The VIMOS Ultra Deep Survey: The reversal of the star-formation rate − density relation at 2 z < 5
The VIMOS Ultra Deep Survey: The reversal of the star-formation rate − density relation at 2 z < 5
复制标题
VIMOS 超深巡天：2 z < 5 处恒星形成率与密度关系的逆转
DOI：
10.1051/0004-6361/202039346
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发表时间：
2022
影响因子：
6.5
通讯作者：
Bardelli, S.
中科院分区：
文献类型：
--
作者：
Lemaux, B. C.;Cucciati, O.;Le Fèvre, O.;Zamorani, G.;Lubin, L. M.;Hathi, N.;Ilbert, O.;Pelliccia, D.;Amorín, R.;Bardelli, S.
利用VIMOS超深巡天（VUDS）的光谱观测，Keck/DEIMOS的新观测，以及公开的大样本恒星形成星系的观测，我们在这里报告了早期宇宙中恒星形成速率（SFR）与星系局部环境（δgal）之间的关系（2 <z< 5）。与在较低红移（z > 2）观测到的不同，我们观测到平均SFR随着星系过密度的增加，在δgal上超过一个数量级，有一个明确的、几乎单调的增加。这一趋势的稳健性是通过计算我们测量中的不确定性和在我们的样本中代表性不足或不存在的星系群（例如，极其尘埃的恒星形成和静止的星系）来量化的，我们发现在所有情况下这一趋势仍然很重要。这种趋势似乎主要是由高密度环境中星系的增加所驱动的，这些星系的恒星质量更大，形成恒星的速度也比质量较小的星系要快。我们发现，即使在考虑了恒星质量效应之后，我们的样本中仍然存在微弱但显著的SFR -δgaltrend，这意味着额外的环境相关过程正在帮助推动这一趋势。我们还发现明确的证据表明，在密度最大的环境中，星系的平均SFR随着红移的增加而增加。这些结果为我们提供了这样一幅图景：大质量的富含气体的星系合并成atz > 3的原始星团环境，与其他星系或形成的大尺度介质相互作用，随后在这个过程中使用或失去大部分气体，并开始在红移稍低的星团中形成新生的红序列。
Utilizing spectroscopic observations taken for the VIMOS Ultra-Deep Survey (VUDS), new observations from Keck/DEIMOS, and publicly available observations of large samples of star-forming galaxies, we report here on the relationship between the star-formation rate (SFR) and the local environment (δgal) of galaxies in the early universe (2 <z< 5). Unlike what is observed at lower redshifts (z≲ 2), we observe a definite, nearly monotonic increase in the average SFR with increasing galaxy overdensity over more than an order of magnitude inδgal. The robustness of this trend is quantified by accounting for both uncertainties in our measurements and galaxy populations that are either underrepresented or not present in our sample (e.g., extremely dusty star-forming and quiescent galaxies), and we find that the trend remains significant under all circumstances. This trend appears to be primarily driven by the fractional increase of galaxies in high-density environments that are more massive in their stellar content and are forming stars at a higher rate than their less massive counterparts. We find that, even after stellar mass effects are accounted for, there remains a weak but significant SFR–δgaltrend in our sample implying that additional environmentally related processes are helping to drive this trend. We also find clear evidence that the average SFR of galaxies in the densest environments increases with increasing redshift. These results lend themselves to a picture in which massive gas-rich galaxies coalesce into proto-cluster environments atz≳ 3, interact with other galaxies or with a forming large-scale medium, subsequently using or losing most of their gas in the process, and begin to seed the nascent red sequence that is present in clusters at slightly lower redshifts.