Galaxy Rotation Coherent with the Motions of Neighbors: Discovery of Observational Evidence

We present our discovery of observational evidence for the coherence between galaxy rotation and the average line-of-sight motion of neighbors. We use the Calar Alto Legacy Integral Field Area (CALIFA) survey data analyzed with the Python CALIFA STARLIGHT Synthesis Organizer (PyCASSO) platform, and the NASA-Sloan Atlas (NSA) catalog. After estimating the projected angular momentum vectors of 445 CALIFA galaxies, we build composite maps of their neighbor galaxies on the parameter space of line-of-sight velocity versus projected distance. The composite radial profiles of the luminosity-weighted mean velocity of neighbors show striking evidence for dynamical coherence between the rotational direction of the CALIFA galaxies and the average moving direction of their neighbor galaxies. The signal of such dynamical coherence is significant for the neighbors within 800 kpc distance from the CALIFA galaxies, for which the luminosity-weighted mean velocity is as large as 61.7+/-17.6 km/s (3.5-sigma significance to bootstrap uncertainty) when the angular momentum is measured at R_e

Keywords:

• Galaxy
• Astronomy
• observational evidence
• Physics

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