yt is a group effort.

Contributors:   
                Tom Abel (tabel@stanford.edu)
                Gabriel Altay (gabriel.altay@gmail.com)
                Kenza Arraki (karraki@gmail.com)
                Kirk Barrow (kssbarrow@gatech.edu)
                Ricarda Beckmann (Ricarda.Beckmann@astro.ox.ac.uk)
                Elliott Biondo (biondo@wisc.edu)
                Alex Bogert (fbogert@ucsc.edu)
                Robert Bradshaw (robertwb@gmail.com)
                André-Patrick Bubel (code@andre-bubel.de)
                Corentin Cadiou (corentin.cadiou@iap.fr)
                Pengfei Chen (madcpf@gmail.com)
                Yi-Hao Chen (yihaochentw@gmail.com)
                David Collins (dcollins4096@gmail.com)
                Brian Crosby (crosby.bd@gmail.com)
                Weiguang Cui (weiguang.cui@uwa.edu.au)
                Andrew Cunningham (ajcunn@gmail.com)
                Miguel de Val-Borro (miguel.deval@gmail.com)
                Bili Dong (qobilidop@gmail.com)
                Nicholas Earl (nchlsearl@gmail.com)
                Hilary Egan (hilaryye@gmail.com)
                Daniel Fenn (df11c@my.fsu.edu)
                John Forces (jforbes@ucolick.org)
                Adam Ginsburg (keflavich@gmail.com)
                Austin Gilbert (augilbert4@gmail.com)
                Sam Geen (samgeen@gmail.com)
                Nathan Goldbaum (goldbaum@ucolick.org)
                William Gray (graywilliamj@gmail.com)
                Markus Haider (markus.haider@uibk.ac.at)
                Eric Hallman (hallman13@gmail.com)
                David Hannasch (David.A.Hannasch@gmail.com)
                Axel Huebl (a.huebl@hzdr.de)
                Cameron Hummels (chummels@gmail.com)
                Anni Järvenpää (anni.jarvenpaa@gmail.com)
                Allyson Julian (astrohckr@gmail.com)
                Christian Karch (chiffre@posteo.de)
                Maximilian Katz (maximilian.katz@stonybrook.edu)
                Ben W. Keller (kellerbw@mcmaster.ca)
                Chang-Goo Kim (changgoo@princeton.edu)
                Ji-hoon Kim (me@jihoonkim.org)
                Steffen Klemer (sklemer@phys.uni-goettingen.de)
                Fabian Holler (anokfireball@poseto.de)
                Kacper Kowalik (xarthisius.kk@gmail.com)
                Mark Krumholz (mkrumhol@ucsc.edu)
                Michael Kuhlen (mqk@astro.berkeley.edu)
                Meagan Lang (langmm.astro@gmail.com)
                Erwin Tin-Hay Lau (ethlau@gmail.com)
                Doris Lee (dorislee@berkeley.edu)
                Eve Lee (elee@cita.utoronto.ca)
                Sam Leitner (sam.leitner@gmail.com)
                Stuart Levy (salevy@illinois.edu)
                Yuan Li (yuan@astro.columbia.edu)
                Chris Malone (chris.m.malone@gmail.com)
                Josh Maloney (joshua.moloney@colorado.edu)
                Jonah Miller (jonah.maxwell.miller@gmail.com)
                Chris Moody (cemoody@ucsc.edu)
                Stuart Mumford (stuart@mumford.me.uk)
                Andrew Myers (atmyers@astro.berkeley.edu)
                Jill Naiman (jnaiman@ucolick.org)
                Desika Narayanan (dnarayan@haverford.edu)
                Kaylea Nelson (kaylea.nelson@yale.edu)
                Jeff Oishi (jsoishi@gmail.com)
                Brian O'Shea (bwoshea@gmail.com)
                Jean-Claude Passy (jcpassy@uvic.ca)
                John Regan (john.regan@helsinki.fi)
                Sherwood Richers (srichers@tapir.caltech.edu)
                Mark Richardson (Mark.L.Richardson@asu.edu)
                Thomas Robitaille (thomas.robitaille@gmail.com)
                Anna Rosen (rosen@ucolick.org)
                Chuck Rozhon (rozhon2@illinois.edu)
                Douglas Rudd (drudd@uchicago.edu)
                Rafael Ruggiero (rafael.ruggiero@usp.br)
                Hsi-Yu Schive (hyschive@gmail.com)
                Anthony Scopatz (scopatz@gmail.com)
                Noel Scudder (noel.scudder@stonybrook.edu)
                Pat Shriwise (shriwise@wisc.edu)
                Devin Silvia (devin.silvia@gmail.com)
                Sam Skillman (samskillman@gmail.com)
                Stephen Skory (s@skory.us)
                Aaron Smith (asmith@astro.as.utexas.edu)
                Britton Smith (brittonsmith@gmail.com)
                Geoffrey So (gsiisg@gmail.com)
                Casey Stark (caseywstark@gmail.com)
                Antoine Strugarek (strugarek@astro.umontreal.ca)
                Ji Suoqing (jisuoqing@gmail.com)
                Elizabeth Tasker (tasker@astro1.sci.hokudai.ac.jp)
                Benjamin Thompson (bthompson2090@gmail.com)
                Robert Thompson (rthompsonj@gmail.com)
                Joseph Tomlinson (jmtomlinson95@gmail.com)
                Stephanie Tonnesen (stonnes@gmail.com)
                Matthew Turk (matthewturk@gmail.com)
                Rich Wagner (rwagner@physics.ucsd.edu)
                Michael S. Warren (mswarren@gmail.com)
                Andrew Wetzel (andrew.wetzel@yale.edu)
                John Wise (jwise@physics.gatech.edu)
                Michael Zingale (michael.zingale@stonybrook.edu)
                John ZuHone (jzuhone@gmail.com)

Several items included in the yt/extern directory were written by other
individuals and may bear their own license, including the progressbar module by
Nilton Volpato.  The PasteBin interface code (as well as the PasteBin itself)
was written by the Pocoo collective (pocoo.org).  
developed by Oliver Hahn.  

Thanks to everyone for all your contributions!