS functions (ISISscripts) provided by ECAP/Remeis observatory and MIT (http://www.sternwarte.uni-erlangen.de/isis/). This research has made use of the NuSTAR Data Analysis Software (NuSTARDAS) jointly developed by the ASI Science Data Center (ASDC, Italy) and the California Institute of Technology (USA).