Limits on the molecular gas content of z∼ 5 LBGs
Limits on the molecular gas content of z∼ 5 LBGs
复制标题
z〜5LBGs分子气体含量的限制
DOI：
--
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
M. Lehnert
中科院分区：
文献类型：
--
作者：
L. Davies;M. Bremer;E. Stanway;M. Birkinshaw;M. Lehnert
通过观测红移的CO(1-0)和CO(2-1)线发射，我们给出了莱曼破裂星系(LBGS)的分子气体含量的极限。我们观察到一个包含八个光谱确认的LBG的单场，其中七个包含在()红移范围内，第八个位于z=5.2。没有单独检测到来源。假设猛烈星暴的CO到H2的转换因子，我们对M(H2)的单个LBG的分子气体含量设定了上限。从结合所有未探测到的堆叠分析来看，典型的LBG具有与它们的恒星质量相当的H2质量极限。这一极限意味着，考虑到这些系统的恒星形成率(从它们的紫外线辐射测量)，恒星的形成最多可以维持百万年龄段，与它们的恒星种群的典型年龄相似。缺乏更大的冷气体库与LBGS是嵌入到更大的UV-暗系统中的紫外线发光超新星爆发背道而驰，因此增加了至少那些具有多个组成部分的LBGS是由合并引发的星暴的可能性。负责重新电离的来源预计将是类似于这些系统的星暴，但具有较低的光度和质量，因此恒星形成时间尺度远远短于复合时间尺度。如果是这样的话，预计在再电离时代在政府间机制中出现的电离气泡，其中心将很少有紫外线发光源。
We present limits on the molecular gas content of Lyman break galaxies (LBGs) at from observations targeting redshifted CO(1–0) and CO(2–1) line emission. We observed a single field containing eight spectroscopically confirmed LBGs, seven of which are contained within a narrow () redshift range and the eighth is at z= 5.2. No source was individually detected. Assuming the CO to H2 conversion factor for vigorous starbursts, we place upper limits on the molecular gas content of individual LBGs of M(H2) . From a stacking analysis combining all of the non-detections, the typical LBG has an H2 mass limit comparable to their stellar mass, . This limit implies that, given the star formation rates of these systems (measured from their UV emission), star formation could be sustained for at most Myr, similar to the typical ages of their stellar populations. The lack of a substantially larger reservoir of cold gas argues against the LBGs being UV-luminous superstarbursts embedded in much larger UV-dark systems and as a result increases the likelihood that at least those LBGs with multiple components are starbursts triggered by mergers. The sources responsible for re-ionization are expected to be starbursts similar to these systems, but with lower luminosities, masses and consequently with star formation time-scales far shorter than the recombination time-scale. If so, the ionized bubbles expected in the IGM during the re-ionization era will only infrequently have UV-luminous sources at their centres.
早期星系演化期间施密德塔肯尼卡特关系的偏差
DOI：
10.1088/0004-637x/717/2/1037
发表时间：
2010
期刊：
The Astrophysical Journal
影响因子：
--
作者：
Papadopoulos
通讯作者：
Papadopoulos