We present ALMA CO (2-1) detections of 24 star-forming brightest cluster galaxies (BCGs) over 0.2 < z < 1.2, constituting the largest and most distant sample of molecular gas measurements in BCGs to date. The BCGs are selected from the Spitzer Adaptation of the Red-Sequence Cluster Survey (SpARCS) to be IR-bright and therefore star-forming. We find that molecular gas is common in star-forming BCGs, detecting CO at a detection rate of 80% in our target sample of 30 objects. We additionally provide measurements of the star formation rate and stellar mass, calculated from existing MIPS 24 μm and IRAC 3.6 μm fluxes, respectively. We find these galaxies have molecular gas masses of 0.7–11.0 10¹⁰ M _⊙, comparable to other BCGs in this redshift range, and specific star formation rates that trace the main sequence of Elbaz et al. We compare our BCGs to those of the lower-redshift, cooling-flow BCG sample assembled by Edge and find that at z ≲ 0.6 the two samples show very similar correlations between their gas masses and specific SFRs. We suggest that, in this redshift regime, the ∼10% of BCGs that are star-forming process accreted molecular gas into stars through means that are agnostic to both their redshift and their cluster mass.

我们在 0.2 < z < 1.2 范围内展示了 24 个恒星形成最亮星团 (BCG) 的 ALMA CO (2-1) 检测，构成了迄今为止 BCG 中最大和最远的分子气体测量样本。BCG 是从红色序列聚类调查 (SpARCS) 的 Spitzer 改编版中选出的，具有 IR 亮度，因此可以形成恒星。我们发现分子气体在恒星形成的 BCG 中很常见，在我们的 30 个目标样本中以 80% 的检测率检测到 CO。我们还提供了恒星形成率和恒星质量的测量值，分别根据现有的 MIPS 24 μ m 和 IRAC 3.6 μ m 通量计算。我们发现这些星系的分子气体质量为 0.7-11.0 10 ¹⁰ M _⊙，与此红移范围内的其他 BCG 相当，以及追踪 Elbaz 等人的主要序列的特定恒星形成率。我们将我们的 BCG 与 Edge 组装的较低红移、冷却流 BCG 样本的 BCG 样本进行比较，发现在z ≲ 0.6 时，这两个样本的气体质量与特定恒星形成率之间显示出非常相似的相关性。我们认为，在这种红移状态下，大约 10% 的 BCG 是恒星形成过程，通过与它们的红移和星团质量无关的方式将分子气体吸积到恒星中。