Michael Troxel has always liked puzzles, especially challenging ones. Which is fortunate, since his job is solving some of the most perplexing, fundamental mysteries of the universe.
At some point in middle school I asked myself, Whats the hardest thing that I could try to do? he said. And at that point the hardest thing I knew about was astrophysics, so I think that was probably the first motivation for choosing this career, if Im honest. But that was before I understood what it actually meant.
A cosmologist and assistant professor in the Department of Physics, Troxel has spent the past two years as the cosmology analysis coordinator in the Dark Energy Surveyan international collaboration involving 500 scientists analyzing a massive dataset of about 400 million celestial objects. It has been what I think is one of the most complex and difficult analyses ever performed in cosmology, which has only been possible with the contributions and leadership of dozens of my colleagues, Troxel said. The outcome will span about 30 published research papers with more than 200 contributing scientists.
Today, in recognition of his contributions to the field, Troxel was granted an award through the Department of Energy Early Career Research Program. Founded to bolster the nations scientific workforce by providing support to exceptional researchers during crucial early career years, when many scientists do their most formative work, the program will support 76 scientists in 2020. It is a welcome validation that my time supporting this project has been well spent, Troxel said. It will also give my research group the resources to tackle some of the hardest problems we face in cosmology.
The award offers five years of funding for a specific project, which Troxel will partly use to support his work on a successor to the Dark Energy Survey: research using the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST), which is scheduled to begin operations in 2023, within the Dark Energy Science Collaboration (DESC). Located in Cerro Pachon, Chile, the facility is one of the three large, state-of-the-art telescopes that will come online in the coming decade, including the Nancy Grace Roman Space Telescope that Troxels group also works with. Rubin and Roman will do many of the same things that the Dark Energy Survey does, but 10 times better, Troxel said.
This DES collaboration map of dark matter was made from gravitational lensing measurements. Credit: Chihway Chang/Kavli Institute for Cosmological Physics at the University of Chicago/DES Collaboration
All focus, in part, on the two most pressing cosmological mysteries left to solve: dark matter and dark energy. Theyre the pieces of the universe that we just dont understand, Troxel said. And a bit frighteningly, they seem to make up 95 percent of the universe.
The first, dark matter, is difficult to research because scientists have yet to see itit doesnt interact with light in the way ordinary matter does. But it does interact with gravity, and current astrophysical modelswhich have been very successful at predicting how the universe has evolvedimply that there is five times as much matter as we can see in the form of this dark matter.
Troxel specializes in gravitational lensing, or how gravity bends the path of light and distorts images of distant galaxies. By taking large-scale images of the universe from observatories like Rubin and Roman and analyzing those distortions, he can map where dark matter is located. Through the Dark Energy Survey, Troxel and others have made such maps for about an eighth of the sky. Rubin will allow them to map the entire southern hemisphere.
The other mystery, dark energy, involves the expansion of the universe. Since the Big Bang, all of the universes cosmological objects have been moving away from each other. Until the last few decades, scientists largely expected that the objects would slow down due to the gravitational force pulling them back together. But the opposite is happening.
What we observed is that instead of slowing down, everything is speeding up and accelerating away from each other, Troxel said. This is like throwing a ball up in the air and instead of having it fall back down, it starts shooting up faster and faster.
Duke cosmologists pose together. Troxel is third from left. Walter is to his right and Scolnic is the last on the right. Credit: Duke University
Since the acceleration is inexplicable through gravity from massive objects, scientists have concluded that there must be another force or component of the universe at play. In fact, this other component of the universe makes up 70 percent of the dynamics of the universe, Troxel said. It is also invisible to observation, but through gravitational lensing, Troxel and his colleagues can use data from the Rubin and other telescopes to learn more about it.
With the funding from his Department of Energy Award, Troxel said he will be able to hire another graduate student and postdoc to support Dukes cosmology research, which also includes professors Dan Scolnic and Chris Walter, expanding the departments recent focus on the field. One of the benefits for students is that they will have the opportunity to visit the observatory in Chile as the commissioning of Rubin starts.
Its those opportunities to support future scientists that are most meaningful to Troxel. A first-generation student, Troxel credits those who supported his career for his current success. My path to where I am now was not easy, and I only made it due to the support of my teachers and mentors, he said.
But he also hopes to welcome a more diverse group of students into cosmology. It was only last week [with the US Supreme Court ruling on Title VII], for the first time in my life, that I am protected at the national level from being fired from my job solely for who I am, said Troxel, who is LGBTQ.
The story of modern physics and cosmology has been one of turning around our perspectives and viewing the physical world in a new light, leading to fundamental new insights about how the world works, he added. Physics and cosmology benefit from new and diverse perspectives, but we must ensure that the field is worthy of those new voices. The most rewarding part of my role now as a teacher at Duke is to help make sure the next generation of diverse voices are heard and supported while they find their own paths to grappling with the mysteries of the universe.
