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arXiv 0808.0153astro-ph
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哈勃空间望远镜到NGC 1569的新距离:星暴性质和IC 342群成员

A New Hubble Space Telescope Distance to NGC 1569: Starburst Properties and IC 342 Group Membership

Aaron J. Grocholski, Alessandra Aloisi, Roeland P. van der Marel, Jennifer Mack, Francesca Annibali, Luca Angeretti, Laura Greggio, Enrico V. Held, Donatella Ro… 展开作者

Aaron J. Grocholski, Alessandra Aloisi, Roeland P. van der Marel, Jennifer Mack, Francesca Annibali, Luca Angeretti, Laura Greggio, Enrico V. Held, Donatella Romano, Marco Sirianni, Monica Tosi

摘要:

本文介绍了距离我们最近的星暴星系之一矮不规则星系NGC 1569的深HST ACS/WFC测光。这些数据使我们能够第一次明确地探测到红巨星分支的尖端,从而确定到NGC 1569的距离。我们发现这个星系距离我们3.36 +/- 0.20 Mpc,比通常假设的距离2.2 +/- 0.6 Mpc远得多。由于其较短的距离,以前被认为是一个孤立的星系,我们的新距离坚定地将NGC 1569确定为IC 342星系群的成员。高密度的环境可能有助于解释NGC 1569的星暴性质,因为星暴通常由星系相互作用引发。另一方面,更长的距离意味着NGC 1569是一个比以前认为的更极端的星暴星系。以前估计的恒星形成率小于1 Gyr的恒星变得更强的2倍以上。比这更老的恒星不受以前研究的限制。NGC 1569的三个超级星团的动力学质量增加了约53%,达到6-7x10^5个太阳质量。

英文摘要:

We present deep HST ACS/WFC photometry of the dwarf irregular galaxy NGC 1569, one of the closest and strongest nearby starburst galaxies. These data allow us, for the first time, to unequivocally detect the tip of the red giant branch and thereby determine the distance to NGC 1569. We find that this galaxy is 3.36 +/- 0.20 Mpc away, considerably farther away than the typically assumed distance of 2.2 +/- 0.6 Mpc. Previously thought to be an isolated galaxy due to its shorter distance, our new distance firmly establishes NGC 1569 as a member of the IC 342 group of galaxies. The higher density environment may help explain the starburst nature of NGC 1569, since starbursts are often triggered by galaxy interactions. On the other hand, the longer distance implies that NGC 1569 is an even more extreme starburst galaxy than previously believed. Previous estimates of the rate of star formation for stars younger than ~ 1 Gyr become stronger by more than a factor of 2. Stars older than this were not constrained by previous studies. The dynamical masses of NGC 1569's three super star clusters, which are already known as some of the most massive ever discovered, increase by ~53% to 6-7x10^5 solar masses.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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