Ravi Sheth
My work on halo abundances and clustering forms the basis of methods which use clusters (e.g., Xray luminosities, temperatures, the SunyaevZeldovich effects, galaxy velocity dispersions) to study cosmology. Recently, I extended the approach to predict how the morphology (sheets, filaments, voids) rather than simply the density, of large scale structure evolves, and how these predictions are modified if the initial conditions were nonGaussian, or if the force of gravity does not decrease as the inversesquare of separation.
I have played a leading role in the development of what is now the standard model of nonlinear clustering and biasing: the Halo Model. It is the currently the best language for interpreting measurements of weak lensing, the thermal and kinematic SunyaevZeldovich effects, and how galaxy clustering depends on galaxy type, both in real and in redshift space. In 2004, I showed that dark matter halo formation is correlated with environment; I also discussed why, and pointed out that understanding this correlation is necessary if the Halo Model is to be used as a precision tool for cosmology. This correlation was sufficiently unexpected and the consequences
sufficiently important that a number of groups have since confirmed that the effect does indeed exist: the effect is now called Assembly Bias.
In 2002, I developed a new method for estimating the evolution of the optical depth in the Lyman® forest. In 2005, I showed how to use Mark Correlations to quantify environmental trends in the galaxy distribution. More recently, I have developed methods for making unbiased estimates of the galaxy luminosity function and galaxy scaling relations from photometric redshift surveys. The methods can have broader impact, since they can be applied to studies where peculiar velocities are an important component of the observed redshift: these include using star counts to model the structure of our galaxy, and estimating the luminosity function of dwarf galaxies in our local (·50Mpc) neighborhood. And in 2012, I provided a simple formula for the first crossing distribution by walks with correlated steps which is accurate for a wide range of barrier shapes. I then showed how to extend it to treat ndimensional walks – thus providing the first realistic fully analytic model of nonlocal bias. In the process, I showed how to unify the Excursion Set and Peaks Theory descriptions of the Cosmic Web.
1990 – 1994 Ph.D. in Astrophysics, Marshall Scholar, Institute of Astronomy and Jesus College, University of Cambridge
1986 – 1990 BSc (High Honors) in Physics, Dana S. McGill Scholar, Haverford College
1983 – 1986 Four ‘IB’ HL certificates Kodaikanal International School, India
I develop physical models and statistical methods which allow the data from large scale galaxy and cluster surveys to constrain models of galaxy formation and cosmology.
An accurate tool for the fast generation of dark matter halo catalogs P. Monaco, E. Sefusatti, S. Borgani, M. Crocce, P. Fosalba, Ravi K. Sheth & T. Theuns. 2013 Monthly Notices of the Royal Astronomical Society, revised
On the selfconsistency of the excursion set approach I. Achitouv, Y. Rasera, Ravi K. Sheth & P.S. Corasaniti. 2013 Physical Review Letters, submitted (arXiv:1212.1166)
Stochastic bias in multidimensional excursion set approaches E. Castorina & Ravi K. Sheth. 2013 Monthly Notices of the Royal Astronomical Society, revised (arXiv:1301.5128)
Peakpeak correlations in the cosmic background radiation from cosmic strings M. S. Movahed, B.Javanmardi & Ravi K. Sheth. 2013 Monthly Notices of the Royal Astronomical Society, revised (arXiv:1212.0964)
Systematic effects on the luminosity size relation: Dependence on model fitting and morphology M. Bernardi, A. Meert, V. Vikram, M. HuertasCompany, S. Mei, F. Shankar & Ravi K. Sheth. 2013 Monthly Notices of the Royal Astronomical Society, revised (arXiv:1211.6122)
