MIT Kavli Institute Directory

Jack Steiner

Einstein Postdoctoral Fellow Postdoctoral Scholar

James (“Jack”) Steiner graduated with his PhD in Astronomy from Harvard University in 2012, and earned bachelors degrees in Applied Mathematics and Astrophysics from Ohio University.  After completing his PhD, Jack worked as a postdoctoral fellow at the IoA in Cambridge, and as a Hubble Fellow at SAO before taking up his current position as an Einstein Fellow at MIT.

Research interests: 

Jack’s research involves observations of black hole systems, especially stellar-mass black holes and black holes in ultraluminous X-ray sources (ULXs).  Black holes are of fundamental importance to physics and astrophysics alike. To understand their behavior and to ultimately test general relativity in the strong field regime it is essential to establish reliable methods of measuring their sole two attributes: mass and spin (as per the famous no-hair theorem).  Determining black hole spin is likewise a key objective for current and forthcoming X-ray missions including NuSTAR, Astro-H, ASTROSAT, and Athena, and is closely aligned with numerous other missions, notably RXTE, and NICER.   While Jack's research is focused on measuring spin and probing the relationship between spin and black hole jets,  this work dovetails more broadly into studies of accretion flows onto compact objects across a range of scales.

X-ray polarimetry is a frontier area that holds great promise for the measurement of spin. The polarization features of black hole disk radiation carry distinct and clear signatures of the effects of strong gravity and provide a third avenue for measuring the spins of numerous stellar-mass black holes.  Jack is a member of a team proposing to launch the first dedicated X-ray polarimeter, PRAXyS, which is undergoing Phase A study by NASA; black hole spin measurements are a core mission objective.

Honors and awards: 

Einstein Postdoctoral Fellowship, MIT, 2015-

Hubble Postdoctoral Fellow, Center for Astrophysics, 2012-2015

Fireman Prize Fellowship 2012

Harvard Merit Fellowship 2010

Harvard University Certicate of Distinction in Teaching 2008, 2010

Barry M. Goldwater Scholarship 2004, 2005

George Voinovich Center Research Scholarship 2003-2005

Robert Gescy Physics Scholarship 2002

Contact Information

t: 617-324-1194



PhD, Astronomy, Harvard, 2012; B.S., Astrophysics and Applied Mathematics, Ohio University, 2006