论文标题
从Alma观察到的$ Z \ $ 7.7 $ GALAXY的[O III]和[C II]的令人困惑的非检测
A puzzling non-detection of [O III] and [C II] from a $z \approx 7.7$ galaxy observed with ALMA
论文作者
论文摘要
表征早期宇宙中的星系人群是理解这些物体演变及其在宇宙电离中所起的作用的关键。但是，迄今为止，最高红移的观测数量很少。为了阐明高红移宇宙中星系的特性及其星际媒体，我们观察到lyman- $α$发射的星系Z7 \ _gsd \ _3811 $ z = 7.664 $，带有6和8的$ z = 7.664 $，带有6和8，在Atacama大型毫米/simbillimeter/simbillimeter（Alma）。我们针对远红外[O III] 88 $μm$，[C II] 158 $μm$ $ $ $发射线和尘埃连续恒星的星系Z7 \ _GSD \ _3811与Alma一起使用。我们将这些测量结果与剩下框架紫外线（UV）中的早期观察结果结合在一起，以表征对象，并将结果与观察[O III]和[C II]的早期研究的结果进行比较。 [O III] 88 $μm$和[C II] 158 $μm$排放线在Z7 \ _GSD \ _3811位置未被发现，$3σ$上限为$ 1.6 \\ \ \ \ \ \ \ \ \ \ 10^{8} {8} {8} {8} \ l _ { l _ {\ odot} $。我们没有检测到频段6或频段8中的任何灰尘连续。频段8和频段6连续体中的测量RMS分别为26和9.9 $μjy\ beam^{ - 1} $。与其他几个高红移星系相似，与局部星系相比，Z7 \ _GSD \ _3811的恒星形成速率表现出较低的[C II]发射。此外，我们对[O III]线的上限的上限低于具有相似紫外线亮度的高红移星系中所有先前观察到的[O III]线的限制。 Our ALMA band 6 and 8 dust continuum observations imply that z7\_GSD\_3811 likely has a low dust content, and our non-detections of the [O III] and [C II] lines could indicate that z7\_GSD\_3811 has a low metallicity ($Z \lesssim 0.1 \ Z_{\odot}$).
Characterizing the galaxy population in the early Universe holds the key to understanding the evolution of these objects and the role they played in cosmic reionization. However, the number of observations at the very highest redshifts are to date, few. In order to shed light on the properties of galaxies in the high-redshift Universe and their interstellar media, we observe the Lyman-$α$ emitting galaxy z7\_GSD\_3811 at $z=7.664$ with band 6 and 8 at the Atacama Large Millimeter/submillimeter Array (ALMA). We target the far-infrared [O III] 88 $μm$, [C II] 158 $μm$ emission lines and dust continuum in the star-forming galaxy z7\_GSD\_3811 with ALMA. We combine these measurements with earlier observations in the rest-frame ultraviolet (UV) in order to characterize the object, and compare results to those of earlier studies observing [O III] and [C II] emission in high-redshift galaxies. The [O III] 88 $μm$ and [C II] 158 $μm$ emission lines are undetected at the position of z7\_GSD\_3811, with $3σ$ upper limits of $1.6 \ \times \ 10^{8} \ L_{\odot}$ and $4.0 \ \times \ 10^{7} \ L_{\odot}$, respectively. We do not detect any dust continuum in band 6 nor band 8. The measured rms in the band 8 and band 6 continuum is 26 and 9.9 $μJy \ beam^{-1}$, respectively. Similar to several other high-redshift galaxies, z7\_GSD\_3811 exhibits low [C II] emission for its star formation rate compared to local galaxies. Furthermore, our upper limit on the [O III] line luminosity is lower than all the previously observed [O III] lines in high-redshift galaxies with similar ultraviolet luminosities. Our ALMA band 6 and 8 dust continuum observations imply that z7\_GSD\_3811 likely has a low dust content, and our non-detections of the [O III] and [C II] lines could indicate that z7\_GSD\_3811 has a low metallicity ($Z \lesssim 0.1 \ Z_{\odot}$).
