Reconstructed density and velocity fields from the 2MASS redshift survey

Pirin Erdogdu, Ofer Lahav, John Huchra, Matthew Colless, Roc Cutri, Emilio Falco, Teddy George, T Jarrett, David Jones, Lucas Macri, J Mader, Natalie Martimbeau, Michael Pahre, Quentin Parker, Anais Rassat, W Saunders

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Abstract

We present the reconstructed real-space density and the predicted velocity fields from the Two-Micron All-Sky Redshift Survey (2MRS). The 2MRS is the densest all-sky redshift survey to date and includes about 23 200 galaxies with extinction-corrected magnitudes brighter than Ks = 11.25. Our method is based on the expansion of these fields in Fourier-Bessel functions. Within this framework, the linear redshift distortions only affect the density field in the radial direction and can easily be deconvolved using a distortion matrix. Moreover, in this coordinate system, the velocity field is related to the density field by a simple linear transformation. The shot noise errors in the reconstructions are suppressed by means of a Wiener filter which yields a minimum variance estimate of the density and velocity fields. Using the reconstructed real-space density fields, we identify all major superclusters and voids. At 50 h-1 Mpc, our reconstructed velocity field indicates a backside infall to the Great Attractor region of vinfall = (491 A? 200) (I?/0.5)kms-1 in the Local Group frame and v infall = (64 A? 205) (I?/0.5)kms-1 in the cosmic microwave background (CMB) frame and I? is the redshift distortion parameter. The direction of the reconstructed dipole agrees well with the dipole derived by ErdoC?du et al. The misalignment between the reconstructed 2MRS and the CMB dipoles drops to 13A? at around 5000 km s-1 but then increases at larger distances.
Original languageEnglish
Pages (from-to)45 - 64
Number of pages20
JournalMonthly Notices of the Royal Astronomical Society
Volume373
Issue number1
DOIs
Publication statusPublished - 2006
Externally publishedYes

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