Data from the numerical relativity group at NASA Goddard Space Flight Center (of which I was a member from 2004-2010), visualization by Chris Heinze.

Image I made for Physical Review Letters to highlight my analytical solution for merging black-hole binaries.

Press Coverage:

  1. *Science, the APS, Phys.Org, and a bunch of others in the US and around the world had articles on my analytical solution for merging black-hole binaries. The Eberly College at WVU also had a nice feature article.

  2. *Sky & Telescope, New Scientist, and the MIT Tech Review had articles on my work on galaxy/black hole evolution and pulsar timing arrays

  3. *The New York Times covered the work of the NASA Goddard numerical relativity group, of which I was a member at the time.

Other research items:

  1. *My CV (updated December 4, 2019) and an always up-to-date list of my publications

  2. *A talk I gave at the Perimeter Institute in Canada on estimating the signal from supermassive black-hole binaries that will be seen with pulsar timing arrays

  3. *A pulsar timing array review talk I gave at the Kavli Institute for Theoretical Physics in Santa Barbara, CA

  4. *A numerical relativity review talk I gave at the Perimeter Institute

  5. *A massive black-hole binary astrophysics talk I gave at Universitat de les Illes Balears in Mallorca, Spain

  6. *Video links from the PCTS conference I organized on gravitational waves and electromagnetic counterparts

I have been fortunate to learn/work/teach at several of the finest schools in the country (as well as a national lab of some renown).  The insignia of my stops along the way are above, in reverse chronological order.  In the broadest of terms, I am a theoretical astrophysicist.  More specifically, I am a gravitational wave astronomer, numerical and analytical relativist, and data analyst.  My research focuses mainly on understanding the dynamics of compact binaries, which are systems composed of any combination of black holes, neutron stars, and white dwarfs.  Through numerical simulation and/or analytical modeling, I estimate the behavior of two of these highly dense, tightly orbiting bodies.  Such systems stretch Einstein’s theory of general relativity to its limit.  Among the many interesting features of these systems is their emission of gravitational waves (upper movie), whereby space itself is actually made to ripple, and the potential for simultaneous electromagnetic emission, for example from the interaction of a black hole with a circumbinary accretion disk (lower movie).

In 2015, the Advanced Laser Interferometer Gravitational Wave Observatory (LIGO, came online.  Almost immediately, we detected a signal from two ~30 solar mass black holes merging!  We have released the data at, and the detection paper and companion papers can be found at  I was featured in a short video talking about the discovery.  As Advanced LIGO approaches its full design sensitivity in the next few years, we expect it will detect signals routinely. 

Meanwhile, the NANOGrav pulsar timing array (NANOGrav PTA, is in operation, and has already collected over 9 years of data.  Within the next 5 years, both Advanced LIGO (in coordination with Europe’s Advanced Virgo) and NANOGrav (in coordination with the European and Parkes PTAs) will likely achieve  detection of gravitational waves. 

Then, in ~2032, the Laser Interferometer Space Antenna (LISA, will fly.  LISA will observe, among other things, the merging of supermassive black holes at the centers of colliding galaxies, and it will observe them as far away (and therefore as far back in time) as galaxies have existed.  LISA was to be a joint NASA/ESA mission until funding realities derailed those plans.  ESA committed to go it alone initially, but NASA has since rejoined as a junior partner. ESA selected LISA as its third large mission, slated to launch in 2034, but very recently, ESA committed to a budget that could move up LISA’s launch to 2032, to ensure overlap with the Athena mission, the second prioritized large mission that is an X-ray observatory and will also target emission from massive black holes.  Meanwhile, hopes are high that the US astronomical community will strongly endorse LISA in the next decadal survey, which would motivate NASA to fund LISA to the fullest extent that ESA and the U.S. Congress will allow.

My research has primarily contributed to the science of these three missions, with occasional detours to invent new mission concepts, as well as detours that have nothing to do with gravitational waves.  For full details, see the links to some of my talks, as well as my CV and list of publications, to the right.