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arXiv 2306.04035astro-ph.GA
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WALLABY先导巡天:近邻星系中HI结构参数的多样性

WALLABY Pilot Survey: The diversity of HI structural parameters in nearby galaxies

T. N. Reynolds, B. Catinella, L. Cortese, N. Deg, H. Denes, A. Elagali, B. -Q. For, P. Kamphuis, D. Kleiner, B. S. Koribalski, K. Lee-Waddell, C. Murugeshan, W.… 展开作者

T. N. Reynolds, B. Catinella, L. Cortese, N. Deg, H. Denes, A. Elagali, B. -Q. For, P. Kamphuis, D. Kleiner, B. S. Koribalski, K. Lee-Waddell, C. Murugeshan, W. Raja, J. Rhee, K. Spekkens, L. Staveley-Smith, J. M. van der Hulst, J. Wang, T. Westmeier, O. I. Wong, F. Bigiel, A. Bosma, B. W. Holwerda, D. A. Leahy, M. J. Meyer

AI总结:

本研究利用WALLABY巡天数据,结合多波段光度测量,分析了约280个近邻星系的HI气体盘结构参数,发现HI结构参数与恒星质量、面密度呈负相关,与恒星形成呈正相关,并揭示了不同归一化方法对相关性的影响。

摘要:

我们研究了由Widefield ASKAP L-band Legacy All-sky Blind Survey(WALLABY,宽视场ASKAP L波段遗留全天盲巡天)探测到的约280个近邻星系中性原子氢(HI)气体盘的尺寸和平均面密度的多样性。我们将Hydra星系团和NGC 4636群场先导观测中均匀观测的干涉测量HI数据,与从紫外、光学和近红外成像巡天测得的光度测量相结合,以研究恒星结构、恒星形成与HI结构参数之间的相互作用。我们通过HI盘相对于光学盘的尺寸以及使用有效半径和等密度半径测量的平均HI面密度来量化HI结构。对于分辨率大于1.3个波束的星系,我们发现具有更高恒星质量和恒星面密度的星系往往具有不那么延展的HI盘和更低的HI面密度:等密度HI结构参数对恒星质量和恒星质量面密度显示出微弱的负依赖性。当我们将样本限制在分辨率大于2个波束的星系时,这些趋势得到增强。我们发现具有更高HI面密度和更延展HI盘的星系往往具有更强的恒星形成:等密度HI结构参数与恒星形成具有更强的相关性。用光学有效半径(而非等光半径)对HI盘尺寸进行归一化,会产生与恒星质量和恒星面密度的正相关性,并消除与恒星形成的相关性。这是因为有效和等密度HI半径以相似的速率随质量增加,而在光学上,有效半径的增加速度慢于等光半径。我们的结果表明,借助WALLABY,我们能够开始弥合具有高空间分辨率HI数据的小星系样本与使用空间上未分辨的单天线数据的大型统计研究之间的差距。

英文摘要:

We investigate the diversity in the sizes and average surface densities of the neutral atomic hydrogen (HI) gas discs in ~280 nearby galaxies detected by the Widefield ASKAP L-band Legacy All-sky Blind Survey (WALLABY). We combine the uniformly observed, interferometric HI data from pilot observations of the Hydra cluster and NGC 4636 group fields with photometry measured from ultraviolet, optical and near-infrared imaging surveys to investigate the interplay between stellar structure, star formation and HI structural parameters. We quantify the HI structure by the size of the HI relative to the optical disc and the average HI surface density measured using effective and isodensity radii. For galaxies resolved by >1.3 beams, we find that galaxies with higher stellar masses and stellar surface densities tend to have less extended HI discs and lower HI surface densities: the isodensity HI structural parameters show a weak negative dependence on stellar mass and stellar mass surface density. These trends strengthen when we limit our sample to galaxies resolved by >2 beams. We find that galaxies with higher HI surface densities and more extended HI discs tend to be more star forming: the isodensity HI structural parameters have stronger correlations with star formation. Normalising the HI disc size by the optical effective radius (instead of the isophotal radius) produces positive correlations with stellar masses and stellar surface densities and removes the correlations with star formation. This is due to the effective and isodensity HI radii increasing with mass at similar rates while, in the optical, the effective radius increases slower than the isophotal radius. Our results demonstrate that with WALLABY we can begin to bridge the gap between small galaxy samples with high spatial resolution HI data and large, statistical studies using spatially unresolved, single-dish data.

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