Ellipsoidal halo finders and implications for models of triaxial halo formation G. Despali, G. Tormen & Ravi K. Sheth. 2013 Monthly Notices of the Royal Astronomical Society, in press (arXiv:1212.4157)
Excursion set peaks: A selfconsistent model of dark halo abundances and clustering A. Paranjape, Ravi K. Sheth & V. Desjacques. 2013 Monthly Notices of the Royal Astronomical Society, in press (arXiv:1210.1483)
Nonlocal Lagrangian bias Ravi K. Sheth, K. C. Chan & R. Scoccimarro. 2013 Physical Review D, 87, 083002 (13 pages)
On the anisotropic density distribution on large scales P. Papai & Ravi K. Sheth. 2013 Monthly Notices of the Royal Astronomical Society, 429, 1133–1138
Measures of galaxy environment II  Rank ordered mark correlations R. Skibba, Ravi K. Sheth, et al. 2013 Monthly Notices of the Royal Astronomical Society, 429, 458–468
Scale dependent halo bias in the excursion set approach M. Musso, A. Paranjape, Ravi K. Sheth. 2012 Monthly Notices of the Royal Astronomical Society, 427, 3145–3158
Peaks theory and the excursion set approach A. Paranjape & Ravi K. Sheth. 2012 Monthly Notices of the Royal Astronomical Society, 426, 2789–2796
Lagrangian bias in the local bias model N. Frusciante & Ravi K. Sheth. 2012 Journal of Cosmology and Astroparticle Physics, 11, 016
Cosmic tides U.L. Pen, Ravi K. Sheth, J. HarnoisDeraps, X. Chen, Z. Li. 2012 Physical Review D, submitted (arXiv:1202.5804)
Courses Developed and Taught in Trieste:
Spring 2012 Cosmology ICTP Diploma
Spring 2012 Large Scale Structure SISSA PhD
Courses Developed and Taught at Penn:
Spring 2013 Survey of the Universe 125 nonscience majors
Spring 2010 The Big Bang and Beyond 60 nonscience majors
Fall 2009 The Big Bang and Beyond 25 freshman
Fall 2008 Survey of the Universe 60 nonscience majors
Spring 2008 The Big Bang and Beyond 15 nonscience majors
Fall 2007 The Big Bang and Beyond 13 nonscience majors
Spring 2007 Life in the Universe 19 nonscience majors
Fall 2006 The Big Bang and Beyond 115 nonscience majors
Spring 2006 Life in the Universe 26 nonscience majors
Fall 2005 Physics I: Mechanics and Waves 83 physics/engineering majors
Spring 2005 Mechanics, Dynamics and Chaos 4 graduate students
Courses Developed and Taught at Pitt:
Spring 2004 Stonehenge to Hubble 100 nonscience majors
Fall 2003 Introduction to Astronomy 100 physics majors
Spring 2003 Galactic and Extragalactic Astronomy 7 graduate students
Fall 2002 Introduction to Astronomy 100 physics majors
Spring 2002 Radiative Processes in Astrophysics 7 graduate students
Courses Developed and Taught Elsewhere:
Lecturer Galaxy surveys TIFR, India (December 2012)
Lecturer Structure formation STIAS, South Africa (Jan 2012)
Visiting Lecturer Nonlinear clustering HRI, India (February 2009)
Invited Lecturer XIII BSCG Rio de Janiero, Brazil (July 2008)
PIRE Lecturer Hierarchical structure formation Santiago, Chile (March 2007)
Invited Lecturer Galaxies and Cosmology University of Padova (January 2007)
NOVA Lecturer The halo model The Netherlands (November 2006)
Senior Visiting Scholar AIMS, Cape Town South Africa (2012–2015)
Visiting Professor LUTH  Meudon Observatory France (June 2012)
Visiting Professor GEPI  Meudon Observatory France (June 2011)
Visiting Scholar IPhTCEA Saclay, France (June 2010)
Visiting Professor APC, Paris 7 Diderot Paris, France (June 2009)
Events

High Energy Seminar: "Modular spacetime and Metastring theory"
April 3, 2017  2:00 pm
Djordje Minic (Virginia Tech)
DRL 2N36

Dissertation Defense: "Supernova Cosmology and How to Talk About It: New Approaches to Cosmological Parameter Inference with Type Ia Supernovae and an Assessment of the Education and Public Outreach Program of The Dark Energy Survey"
April 3, 2017  2:00 pm
Rachael CaneWolf (UPenn)
DRL 3W2

MathBio seminar: " The mathematical foundation of a landscape theory for living matters and life"
April 3, 2017  4:00 pm
Hong Qian (University of Washington)
Carolyn Lynch Laboratory, 318