论文标题

在z = 0.5-1.6的星系簇中测量总紫外线:被遮盖和不可消除的恒星形成的平衡

Measuring the Total Ultraviolet Light from Galaxy Clusters at z=0.5-1.6: The Balance of Obscured and Unobscured Star-Formation

论文作者

McKinney, Jed, Ramakrishnan, Vandana, Lee, Kyoung-Soo, Pope, Alexandra, Alberts, Stacey, Chiang, Yi-Kuan, Popescu, Roxana

论文摘要

从紫外线到IR波长的组合观测对于充分说明星系簇中的恒星形成是必要的。低质量(log M/msun <10)星系通常未被检测到个体,尤其是在较高的红移(z〜1-2)的情况下,星系簇正在从托管大多数活跃的,尘埃刺激的星形星系到顽强的被动星系的快速过渡。为了说明这些未检测到的星系,我们测量了从Z = 0.5-1.6之间的Galex/nuv堆栈中出现的总光。结合Spitzer,Wise和Herschel的现有测量值,我们通过簇的远红外光谱分布(SED)研究了平均紫外线。从SED中,我们衡量了由所有集群成员星系(包括低质量种群)产生的恒星总质量以及尘埃刺激和未遮挡的恒星形成。我们在紫外线观察到的无量恒星形成的相对分数与在田间星系中观察到的相对分数。有暂定的证据表明,在z〜0.5处的恒星形成低于预期,这可能是由于其他研究报告的群集的低质量淬灭效率的快速进化而产生的。最后,Galex数据对Z <1的衍生出恒星质量比对与总光晕质量进行抗色素相处,这与Z <1的恒星质量比对,这与从集群的局部X射线观察结果中发现的趋势一致。与半分析模型中簇星形成效率的实现相比,数据显示出更陡峭的斜率。

Combined observations from UV to IR wavelengths are necessary to fully account for the star-formation in galaxy clusters. Low mass (log M/Msun<10) galaxies are typically not individualy detected, particularly at higher redshifts (z~1-2) where galaxy clusters are undergoing rapid transitions from hosting mostly active, dust-obscured star-forming galaxies to quiescent, passive galaxies. To account for these undetected galaxies, we measure the total light emerging from GALEX/NUV stacks of galaxy clusters between z=0.5-1.6. Combined with existing measurements from Spitzer, WISE, and Herschel, we study the average UV through far-infrared (IR) spectral energy distribution (SED) of clusters. From the SEDs, we measure the total stellar mass and amount of dust-obscured and unobscured star-formation arising from all cluster-member galaxies, including the low mass population. The relative fraction of unobscured star-formation we observe in the UV is consistent with what is observed in field galaxies. There is tentative evidence for lower than expected unobscured star-formation at z~0.5, which may arise from rapid redshift evolution in the low mass quenching efficiency in clusters reported by other studies. Finally, the GALEX data places strong constraints on derived stellar-to-halo mass ratios at z<1 which anti-correlate with the total halo mass, consistent with trends found from local X-ray observations of clusters. The data exhibit steeper slopes than implementations of the cluster star-formation efficiency in semi-analytical models.

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