First Images from HERO, a Hard X‐Ray Focusing Telescope

Abstract

We are developing a balloon-borne hard X-ray telescope that utilizes grazing-incidence optics. Termed HERO, for High-Energy Replicated Optics, the instrument will provide unprecedented sensitivity in the hard X-ray region and will achieve millicrab-level sensitivity in a typical 3 hr balloon-flight observation and 50 lcrab sensitivity on ultralong-duration flights. A recent proof-of-concept flight, featuring a small number of mirror shells, captured the first focused hard X-ray images of galactic X-ray sources. Full details of the pay-load, its expected future performance, and its recent measurements are provided.