See more here:
Exploring the Fundamental Mysteries of the Universe by Seeing the Invisible - SciTechDaily
- Rotational spectra of isotopic species of methyl cyanide, CH_3CN, in their ground vibrational states up to terahertz frequencies - November 8th, 2009 [November 8th, 2009]
- Cosmological parameter extraction and biases from type Ia supernova magnitude evolution - November 8th, 2009 [November 8th, 2009]
- Continuous monitoring of pulse period variations in Hercules X-1 using Swift/BAT - November 8th, 2009 [November 8th, 2009]
- Constraining the ortho-to-para ratio of H{_2} with anomalous H{_2}CO absorption - November 8th, 2009 [November 8th, 2009]
- A photometric and spectroscopic study of the new dwarf spheroidal galaxy in Hercules - Metallicity, velocities, and a clean list of RGB members - November 8th, 2009 [November 8th, 2009]
- Luminosities and mass-loss rates of SMC and LMC AGB stars and red supergiants - November 8th, 2009 [November 8th, 2009]
- Electron beam – plasma system with the return current and directivity of its X-ray emission - November 8th, 2009 [November 8th, 2009]
- The propagation of the shock wave from a strong explosion in a plane-parallel stratified medium: the Kompaneets approximation - November 8th, 2009 [November 8th, 2009]
- Analysis of hydrogen-rich magnetic white dwarfs detected in the Sloan Digital Sky Survey - November 8th, 2009 [November 8th, 2009]
- Letter: Centaurus A as TeV \gamma-ray and possible UHE cosmic-ray source - November 8th, 2009 [November 8th, 2009]
- Young pre-low-mass X-ray binaries in the propeller phase - Nature of the 6.7-h periodic X-ray source 1E 161348-5055 in RCW 103 - November 8th, 2009 [November 8th, 2009]
- Radiative rates and electron impact excitation rates for transitions in Cr VIII - November 8th, 2009 [November 8th, 2009]
- Solar granulation from photosphere to low chromosphere observed in Ba II 4554 Å line - November 8th, 2009 [November 8th, 2009]
- Does the HD 209458 planetary system pose a challenge to the stellar atmosphere models? - November 8th, 2009 [November 8th, 2009]
- Effect of asymmetry of the radio source distribution on the apparent proper motion kinematic analysis - November 8th, 2009 [November 8th, 2009]
- Destriping CMB temperature and polarization maps - November 8th, 2009 [November 8th, 2009]
- Search for cold debris disks around M-dwarfs. II - November 8th, 2009 [November 8th, 2009]
- Precise data on Leonid fireballs from all-sky photographic records - November 8th, 2009 [November 8th, 2009]
- An X-ray view of 82 LINERs with Chandra and XMM-Newton data - November 8th, 2009 [November 8th, 2009]
- Radio observations of ZwCl 2341.1+0000: a double radio relic cluster - November 8th, 2009 [November 8th, 2009]
- Candidate free-floating super-Jupiters in the young \sigma Orionis open cluster - November 8th, 2009 [November 8th, 2009]
- The metallicity gradient as a tracer of history and structure: the Magellanic Clouds and M33 galaxies - November 8th, 2009 [November 8th, 2009]
- XMMSL1 J060636.2-694933: an XMM-Newton slew discovery and Swift/Magellan follow up of a new classical nova in the LMC - November 8th, 2009 [November 8th, 2009]
- The inner rim structures of protoplanetary discs - November 8th, 2009 [November 8th, 2009]
- The solar Ba{\sf II} 4554 Å line as a Doppler diagnostic: NLTE analysis in 3D hydrodynamical model - November 8th, 2009 [November 8th, 2009]
- Magnetic evolution of superactive regions - Complexity and potentially unstable magnetic discontinuities - November 8th, 2009 [November 8th, 2009]
- Low-mass protostars and dense cores in different evolutionary stages in IRAS 00213+6530 - November 8th, 2009 [November 8th, 2009]
- PMAS optical integral field spectroscopy of luminous infrared galaxies - I. The atlas - November 8th, 2009 [November 8th, 2009]
- First AGILE catalog of high-confidence gamma-ray sources - November 8th, 2009 [November 8th, 2009]
- Radiative hydrodynamics simulations of red supergiant stars - I. interpretation of interferometric observations - November 8th, 2009 [November 8th, 2009]
- Extrasolar planets and brown dwarfs around A–F type stars - VII. \theta Cygni radial velocity variations: planets or stellar phenomenon? - November 8th, 2009 [November 8th, 2009]
- Cosmic rays and the magnetic field in the nearby starburst galaxy NGC 253 - II. The magnetic field structure - November 8th, 2009 [November 8th, 2009]
- Physical structure and water line spectrum predictions of the intermediate mass protostar OMC2-FIR4 - November 8th, 2009 [November 8th, 2009]
- The bright galaxy population of five medium redshift clusters - II. Quantitative galaxy morphology - November 8th, 2009 [November 8th, 2009]
