Bulk Motions of Filaments in the Local Universe

• Team Members:
  Hélène Courtois, Université Lyon 1
  R. Brent Tully, UH Institute for Astronomy
  J. Richard Fisher, National Radio Astronomy Observatory
  Nicolas Bonhomme, Université Lyon 1


• Project Description:
  Galaxies acquire motions that deviate from the universal expansion through gravitational interactions on a wide range of scales. The radial component of these deviant motions can be mapped with accurate measurements of distances. One of a variety of ways to measure distances makes use of the correlation between the luminosities of galaxies and their rotation rates. With appropriate photometric and spectroscopic information, the method can be applied to a majority of spiral galaxies. Samples of many thousands of galaxies can be acquired, giving the dense spatial coverage required to study the streams and eddies in the Cosmic Flow.
  
  Photometry to measure the luminosities of galaxies has been carried out at optical bands with telescopes at Mauna Kea Observatory and a tremendous advance is about to be realized with the implementation of digital all-sky surveys, foremost with Pan-STARRS in Hawai‘i. Information about galaxy rotation rates is derived from observations of global 21cm Hydrogen line profiles. Data are accumulated at a variety of telescopes to assure full sky coverage but foremost in importance for the project is the Robert C. Byrd Green Bank Telescope because of its sensitivity and access to most of the sky.
  
  The Extragalactic Distance Database (EDD) has been developed to give access to the diverse information involved with the measurement of galaxy distances. The results of observations made during the course of this program will be made available within the catalog ‘All Digital HI’ in EDD. Original optical photometry is made available in EDD through the catalog ‘Hawaii Photometry’.
  
  
• Publications
  “Our Peculiar Motion away from the Local Void”
  RB Tully, E.J. Shaya, ID Karachentsev, HM Courtois, DD Kocevski, L Rizzi, A Peel
  2008, ApJ, 676, 184
  
  “Distances in the Local Universe:
  New HI and I Band Surveys”
  HM Courtois, RB Tully, JR Fisher
  2007, BAAS, 38, 330
  
  “Derivation of Distances with the Tully-Fisher Relation:
  The Antlia Cluster”
  N Bonhomme, HM Courtois, RB Tully
  2008, arXiv:0806.1140