PACS-Herschel FIR detections of Lyman-alpha emitters at 2.0<z<3.5
I. Oteo, A. Bongiovanni, A. M. Pérez García, J. Cepa, A. Ederoclite, M. Sánchez-Portal, I. Pintos-Castro, R. Pérez-Martínez, B. Altieri, P. Andreani, H. Aussel,… 展开作者
I. Oteo, A. Bongiovanni, A. M. Pérez García, J. Cepa, A. Ederoclite, M. Sánchez-Portal, I. Pintos-Castro, R. Pérez-Martínez, B. Altieri, P. Andreani, H. Aussel, S. Berta, A. Cimatti, E. Daddi, D. Elbaz, N. Förster Schreiber, R. Genzel, D. Lutz, B. Magnelli, R. Maiolino, A. Poglitsch, P. Popesso, F. Pozzi, E. Sturm, L. Tacconi, I. Valtchanov
在这项工作中，我们分析了56个光谱选择的恒星形成（SF）的Ly $α$发射星系在2.0 $\lesssim$ z $\lesssim$ 3.5使用光谱能量分布（SED）拟合程序从静止帧紫外到中红外和直接160 $μ$ m的观测与光电探测器阵列相机和光谱仪（PACS）仪器板载\emph{Herschel Space Observatory}的物理性质。我们将LAEs定义为静止坐标系Ly $α$等效宽度（Ly $α$ EW $_{rest-frame}$）大于20 μ m（窄带搜索的典型阈值）的Ly $α$发射星系。Ly $α$发射星系与Ly $α$ EW $_{rest-frame}$被称为非LAEs。作为对每个物体进行单独SED拟合的结果，我们发现所研究的LAE样本包含年龄大多低于1亿年的星系以及各种各样的尘埃衰减、SFR和恒星质量。物理性质的不均匀性也表现在形态上，从膨胀状星系到高度聚集的星系。以这种方式，我们发现，LAE在2.0 $\lesssim$ z $\lesssim$ 3.5是非常多样化的，并不具有双峰性质，如在以前的作品中所建议的。此外，LAEs和非LAEs之间的主要区别是它们的尘埃衰减，因为LAEs不像非LAEs那样充满尘埃。在FIR一侧，样本中的四个星系（两个LAE和两个非LAE）具有PACS-FIR对应物。它们的总红外光度都在ULIRG范围内，都是尘埃天体，A $_{1200}$ $\gtrsim$ 4等。这是来自直接FIR测量的指示，即灰尘和Ly $α$发射不是相互排斥的。在z $\sim$ 0.3处看不到这种红色尘埃LAEs，这表明通过Ly $α$发射选择的星系的红外性质具有红移。
英文摘要：
In this work we analyze the physical properties of a sample of 56 spectroscopically selected star-forming (SF) Ly$α$ emitting galaxies at 2.0$\lesssim$z$\lesssim$3.5 using both a spectral energy distribution (SED) fitting procedure from rest-frame UV to mid-IR and direct 160$μ$m observations taken with the Photodetector Array Camera & Spectrometer (PACS) instrument onboard \emph{Herschel Space Observatory}. We define LAEs as those Ly$α$ emitting galaxies whose rest-frame Ly$α$ equivalent widths (Ly$α$ EW$_{rest-frame}$) are above 20Å, the typical threshold in narrow-band searches. Ly$α$ emitting galaxies with Ly$α$ EW$_{rest-frame}$ are called non-LAEs. As a result of an individual SED fitting for each object, we find that the studied sample of LAEs contains galaxies with ages mostly below 100Myr and a wide variety of dust attenuations, SFRs, and stellar masses. The heterogeneity in the physical properties is also seen in the morphology, ranging from bulge-like galaxies to highly clumpy systems. In this way, we find that LAEs at 2.0$\lesssim$z$\lesssim$3.5 are very diverse, and do not have a bimodal nature, as suggested in previous works. Furthermore, the main difference between LAEs and non-LAEs is their dust attenuation, because LAEs are not as dusty as non-LAEs. On the FIR side, four galaxies of the sample (two LAEs and two non-LAEs) have PACS-FIR counterparts. Their total IR luminosity place all of them in the ULIRG regime and are all dusty objects, with A$_{1200}$$\gtrsim$4mag. This is an indication from direct FIR measurements that dust and Ly$α$ emission are not mutually exclusive. This population of red and dusty LAEs is not seen at z$\sim$0.3, suggesting an evolution with redshift of the IR nature of galaxies selected via their Ly$α$ emission.
