Revealing dust-obscured star formation in CLJ1449+0856, a cluster at z = 2
Revealing dust-obscured star formation in CLJ1449+0856, a cluster at z = 2
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DOI：
10.1093/mnras/stz1090
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发表时间：
2019-04
影响因子：
4.8
通讯作者：
Connor M A Smith;W. Gear;Matthew W. L. Smith;A. Papageorgiou;S. Eales
中科院分区：
文献类型：
--
作者：
Connor M A Smith;W. Gear;Matthew W. L. Smith;A. Papageorgiou;S. Eales
我们给出了成熟的红移2星系团CLJ1449的Scuba-2 450和850美元/亩的数据。我们结合档案赫歇尔数据来探索CLJ1449的恒星形成特性。使用高分辨率的ALMA和JVLA数据，我们确定了潜在的混乱星系，并使用贝叶斯推断工具XID+来估计它们的通量。利用光学和近红外数据和能量平衡程序Cigale，我们计算了所有星系团成员的恒星形成率和恒星质量，发现在整个3Mpc的径向范围内，恒星形成率在20-1600m$-1之间变化。中心0.5Mpc区域本身的总恒星形成率为800$\pm$200MOOT$yr$^-1}$，对应的恒星形成率密度(1.2$\pm$0.3)$\times$10$^{4}$M$_{\odot}$yr$^{-1}$Mpc$^{-3}$，大约比预期场值大五个数量级。当将该星团与红移较低的星团进行比较时，我们发现单位体积的恒星形成率向星团的中心方向增加。这表明CLJ1449的恒星形成/密度关系确实发生了逆转。基于径向恒星形成率密度分布，我们看到了恒星形成率密度升高的证据，甚至上升到3Mpc的半径。在这些半径下，高程可能比场值大一个数量级，但由于红移关联中的模糊性，无法确定确切的数字。如果是这样的话，这意味着这个星系团仍然在吸积物质，可能正在相互作用，并正在经历激烈的恒星形成。
We present SCUBA-2 450$\mu$m and 850$\mu$m data of the mature redshift 2 cluster CLJ1449. We combine this with archival Herschel data to explore the star forming properties of CLJ1449. Using high resolution ALMA and JVLA data we identify potentially confused galaxies, and use the Bayesian inference tool XID+ to estimate fluxes for them. Using archival optical and near infrared data with the energy-balance code CIGALE we calculate star formation rates, and stellar masses for all our cluster members, and find the star formation rate varies between 20-1600M$_{\odot}$yr$^{-1}$ over the entire 3Mpc radial range. The central 0.5Mpc region itself has a total star formation rate of 800$\pm$200M$_{\odot}$yr$^{-1}$, which corresponds to a star formation rate density of (1.2$\pm$0.3)$\times$10$^{4}$M$_{\odot}$yr$^{-1}$Mpc$^{-3}$, which is approximately five orders of magnitude greater than expected field values. When comparing this cluster to those at lower redshifts we find that there is an increase in star formation rate per unit volume towards the centre of the cluster. This indicates that there is indeed a reversal in the star formation/density relation in CLJ1449. Based on the radial star-formation rate density profile, we see evidence for an elevation in the star formation rate density, even out to radii of 3Mpc. At these radii the elevation could be an order of magnitude greater than field values, but the exact number cannot be determined due to ambiguity in the redshift associations. If this is the case it would imply that this cluster is still accreting material which is possibly interacting and undergoing vigorous star-formation.