The ALMA REBELS survey: obscured star formation in massive Lyman-break galaxies at z = 4-8 revealed by the IRX-ß and M ? relations
The ALMA REBELS survey: obscured star formation in massive Lyman-break galaxies at z = 4-8 revealed by the IRX-ß and M ? relations
复制标题
ALMA REBELS 调查：IRX-ä 和 M 揭示了 z = 4-8 处大质量莱曼断裂星系中模糊的恒星形成？
DOI：
10.1093/mnras/stad3578
复制
发表时间：
2024
影响因子：
4.8
通讯作者：
Bowler R
中科院分区：
文献类型：
--
作者：
Bowler R
我们研究了在阿塔卡马大型毫米/亚毫米阵列（阿尔马）再电离时代亮发射线巡天（REBELS）大型计划中观测到的49个质量（log 10（M/M）> 9）Lyman-break星系（LBG）中尘埃遮蔽星星形成的程度。通过创建深堆栈的光度数据和REBELS阿尔马测量，我们确定了平均静止帧紫外（UV），光学和远红外（FIR）的属性，揭示了一个显着的分数（fobs= 0.4-0.7）的模糊星星的形成，与以前的研究一致。通过对静止坐标系UV斜率的测量，我们发现在这些红移处最亮的LBG显示出比从较暗星等处发现的颜色-星等关系外推所预期的更蓝的颜色（β <$-2.2）。在修正的红外黑体光谱能量分布（SED）下（尘埃温度为，βd= 2.0），我们发现REBELS源符合局部的“类Calzetti”星暴过剩（IRX）-β关系。通过重新分析阿尔马早期C+大型研究计划（ALPINE）中108个星系在Z_（14 -6）的观测数据，我们发现，Z_（14 -8），在静止坐标系UV中选取的大质量星系在它们的IRX-β关系中没有明显的演化。当比较从ALPINE和REBELS组合样本得到的IRX-M θ关系与在z < 4时建立的关系时，我们发现IRX中存在一个缺陷，表明在z> 4时，在给定的aM θ下，被遮蔽的星星形成的比例降低了1/3。对于具有相似恒星质量和星星形成速率的z ~（17）星系，我们的IRX-β结果与模拟和半解析模型的高红移预言符合得很好。
We investigate the degree of dust obscured star formation in 49 massive (log10(M⋆/M⊙) > 9) Lyman-break galaxies (LBGs) atz= 6.5–8 observed as part of the Atacama Large Millimeter/submillimeter Array (ALMA) Reionization Era Bright Emission Line Survey (REBELS) large program. By creating deep stacks of the photometric data and the REBELS ALMA measurements we determine the average rest-frame ultraviolet (UV), optical, and far-infrared (FIR) properties which reveal a significant fraction (fobs= 0.4–0.7) of obscured star formation, consistent with previous studies. From measurements of the rest-frame UV slope, we find that the brightest LBGs at these redshifts show bluer (β ≃ −2.2) colours than expected from an extrapolation of the colour–magnitude relation found at fainter magnitudes. Assuming a modified blackbody spectral energy distribution (SED) in the FIR (with dust temperature ofand βd= 2.0), we find that the REBELS sources are in agreement with the local ‘Calzetti-like’ starburst Infrared-excess (IRX)–β relation. By re-analysing the data available for 108 galaxies atz≃ 4–6 from the ALMA Large Program to Investigate C+ at Early Times (ALPINE) using a consistent methodology and assumed FIR SED, we show that fromz≃ 4–8, massive galaxies selected in the rest-frame UV have no appreciable evolution in their derived IRX–β relation. When comparing the IRX–M⋆relation derived from the combined ALPINE and REBELS sample to relations established atz< 4, we find a deficit in the IRX, indicating that atz> 4 the proportion of obscured star formation is lower by a factor of ≳ 3 at a given aM⋆. Our IRX–β results are in good agreement with the high-redshift predictions of simulations and semi-analytic models forz≃ 7 galaxies with similar stellar masses and star formation rates.