Research Directions

Research directions of the Center include theoretical astrophysics, with emphasis on computation and simulation; experimental astrophysics, with emphasis on the dark part of the universe and data mining; and particle physics, especially as related to the search for and theoretical understanding of dark matter particles at the LHC.

     Astrostatistics

     Astrostatistics is concerned with developing statistical techniques for
     the analysis of astrophysical data.  Carnegie Mellon has a unique
     established group of researchers in astrostatistics who have tackled a
     wide range of astrophysical problems. Recent research topics include:
     analysis of the Cosmic Microwave Background, estimating the dark energy
     equation of state, analysis of galaxy spectra, detecting galaxy clusters
     via the Sunyaev-Zeldovich effect, identifying filaments, and estimating
     density functions with truncated data.  A common theme in this work is
     the goal of detecting subtle, nonlinear signals in noisy,
     high-dimensional data.  The group plans to be deeply involved in future
     large surveys such as the LSST.

     Computer Science

      As petascale computing becomes a mainstay in many fields of scientific
      research, Computer Science researchers at Carnegie Mellon aim to
      develop the software, architectures, and community expertise to use these
      machines optimally. Emerging advances in multiscale modeling, simulation
      machine learning, data mining, and visualization can be
      exploited at the petascale for future scientific discovery. In particular,
      research focuses on developing data-intensive scalable computing (DISC)
      architectures and algorithms for managing and serving scientific data and computations
      to potentially very large user bases; developing scalable algorithms, data
      mining, and machine learning techniques for analyzing and gaining
      knowledge from massive amounts of data such as those to be gathered
      by the LSST; and developing the tools for doing cutting-edge numerical
      numerical simulations relevant to cosmology.

     Experimental Astrophysics

     From the study of the earliest energy emission in the universe - the
     Cosmic Microwave Background Radiation - to the evolution of galaxies and
     the formation of large-scale structure, Center researchers are part of
     the worldwide scientific effort to determine the basic cosmological
     parameters, investigate the nature of dark matter and dark energy, and to
     describe and understand the evolution of the universe.  Many of these
     parameters are expected to be tied down using data from current and
     planned ground-based and space-based observatories.  Carnegie Mellon has
     joined the collaboration building the Large Synoptic Survey Telescope,
     which will be the premier ground-based survey telescope in the next
     decade.  The analyses of these data sets are very challenging and will
     require both the development of highly sophisticated simulations and the
     application of the latest tools in data-mining, statistics, and computer
     science.  Carnegie Mellon is working as well on partnerships to build the
     Cylinder Radio Telescope to explore the universe, and especially the
     nature of dark energy, using the 21 cm radiation from neutral Hydrogen. 

    Theoretical Astrophysics

    Theoretical astrophysics research carried out at the Center focuses on the
    formation of structure in the universe and the role played by dark matter
    and dark energy. Large scale cosmological simulations are used as a tool
    to investigate the formation of galaxies and the growth and evolution of
    their associated super-massive black holes. The material in between
    galaxies is also an active area of study, as it contains the gas from
    which future stars will form. As we look back in time to the so called
    "dark ages" before the first stars formed, all these topics converge, and
    important roles are played by the first black holes, earliest galaxies and
    intergalactic gas in the re-ionization of the universe. This epoch is just
    beyond the current observational frontier, and theoretical predictions are
    being made for what will be seen, work made possible by the development of
    petascale simulation algorithms and physical modeling at the McWilliams
    Center.  The Center's dedicated computer cluster, Ferrari, and the Moore
    supercomputer shared with Computer Science will be important facilities in
    carrying out this research.

