Michele Trenti's Research I: Galaxy Formation, Evolution and Dynamics


  • Until recently, the earliest stages of star and galaxies formation were mostly the realm of computer simulations and theoretical modeling. However, the installation of Hubble's Wide Field Camera 3 has changed the rules of the game, providing the first solid samples of galaxies into the epoch of reionization at redshift z>7, including my recent discovery of the farthest protocluster of galaxies. With the dynamic range of simulations and observations now approaching each other, there is a great advantage in bridging the gap between them. Therefore, I am using my theoretical and numerical expertize to drive the design of successful observations. In turn, I am not only resorting to observations to test predictions, but also to provide inspiration into further direct modeling. With many open questions, a large range of astrophysics involved, and an array of future computational and observational facilities coming online, the field is rich and promising for long-term research.

  • This approach has been highly successful: I am the Principal Investigator of The Brightest of Reionizing Galaxies (BoRG) survey. The project is based on two large allocations of HST time in Cycle 17 and Cycle 19. It has been an interesting journey to transition from theorist to PI of two programs that are among the 10 largest allocations of Hubble time in their cycle.

  • Exciting results from the BoRG survey are described on our collaboration website, and include two observational papers I lead (Survey Design and Farthest Protocluster Discovery).

  • I am also a Co-I of the WFC3 Hubble Ultradeep Field observations. Our team is publishing so many papers that it is best to consult ADS for the latest update.

  • Despite the growing involvement with observations I am still very interested in theoretical and numerical models for the formation of the first stars and galaxies. Some of my recent results are described in:

    Galaxy Formation in Heavily Overdense Regions at z ~ 10: The Prevalence of Disks in Massive Halos Romano-Diaz, Choi, Shlosman & Trenti 2011, ApJL, 738, 19
    The Clustering Properties of the First Galaxies Stiavelli & Trenti 2010, ApJL, 716, 190
    The Galaxy Luminosity Function During the Reionization Epoch Trenti et al. 2010, ApJL, 714, 202
    Extremely Metal-Poor Stars in the Milky Way: A Second Generation Formed After Reionization Trenti & Shull 2010, ApJ, 712, 435
    How Well do Cosmological Simulations Reproduce Individual Halo Properties? Trenti et al. 2010, ApJ, 711, 1198
    Metal-free Gas Supply at the Edge of Reionization: Late-epoch Population III Star Formation Trenti, Stiavelli & Shull 2009, ApJ, 700, 1672
    Formation Rates of Population III Stars and Chemical Enrichment of Halos during the Reionization Era Trenti & Stiavelli 2009, ApJ, 694, 879

  • Galaxies around z~6 QSOs: theory and observations:
    The Environments of High Redshift QSOs, Kim, Stiavelli, Trenti et al. 2009, ApJ, 695, 809
    The Dark Side of QSO Formation at High Redshifts Romano-Diaz, Shlosman, Trenti, Hoffman 2011, ApJ, 736, 1


  • Recently completed projects range from PopIII stars to Damped Lyman Alpha Systems.
    Neutral Gas Density in Damped Lyman Systems , Trenti & Stiavelli 2006, ApJ, 651, 51
    Dust Absorption Along the Line of Sight for High-Redshift Objects , Trenti & Stiavelli 2006, Apj, 651, 704
    Distribution of the Very First Population III Stars and Their Relation to Bright z~6 Quasars> , Trenti & Stiavelli 2007, ApJ, 667, 38
    The UDF05 Follow-up of the HUDF: I. The Faint-End Slope of the Lyman-Break Galaxy Population at z~5 , Oesch, Stiavelli, Carollo, Bergeron, Koekemoer, Lucas, Pavlovsky, Trenti, Lilly, Beckwith, and 7 coauthors 2007, ApJ, 671, 1212
    Cosmic Variance and Its Effect on the Luminosity Function Determination in Deep High-z Surveys , Trenti & Stiavelli 2008, ApJ, 676, 767. Be sure also to check out my Cosmic Variance Calculator .
    Where can we really find the First Stars' Remnants today?, Trenti, Santos & Stiavelli 2008, ApJ, 687, 1


  • My Ph.D. Thesis was centered on a theoretical and numerical investigation of the properties of collisionless stellar systems. My results on this are in:
    Thermodynamic Description of a Family of Partially Relaxed Stellar Systems , Bertin & Trenti 2003, ApJ, 584, 729
    A family of models of partially relaxed stellar systems. I. Dynamical properties , Trenti & Bertin 2005, A&A, 429, 161
    A family of models of partially relaxed stellar systems. II. Comparison with the products of collisionless collapse , Trenti, Bertin & van Albada 2005, A&A, 433, 57
    Partial Suppression of the Radial Orbit Instability in Stellar Systems , Trenti & Bertin 2006, ApJ, 637, 717


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