Physical properties of Herschel selected galaxies in a semi-analytic galaxy formation model
[摘要]我们利用半解析宇宙学模型，其中包括尘埃衰减和发射的简单处方，以预测最近发射的赫歇尔空间天文台在诸如GOODS-Herschel的深场中可能探测到的星系的可观测和物理特性。我们比较了我们的预测差分星系数计数在PACS（100和160）和SPIRE（250，350和500微米）波段与现有的观测。我们发现非常好的协议与PACS波段的计数，整体计数和星系的红移在z < 2. At z >2我们的模型低估了明亮的星系的数量的一个因素的10。对于所有三个SPIRE波段，一致性要差得多，并且随着波长的增加而逐渐变差。我们讨论了一些可能的原因，这些差异，并假设观测通量估计的混合效果可能是占主导地位的问题。我们注意到，PACS数量计数是相对稳健的粉尘排放模板的变化，而预测的SPIRE数量计数更多的模板依赖。我们提出了定量预测所观察到的PACS 160和SPIRE 250微米通量和物理量，如晕质量，恒星质量，冷气质量，恒星形成率，和总红外（IR）光度之间的关系，在不同的红移。我们还提出了定量预测PACS 160微米的流量和星系经历了最近的主要或次要合并的概率之间的相关性。虽然我们的模型预测这些量之间有很强的相关性，使得更多的红外发光星系更有可能是合并驱动的，我们发现，超过一半的所有高红移红外发光星系检测到的赫歇尔能够达到他们的高恒星形成率没有增强合并。
Far-Infrared Line Imaging of the Starburst Ring in NGC 1097 with the Herschel/PACS Spectrometer
NGC 1097是一个邻近的SBb星系，有一个塞弗特核和一个明亮的星暴环。我们研究的星际介质（ISM）的物理特性，在环使用空间分辨远红外光谱图的环核星暴环的NGC 1097，获得与PACS光谱仪上的赫歇尔太空望远镜。特别地，我们绘制了[OI] 63 $μ$ m、[OIII] 88 $μ$ m、[NII] 122 $μ$ m、[CII] 158 $μ$ m和[NII] 205 $μ$ m的重要ISM冷却和诊断发射线。我们观察到，在[OI] 63 $μ$ m，[OIII] 88 $μ$ m，和[NII] 122 $μ$ m的线图中，发射沿环的NE部分成簇增强。我们观察到环核环快速旋转的证据，旋转速度约为220 $ km s$ ^{-1} $ (inclination uncorrected) measured in all lines. The [OI] 63 $ μ $m/[CII] 158 $ μ $m ratio varies smoothly throughout the central region, and is enhanced on the northeastern part of the ring, which may indicate a stronger radiation field. This enhancement coincides with peaks …
Herschel/PACS spectroscopy of NGC 4418 and Arp 220: H2O, H2^{18}O, OH, ^{18}OH, O I, HCN and NH3
Herschel/PACS spectroscopy of the luminous infrared galaxies NGC4418 and Arp220 reveals high excitation in H2O, OH, HCN, and NH3. In NGC4418, absorption lines were detected with E_low>800 K (H2O), 600 K (OH), 1075 K (HCN), and 600 K (NH3), while in Arp220 the excitation is somewhat lower. While outflow signatures in moderate excitation lines are seen in Arp220 as reported in previous studies, in NGC4418 the lines tracing its outer regions are redshifted relative to the nucleus, suggesting an inflow with Mdot<~12 Msun yr^{-1}. Both galaxies have warm (Tdust>~100 K) nuclear continuum components,…
