Molecular gas and dust in the highly magnified z ~ 2.8 galaxy behind the Bullet Cluster
Molecular gas and dust in the highly magnified z ~ 2.8 galaxy behind the Bullet Cluster
复制标题
子弹星团后面高度放大的 z ~ 2.8 星系中的分子气体和尘埃
DOI：
10.1051/0004-6361/201117918
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发表时间：
2012
影响因子：
6.5
通讯作者：
Johansson D
中科院分区：
文献类型：
--
作者：
Johansson D
ContextThe引力放大提供了巨大的星系团，使人们有可能探测的物理条件，在遥远的星系是较低的光度比那些在空白领域和可能更有代表性的大部分高红移星系population.AimsWe的目标是约束的基本性质的分子气体在一个强烈放大submm星系位于后面的巨大的子弹星系团（1 E 0657-56）。该星系（SMM J 0658）被分成三幅图像，总放大倍数接近100。方法利用澳大利亚望远镜紧凑阵列（ATCA）对SMM J 0658的12 CO（1-0）和12 CO（3-2）谱线进行了探测。我们还使用阿塔卡马探路者实验（APEX）望远镜上的SABOCA测辐射热计相机测量了350μm处的连续谱发射。结果当将星系两个最亮图像的光谱合并时，在6.8σ和7.5σ的显著性上检测到CO（1-0）和CO（3-2）。由CO（1-0）光度，我们利用常用于亮红外星系的CO到H2的转换因子，导出冷分子气体的质量为（1.8 ± 0.3）× 109 M ~（-1）。这是恒星质量的45 ± 25%。由CO谱线的宽度，我们得到了CO发射区的动力学质量L =（1.3 ± 0.4）× 10 ~（10）（L/1 kpc）M.我们修正了SMM J 0658的红移测量，使之达到2.7793 ± 0.0003。CO（3-2）与CO（1-0）的亮温比为0.56-0.15+0.21，这与其他恒星形成星系中的值相似。用SABOCA检测到SMM J 0658在350μm处的连续发射，信噪比为3.6。该通量密度与Herschel卫星和BLAST球载望远镜先前在同一波长下的测量结果一致。我们研究了SMM J 0658的光谱能量分布，得出其尘埃温度为33 ± 5 K，尘埃质量为1.1-0.3+0.8× 107 M ~（-1）。作为亚毫米星系群的一个可能代表，它是未来观测的主要目标。
ContextThe gravitational magnification provided by massive galaxy clusters makes it possible to probe the physical conditions in distant galaxies that are of lower luminosity than those in blank fields and likely more representative of the bulk of the high-redshift galaxy population.AimsWe aim to constrain the basic properties of molecular gas in a strongly magnified submm galaxy located behind the massive Bullet Cluster (1E 0657-56). This galaxy (SMM J0658) is split into three images, with a total magnification factor of almost 100.MethodsWe used the Australia Telescope Compact Array (ATCA) to search for12CO(1–0) and12CO(3–2) line emission from SMM J0658. We also used the SABOCA bolometer camera on the Atacama Pathfinder EXperiment (APEX) telescope to measure the continuum emission at 350μm.ResultsCO(1–0) and CO(3–2) are detected at 6.8σand 7.5σsignificance when the spectra toward the two brightest images of the galaxy are combined. From the CO(1–0) luminosity we derive a mass of cold molecular gas of (1.8 ± 0.3) × 109M⊙, using the CO to H2conversion factor commonly used for luminous infrared galaxies. This is 45 ± 25% of the stellar mass. From the width of the CO lines we derive a dynamical mass within the CO-emitting regionLof (1.3 ± 0.4) × 1010(L/1 kpc)M⊙. We refine the redshift determination of SMM J0658 toz= 2.7793 ± 0.0003. The CO(3–2) to CO(1–0) brightness temperature ratio is 0.56-0.15+0.21, which is similar to the values found in other star-forming galaxies. Continuum emission at 350μm from SMM J0658 was detected with SABOCA at a signal-to-noise ratio of 3.6. The flux density is consistent with previous measurements at the same wavelength by the Herschel satellite and BLAST balloon-borne telescope. We study the spectral energy distribution of SMM J0658 and derive a dust temperature of 33 ± 5 K and a dust mass of 1.1-0.3+0.8× 107M⊙.ConclusionsSMM J0658 is one of the least massive submm galaxies discovered so far. As a likely representative of the bulk of the submm galaxy population, it is a prime target for future observations.