Brandt's research focuses on observational studies of supermassive black holes (SMBHs) and cosmological X-ray surveys. Specific
objects investigated include actively accreting SMBHs (i.e., active galactic nuclei: AGNs), starburst galaxies, and
normal galaxies. His work utilizes data from facilities at the forefront of astrophysical discovery, including the
Chandra X-ray Observatory, XMM-Newton, NuSTAR, and the Sloan Digital Sky Survey. He is also involved with
upcoming projects including the Large Synoptic Survey Telescope, the Advanced Telescope for High Energy Astrophysics (ATHENA),
and new X-ray missions. In his cosmological X-ray surveys work, Brandt has been a leader in obtaining the most-sensitive X-ray
surveys to date, including the Chandra Deep Field-North and the Chandra Deep Field-South. These have been used to
explore the demography, physics, and ecology of typical growing SMBHs over most of cosmic history. They have also
allowed the study of X-ray source populations in starburst and normal galaxies out to cosmological distances.
In his general AGN studies, he has investigated AGN winds, the X-ray properties of the first quasars, and extreme AGN populations
(e.g., Narrow-Line Seyfert 1 galaxies and weak-line quasars). He has also worked on investigations of the cosmic microwave background radiation and the effects of neutron-star and black-hole natal kicks. Brandt is an author of more than 500 research papers on these subjects.
Brandt leads a small research group including postdoctoral researchers, graduate students, and undergraduate students.
Many of them, after developing their skills via their research projects, have gone on to win professorial and permanent staff
positions as well as distinguished fellowships and scholarships, becoming new leaders around the world in astrophysics.
Brandt also regularly teaches courses on high-energy astrophysics, bremsstrahlung, black holes, and active galaxies.