2MTF - V. Cosmography, β, and the residual bulk flow

Christopher M. Springob*, Tao Hong, Lister Staveley-Smith, Karen L. Masters, Lucas M. Macri, Bärbel S. Koribalski, D. Heath Jones, Tom H. Jarrett, Christina Magoulas, Pirin Erdoğdu

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    26 Citations (Scopus)
    21 Downloads (Pure)

    Abstract

    Using the Tully-Fisher relation, we derive peculiar velocities for the 2MASS Tully-Fisher survey and describe the velocity field of the nearby Universe. We use adaptive kernel smoothing to map the velocity field, and compare it to reconstructions based on the redshift space galaxy distributions of the 2MASS Redshift Survey (2MRS) and the IRAS Point Source Catalog Redshift Survey (PSCz). With a standard Χ2 minimization fit to the models, we find that the PSCz model provides a better fit to the 2MTF velocity field data than does the 2MRS model, and provides a value of β in greater agreement with literature values. However, when we subtract away the monopole deviation in the velocity zero-point between data and model, the 2MRS model also produces a value of β in agreement with literature values.We also calculate the 'residual bulk flow': the component of the bulk flow not accounted for by the models. This is ~250 km s-1 when performing the standard fit, but drops to ~150 km s-1 for both models when the aforementioned monopole offset between data and models is removed. This smaller number is more in line with theoretical expectations, and suggests that the models largely account for the major structures in the nearby Universe responsible for the bulk velocity.

    Original languageEnglish
    Pages (from-to)1886-1900
    Number of pages15
    JournalMonthly Notices of the Royal Astronomical Society
    Volume456
    Issue number2
    DOIs
    Publication statusPublished - 21 Feb 2016

    Bibliographical note

    Copyright 2015 The Authors. First published in Monthly Notices of the Royal Astronomical Society, 456(2), 1886-1900. The original publication is available at http://doi.org/10.1093/mnras/stv2648, published by Oxford University Press on behalf of the Royal Astronomical Society. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

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