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arXiv · 1409.0287

2MTF IV. A bulk flow measurement of the local Universe

Tao Hong·Christopher M. Springob·Lister Staveley-Smith·Morag I. Scrimgeour·Karen L. Masters·Lucas M. Macri·Bärbel S. Koribalski·D. Heath Jones·Tom H. Jarrett
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Abstract

Using the 2MASS near-infrared photometry and high signal-to-noise HI 21-cm data from the Arecibo, Green Bank, Nancay, and Parkes telescopes, we calculate the redshift-independent distances and peculiar velocities of 2,018 bright inclined spiral galaxies over the whole sky. This project is part of the 2MASS Tully-Fisher survey (2MTF), aiming to map the galaxy peculiar velocity field within 100 h^{-1}Mpc, with an all-sky coverage apart from Galactic latitudes |b|< 5 deg. A χ^2 minimization method was adopted to analyze the Tully-Fisher peculiar velocity field in J, H and K bands, using a Gaussian filter. We combine information from the three wavebands, to provide bulk flow measurements of 310.9 +/- 33.9 km/s, 280.8 +/- 25.0 km/s, and 292.3 +/- 27.8 km/s at depths of 20 h^{-1}Mpc, 30 h^{-1}Mpc and 40 h^{-1}Mpc, respectively. Each of these bulk flow vectors points in a direction similar to those found by previous measurements. At each of the three depths, the bulk flow magnitude is consistent with predictions made by the $Λ$CDM model at the 1$σ$ level. The maximum likelihood and minimum variance method were also used to analyze the 2MTF samples, giving similar results.

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Tao Hong, Christopher M. Springob, Lister Staveley-Smith, Morag I. Scrimgeour, Karen L. Masters, Lucas M. Macri, Bärbel S. Koribalski, D. Heath Jones, Tom H. Jarrett. 2014-09-01. 2MTF IV. A bulk flow measurement of the local Universe. https://doi.org/10.1093/mnras%2Fstu1774

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