    Theoretical Particle Physics

     The LHC (Large Hadron Collider) will produce collisions of protons at
     energies never before reached. The products of these collisions could
     very well include the dark matter particles that compose twenty-three
     percent of the mass-energy in the universe. Indeed, there are compelling
     arguments that the energies at which the LHC operates are exactly in the
     window to see Weakly Interacting Massive Particles (WIMPs).  The
     remarkably successful Standard Model (SM) of particle physics however,
     does not include WIMPs, or any other realistic dark matter
     candidate. With data soon to come from the LHC, theorists in the Center
     will be part of the world-wide challenge to extend the SM in a way which
     is consistent with both the mathematics of quantum field theory and the
     bounds arising from laboratory experiments and cosmological
     observations. In particular, the discovery of a dark matter candidate
     would allow us to study its properties in a laboratory setting and,
     together with theoretical insights, to develop an underlying theory that
     encompasses both the SM and the new physics that includes dark matter.

     research

     Experimental Particle Physics

     Carnegie Mellon is one of 155 institutions involved in building and
     operating the Compact Muon Solenoid (CMS), one of the two major detectors
     at the Large Hadron Collider (LHC).  Carnegie Mellon physicists
     constructed the state-of-the-art electronics, consisting of 150,000
     channels, for the end-cap muon detectors of CMS.  A prime experimental
     activity at the LHC will be searching for, and hopefully studying, the
     properties of dark matter particles that may well be produced in this new
     energy regime. For example, a widely-studied candidate for the dark
     matter particles is the neutralino, if it is the lightest and most stable
     of a whole set of new supersymmetric partners to each of the particles of
     the Standard Model. Experimental particle physicists in the Center will
     be searching the CMS data for evidence of the neutralino or other
     possible dark matter particles, and then studying their properties once
     they are found.   

Research Collaborations

        The Large Synoptic Survey Telescope

      Carnegie Mellon joined the Large Synoptic Survey Telescope (LSST) collaboration early in 2008 as a participating institution.  The    LSST will be a new kind of telescope that combines a very wide field of view, moving quickly between images, and ability to observe very faint objects.  Located on a mountain ridge in the Chilean Andes, the LSST will take more than 800 panoramic pictures each night and cover the sky twice each week.  The 3.2 Giga-pixel camera will acquire about 20 Terabytes of data each night. Over the ten-year survey in six broad photometric bands starting in the middle of this decade, each region of the sky will be covered roughly 2000 times.   Fred Gilman is a member of the Board of Directors of the LSST Corporation.

November, 2009, The LSST Science Collaborations and project members have published a book documenting the science that can be done during the course of operation of the LSST. This LSST Science Book can be downloaded as a PDF file in its entirety (596 pages, over 50 Mb) or by chapter. The current version was made public on October 16, 2009. It is anticipated that it will be updated in a year or two. It can be downloaded by going to http://www.lsst.org/lsst/scibook

      The Sloan Digital Sky Survey

       Carnegie Mellon University joined  the Sloan Digital Sky Survey (SDSS) as full members in 2011. Cosmologists in the McWilliams Center are  focusing on the BOSS (Baryon Oscillation Spectroscopic Survey) experiment, which will constrain dark energy models and cosmic geometry. A new 1000 fiber multiplexed spectrograph has been installed on the 2.5 meter SDSS telescope at Apache Point, New Mexico. 10,000 square degrees of the sky are being surveyed over a 5 years period, resulting in a catalog containing 1.4 million Luminous Red Galaxy redshifts and 160,000 high redshift quasar spectra.  As an example of the power of the new survey it should be noted that in the latter case this represents a factor 50 improvement over the previous largest sample (from an earlier incarnation of the SDSS). By using this observational data to map out the baryon oscillation scale, which represents a "standard ruler," the Universe's distance scale will be measured to order 1% at redshifts z = 0.3 and z = 0.6 (using galaxies) and z = 2.5 (using the forest of Lyman alpha absorption seen in the quasar spectra). Alongside these cosmological constraints, the survey represents a rich source of data that will improve our knowledge of the formation of galaxies and of the intergalactic medium.  At the present time, large amounts of data have already been obtained and analyzed, and CMU scientists have taken part in the most recent data release, which includes the largest color image of the sky ever made, the first measurement of 3D structure in intergalactic space and measurement of galaxy clustering on the largest scales yet.