Dr. Warren R. Brown
wbrown @ cfa.harvard.edu
(617) 496-7905
60 Garden St, Mail Stop 20, Cambridge, MA 02138

I am an astronomer at the Smithsonian. I am best known for my Hypervelocity Star discoveries, stars ejected from our galaxy by the Milky Way's central massive black hole. With Mukremin Kilic, I am leading a targeted survey for merging pairs of white dwarfs that may one day explode as supernovae and that are currently the strongest known sources of gravitational waves.

I direct the Smithsonian's Telescope Data Center and I am involved in building new instruments for our ground-based telescopes. I am PI of the SAO Widefield InfraRed Camera (SWIRC), a near-infrared imager for the f/5 MMT that I took from proposal to commissioning in 13 months. I am co-PI of the MMT Magellan Infrared Spectrograph and Project Scientist of the proposed Giant Magellan Telescope Near Infrared MultiObject Spectograph. My newest instrument is the MMT Cam optical imager.

Hypervelocity Stars!

I discovered the first hypervelocity star, a star whose extreme 1.5 million mph speed can be explained only by a slingshot from the Galaxy's central black hole. The hypervelocity star is an outcast, exiled to drift in the empty depths of space. I have since discovered 16 unbound stars in a targeted survey, first announced here.

The two most fascinating aspects of hypervelocity stars are their link to the central black hole, and the fact that they have traveled out over 200,000 light years allowing us measure the dark matter that surrounds the Milky Way. To hear the big picture, listen to the New Scientist podcast or the American Physical Society podcast.

In 2007 I was awarded Harvard's Bok Prize "for outstanding work in the discovery of hypervelocity stars, a new class of objects in the Milky Way." In 2008 I was awarded the Smithsonian Secretary's Research Prize for my "successful targeted survey for hypervelocity stars." This invited review article in the Galactic Center Newsletter summarizes the knowledge of hypervelocity stars as of 2009, and the July 2011 Astronomy Beat column published by the Astronomical Society of the Pacific describes my hypervelocity star research to a general public audience.

We are now using the Hubble Space Telescope to measure the proper motions of hypervelocity stars. The first trajectory we measured points directly from the center of the Milky Way. Another recent result is about the age and flight time of HVS 17, as described in the December 2013 Scientific American.

Merging White Dwarfs!

The Hypervelocity Star Survey has also discovered under-weight white dwarfs in compact pairs: they are the strongest known sources of gravitational waves and are possible supernovae progenitors.

In 2011 we discovered a record-breaking detached pair of white dwarfs with a 12.75 minute orbital period. This system is a gravitational wave source 10,000 times stronger than the Hulse-Taylor pulsar and will merge in less than 1 million years. It's rapid change in orbital period will provide a fundamental test of general relativity as described by Cosmos magazine, Sky and Telescope, and National Geographic.

My CURRICULUM VITAE (updated Spring 2014).
Refereed Scientific Publications:

Hypervelocity Stars

  • MMT Hypervelocity Star Survey III: The Complete Survey .pdf
  • The Origin of HVS17, an Unbound Main Sequence B Star at 50 kpc .pdf
  • The Nature of Hypervelocity Stars and the Time Between Their Formation and Ejection .pdf
  • MMT Hypervelocity Star Survey. II. Five New Unbound Stars .pdf
  • Binary Disruption by Massive Black Holes: Hypervelocity Stars, S Stars, and Tidal Disruption Events .pdf
  • A Galactic Center Origin for HE 0437-5439, the Hypervelocity Star near the Large Magellanic Cloud .pdf
  • Runaway Stars, Hypervelocity Stars, and Radial Velocity Surveys .pdf
  • The Anisotropic Spatial Distribution of Hypervelocity Stars .pdf
  • MMT Hypervelocity Star Survey .pdf
  • HVS 7: a chemically peculiar hypervelocity star .pdf
  • Hypervelocity Stars: From the Galactic Center to the Halo .pdf
  • Hypervelocity Stars. III. The Space Density and Ejection History of Main Sequence Stars from the Galactic Center .pdf
  • Hypervelocity Stars. II. The Bound Population .pdf
  • Hypervelocity Stars. I. The Spectroscopic Survey .pdf
  • Hypervelocity Stars: Predicting the Spectrum of Ejection Velocities .pdf
  • A Successful Targeted Search for Hypervelocity Stars .pdf
  • Merging White Dwarfs

  • A new gravitational wave verification source
  • Radius Constraints from High-speed Photometry of 20 Low-mass White Dwarf Binaries
  • SDSS J0745: Discovery of a Metal-Rich and Tidally Distorted Extremely Low Mass White Dwarf
  • The ELM Survey. V. Merging Massive White Dwarf Binaries
  • Rapid Orbital Decay in the 12.75-minute WD+WD Binary J0651+2844
  • The ELM Survey. IV. 24 White Dwarf Merger Systems
  • Two New Tidally Distorted White Dwarfs
  • The ELM Survey. III. A Successful Targeted Survey for Extremely Low Mass White Dwarfs
  • The Shortest Period Detached Binary White Dwarf System
  • The Binary Fraction of Low-mass White Dwarfs
  • The Merger Rate of Extremely Low Mass White Dwarf Binaries: Links to the Formation of AM CVn Stars and Underluminous Supernovae
  • The ELM Survey. II. Twelve Binary White Dwarf Merger Systems
  • The ELM Survey. I. A Complete Sample of Extremely Low-mass White Dwarfs
  • The Discovery of Binary White Dwarfs that will Merge within 500 Myr
  • The Runaway White Dwarf LP40022 has a Companion
  • The Discovery of a Companion to the Lowest Mass White Dwarf
  • The Lowest Mass White Dwarf
  • Century Survey Galactic Halo Project

  • The Most Distant Stars in the Milky Way
  • Identifying Star Streams in the Milky Way Halo
  • The Mass Profile of the Galaxy to 80 kpc .pdf
  • Velocity Dispersion Profile of the Milky Way Halo .pdf
  • The Century Survey Galactic Halo Project III: A Complete 4300 sq. deg. Survey of Blue Horizontal Branch Stars in the Metal-Weak Thick Disk and Inner Halo .pdf
  • The Century Survey Galactic Halo Project II: Global Properties and the Luminosity Function of Field Blue Horizontal Branch Stars .pdf
  • Mapping the Inner Halo of the Galaxy with 2MASS-Selected Horizontal Branch Candidates .pdf
  • The Century Survey Galactic Halo Project I: Stellar Spectral Analysis .pdf

  • Galaxies

  • MMT Extremely Metal Poor Galaxy Survey I. An Efficient Technique to Identify Metal Poor Galaxies
  • Stellar Velocity Dispersion of the Leo A Dwarf Galaxy
  • SDSS 0809+1729: Connections Between Extremely Metal-Poor Galaxies and Gamma-Ray Burst Hosts
  • V and R-band Galaxy Luminosity Functions and Low Surface Brightness Galaxies in the Century Survey
  • UV Excess Galaxies: Wolf-Rayet Galaxies

  • Instrumentation

  • MMT and Magellan Infrared Spectrograph
  • Smithsonian Widefield Infrared Camera .pdf
  • The Cryogenic Refractive Indices of S-FTM16, a Unique Optical Glass for Near-Infrared Instruments .pdf
  • A Detailed Thermal Analysis of the Binospec Spectrograph
  • SPIE paper on my design recommendations for Binospec

  • Here is a link to my ancient cheat sheet, "Grad Student Time-Saving Tools", that summarizes computer tips for astronomers.
    Before Grad School