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arXiv 2207.03752astro-ph.GA
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SAMI星系巡天:星系旋转与邻近星系运动之间的关系

The SAMI Galaxy Survey: The relationship between galaxy rotation and the motion of neighbours

Yifan Mai, Sam P. Vaughan, Scott M. Croom, Jesse van de Sande, Stefania Barsanti, Joss Bland-Hawthorn, Sarah Brough, Julia J. Bryant, Matthew Colless, Michael G… 展开作者

Yifan Mai, Sam P. Vaughan, Scott M. Croom, Jesse van de Sande, Stefania Barsanti, Joss Bland-Hawthorn, Sarah Brough, Julia J. Bryant, Matthew Colless, Michael Goodwin, Brent Groves, Iraklis S. Konstantopoulos, Jon S. Lawrence, Nuria P. F. Lorente, Samuel N. Richards

摘要:

利用SAMI星系巡天的数据,我们研究了1397个SAMI星系的投影恒星运动学自旋矢量与其邻近星系的视线运动之间的相关性。我们计算了SAMI星系和它们的邻居在垂直于SAMI星系角动量轴的方向上的亮度加权平均速度差。SAMI和邻居之间的亮度加权平均速度偏移,这表明SAMI星系的旋转和邻居的运动之间的相干性的信号,是9.0 $\pm$ 5.4 km s $^{-1}$(1.7 $σ$)的邻居在1 Mpc。在一个大规模的分析中,我们发现,平均速度偏移增加的邻居到2百万秒差距。然而,对于3 Mpc以外的邻居,速度与零或负值一致。在$\sim 2$ $σ$水平上,10 Mpc附近的负信号也是显著的,这表明2 Mpc以内的正信号可能来自于大尺度结构的变化。我们还计算了不同子样本的平均速度,包括不同区域的星系,不同恒星质量的星系,星系类型,$λ_{Re}$和倾角。虽然低质量、高质量、早型和低自旋星系子样本在2 Mpc内的邻星系都显示出2 - 3个$σ$相干信号,但不同倾角子样本的结果和大尺度结果表明,$\sim 2 σ$信号可能是由大尺度结构的一致散射或变化引起的。总的来说,在2百万秒差距内的邻近星系的相干信号的适度证据需要通过更大的观测和模拟研究样本来证实。

英文摘要:

Using data from the SAMI Galaxy Survey, we investigate the correlation between the projected stellar kinematic spin vector of 1397 SAMI galaxies and the line-of-sight motion of their neighbouring galaxies. We calculate the luminosity-weighted mean velocity difference between SAMI galaxies and their neighbours in the direction perpendicular to the SAMI galaxies angular momentum axes. The luminosity-weighted mean velocity offsets between SAMI and neighbours, which indicates the signal of coherence between the rotation of the SAMI galaxies and the motion of neighbours, is 9.0 $\pm$ 5.4 km s$^{-1}$ (1.7 $σ$) for neighbours within 1 Mpc. In a large-scale analysis, we find that the average velocity offsets increase for neighbours out to 2 Mpc. However, the velocities are consistent with zero or negative for neighbours outside 3 Mpc. The negative signals for neighbours at distance around 10 Mpc are also significant at $\sim 2$ $σ$ level, which indicate that the positive signals within 2 Mpc might come from the variance of large-scale structure. We also calculate average velocities of different subsamples, including galaxies in different regions of the sky, galaxies with different stellar masses, galaxy type, $λ_{Re}$ and inclination. Although low-mass, high-mass, early-type and low-spin galaxies subsamples show 2 - 3 $σ$ signal of coherence for the neighbours within 2 Mpc, the results for different inclination subsamples and large-scale results suggest that the $\sim 2 σ$ signals might result from coincidental scatter or variance of large-scale structure. Overall, the modest evidence of coherence signals for neighbouring galaxies within 2 Mpc needs to be confirmed by larger samples of observations and simulation studies.

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