CaltechAUTHORS
Published June 1, 2006 | Version Published
Journal Article Open

The dipole anisotropy of the 2 Micron All-Sky Redshift Survey

Creators

  • 1. ROR icon Middle East Technical University
  • 2. ROR icon University of Nottingham
  • 3. ROR icon Harvard-Smithsonian Center for Astrophysics
  • 4. ROR icon University College London
  • 5. ROR icon Infrared Processing and Analysis Center
  • 6. ROR icon Jet Propulsion Lab
  • 7. ROR icon The Ohio State University
  • 8. ROR icon NOIRLab
  • 9. ROR icon W.M. Keck Observatory
  • 10. ROR icon Macquarie University
  • 11. ROR icon Royal Observatory

Abstract

We estimate the acceleration on the Local Group (LG) from the 2 Micron All-Sky Redshift Survey (2MRS). The sample used includes about 23 200 galaxies with extinction-corrected magnitudes brighter than Ks= 11.25 and it allows us to calculate the flux-weighted dipole. The near-infrared flux-weighted dipoles are very robust because they closely approximate a mass-weighted dipole, bypassing the effects of redshift distortions and require no preferred reference frame. This is combined with the redshift information to determine the change in dipole with distance. The misalignment angle between the LG and the cosmic microwave background (CMB) dipole drops to 12°± 7° at around 50 h^−1 Mpc, but then increases at larger distances, reaching 21°± 8° at around 130 h^−1 Mpc . Exclusion of the galaxies Maffei 1, Maffei 2, Dwingeloo 1, IC342 and M87 brings the resultant flux dipole to 14°± 7° away from the CMB velocity dipole. In both cases, the dipole seemingly converges by 60 h^−1 Mpc. Assuming convergence, the comparison of the 2MRS flux dipole and the CMB dipole provides a value for the combination of the mass density and luminosity bias parameters Ω0.6m/bL= 0.40 ± 0.09.

Additional Information

© 2006 The Authors. Journal compilation © 2006 RAS. Accepted 2006 February 23. Received 2005 December 13; in original form 2005 June 30. Published Online: 13 April 2006. We thank Sarah Bridle, Alan Heavens, Ariyeh Maller and Karen Masters for their useful comments. PE would like to thank the University College London for its hospitality during the completion of this work. OL acknowledges a PPARC Senior Research Fellowship. JPH, LM, CSK, NM and TJ are supported by NSF grant AST-0406906, and EF's research is partially supported by the Smithsonian Institution. DHJ is supported as a Research Associate by Australian Research Council Discovery-Projects Grant (DP-0208876), administered by the Australian National University. This publication makes use of data products from the 2MASS, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. This research has also made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration and the SIMBAD database, operated at CDS, Strasbourg, France.

Attached Files

Published - ERDmnras06a.pdf

Files

ERDmnras06a.pdf

Files (1.9 MB)

Name Size
md5:5f32272a5e04df742778304a5b8cc41b
1.9 MB Preview Download

Additional details

Identifiers

Eprint ID
13000
Resolver ID
CaltechAUTHORS:ERDmnras06a

Funding

Particle Physics and Astronomy Research Council (PPARC)
NSF
AST-0406906
Smithsonian Institution
Australian Research Council
DP-0208876
Australian National University
NASA

Dates

Created
2009-01-15
Created from EPrint's datestamp field
Updated
2021-11-08
Created from EPrint's last_modified field

Caltech Custom Metadata

Caltech groups
Infrared Processing and Analysis Center (IPAC)