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arXiv 2402.04233astro-ph.GA
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JWST揭示在1≤z≤3处盘断裂的高比例

JWST reveals a high fraction of disk breaks at $1\leq z\leq 3$

Dewang Xu, Si-Yue Yu

AI总结:

利用JWST的CEERS数据研究1≤z≤3大质量盘星系,发现II型盘断裂占56.7%,其比例和性质依赖与本地宇宙一致,并指出剧烈盘不稳定性可能是高红移盘断裂成因。

摘要:

我们分析了247个大质量、角尺度较大的盘星系的去卷积面亮度轮廓,以研究高红移盘断裂现象,使用的数据来自宇宙演化早期发布科学巡天(CEERS)的F356W波段图像,红移范围为1≤z≤3。我们发现,这些星系中有12.6%呈现I型(指数)轮廓,56.7%呈现II型(向下弯曲)轮廓,34.8%呈现III型(向上弯曲)轮廓。此外,我们表明,质量更大、中心聚集度更高或颜色更红的星系,往往表现出更少的II型断裂和更多的III型断裂。这些比例以及所探测到的对星系性质的依赖关系,与在本地宇宙中观测到的结果高度一致。特别是,在棒旋星系中,II型盘断裂半径与棒半径之比通常在2.25处达到峰值,这可能是由于棒引起的径向迁移所致。然而,长期演化所需的时间尺度可能过长,难以解释在如此高红移处观测到的断裂现象。相反,剧烈的盘不稳定性可能是其原因,其中旋臂和团块的力矩将物质向外抛掷,导致外部指数盘的形成。我们的结果为哈勃序列在这些早期时期已经确立这一论断提供了进一步证据。

英文摘要:

We analyzed the deconvolved surface brightness profiles of 247 massive and angularly large disk galaxies at $1\leq z\leq 3$ to study high-redshift disk breaks, using F356W-band images from the Cosmic Evolution Early Release Science survey (CEERS). We found that 12.6% of these galaxies exhibit type I (exponential) profiles, 56.7% exhibit type II (down-bending) profiles, and 34.8% exhibit type III (up-bending) profiles. Moreover, we showed that galaxies that are more massive, centrally concentrated, or redder, tend to show fewer type II and more type III breaks. These fractions and the detected dependencies on galaxy properties are in good agreement with those observed in the Local Universe. In particular, the ratio of the type II disk break radius to the bar radius in barred galaxies typically peaks at a value of 2.25, perhaps due to bar-induced radial migration. However, the timescale for secular evolution may be too lengthy to explain the observed breaks at such high redshifts. Instead, violent disk instabilities may be responsible, where spiral arms and clumps torque fling out the material, leading to the formation of outer exponential disks. Our results provide further evidence for the assertion that the Hubble Sequence was already in place during these early periods.

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