NuSTAR and INTEGRAL observations of a low/hard state of 1E1740.7-2942

Understand

The microquasar 1E1740.7-2942, also known as the "Great Annihilator", was observed by NuSTAR in the Summer of 2012.

• We have analyzed in detail two observations taken ~2 weeks apart, for which we measure hard and smooth spectra typical of the low/hard state.
• A few weeks later the source flux declined significantly.
• Nearly simultaneous coverage by INTEGRAL is available from its Galactic Center monitoring campaign lasting ~2.5 months.