- Dust in brown dwarfs and extra-solar planets - II. Cloud formation for cosmologically evolving abundances - November 8th, 2009 [November 8th, 2009]
- The quiet Sun magnetic field observed with ZIMPOL on THEMIS - I. The probability density function - November 8th, 2009 [November 8th, 2009]
- Complexity in the sunspot cycle - November 8th, 2009 [November 8th, 2009]
- Properties and nature of Be stars - 26. Long-term and orbital changes of \zeta Tauri - November 8th, 2009 [November 8th, 2009]
- The massive Wolf-Rayet binary LSS 1964 (=WR 29) - II. The V light curve - November 8th, 2009 [November 8th, 2009]
- Supernova progenitor stars in the initial range of 23 to 33 solar masses and their relation with the SNR Cassiopeia A - November 8th, 2009 [November 8th, 2009]
- The Hertzsprung-Russell Diagram of Star Clusters - November 8th, 2009 [November 8th, 2009]
- Table of the 10 Brightest stars within 10 Parsecs of the Sun - November 8th, 2009 [November 8th, 2009]
- The Hertzsprung-Russell Diagram of the Nearest Stars - November 8th, 2009 [November 8th, 2009]
- Magnitude and Color in Astronomy - November 8th, 2009 [November 8th, 2009]
- Stellar Types - November 8th, 2009 [November 8th, 2009]
- Brown Dwarfs - November 8th, 2009 [November 8th, 2009]
- Spotting the Minimum - November 8th, 2009 [November 8th, 2009]
- The Structure and Evolution of Brown Dwarfs - November 8th, 2009 [November 8th, 2009]
- No Bang from the Big Bang Machine - November 8th, 2009 [November 8th, 2009]
- The Sizes of the Stars and the Planets - November 8th, 2009 [November 8th, 2009]
- An Implausible Light Thrust - November 8th, 2009 [November 8th, 2009]
- the Masses of Degenerate Objects - November 8th, 2009 [November 8th, 2009]
- Degeneracy Pressure - November 8th, 2009 [November 8th, 2009]
- Introduction to Degenerate Objects - November 8th, 2009 [November 8th, 2009]
- The Radii of Degenerate Objects - November 8th, 2009 [November 8th, 2009]
- The Inevitability of Black Holes - November 8th, 2009 [November 8th, 2009]
- Scientific Pig-Out - November 8th, 2009 [November 8th, 2009]
- The Neutrino Cooling of Degenerate Dwarfs - November 8th, 2009 [November 8th, 2009]
- The Neutrino Cooling of Neutron Stars - November 8th, 2009 [November 8th, 2009]
- Overview of Supernovae - November 8th, 2009 [November 8th, 2009]
- Energetics of Thermonuclear Supernovae - November 8th, 2009 [November 8th, 2009]
- Thermonuclear Supernovae - November 8th, 2009 [November 8th, 2009]
- Nuclear Reactions in Thermonuclear Supernovae - November 8th, 2009 [November 8th, 2009]
- Core-Collapse Supernovae - November 8th, 2009 [November 8th, 2009]
- Neutrinos and SN 1987A - November 8th, 2009 [November 8th, 2009]
- Revealing the sub-AU asymmetries of the inner dust rim in the disk around the Herbig Ae star R Coronae Austrinae - December 13th, 2009 [December 13th, 2009]
- Probing the dust properties of galaxies up to submillimetre wavelengths - I. The spectral energy distribution of dwarf galaxies using LABOCA - December 13th, 2009 [December 13th, 2009]
- On the physical origin of the second solar spectrum of the Sc II line at 4247 Å - December 13th, 2009 [December 13th, 2009]
- On detecting the large separation in the autocorrelation of stellar oscillation times series - December 13th, 2009 [December 13th, 2009]
- Imaging the spotty surface of Betelgeuse in the H band - December 13th, 2009 [December 13th, 2009]
- Chandra observation of Cepheus A: the diffuse emission of HH 168 resolved - December 13th, 2009 [December 13th, 2009]
- A planetary eclipse map of CoRoT-2a - Comprehensive lightcurve modeling combining rotational-modulation and transits - December 13th, 2009 [December 13th, 2009]
- The chemical composition of carbon stars. The R-type stars - December 13th, 2009 [December 13th, 2009]
- Flow instabilities of magnetic flux tubes - IV. Flux storage in the solar overshoot region - December 13th, 2009 [December 13th, 2009]
- Fragmentation of a dynamically condensing radiative layer - December 13th, 2009 [December 13th, 2009]
- Temporal variations of the CaXIX spectra in solar flares - December 13th, 2009 [December 13th, 2009]
- Deuterium chemistry in the Orion Bar PDR - “Warm” chemistry starring CH_{2}D^+ - December 13th, 2009 [December 13th, 2009]
- Metal abundances in the cool cores of galaxy clusters - December 13th, 2009 [December 13th, 2009]
- The nature of the X-ray binary IGR J19294+1816 from INTEGRAL, RXTE, and Swift observations - December 13th, 2009 [December 13th, 2009]
- Relating basic properties of bright early-type dwarf galaxies to their location in Abell 901/902 - December 13th, 2009 [December 13th, 2009]