Limits on the LyC signal from z~3 sources with secure redshift and HST coverage in the E-CDFS field
L. Guaita, L. Pentericci, A. Grazian, E. Vanzella, M. Nonino, M. Giavalisco, G. Zamorani, A. Bongiorno, P. Cassata, M. Castellano, B. Garilli, E. Gawiser, V. Le… 展开作者
L. Guaita, L. Pentericci, A. Grazian, E. Vanzella, M. Nonino, M. Giavalisco, G. Zamorani, A. Bongiorno, P. Cassata, M. Castellano, B. Garilli, E. Gawiser, V. Le Brun, O. Le Fevre, B. C. Lemaux, D. Maccagni, E. Merlin, P. Santini, L. A. M. Tasca, R. Thomas, E. Zucca, S. De Barros, N. P. Hathi, R. Amorin, S. Bardelli, A. Fontana
Aim: We aim to measure the LyC signal from a sample of sources in the Chandra deep field south. We collect star-forming galaxies (SFGs) and active galactic nuclei (AGN) with accurate spectroscopic redshifts, for which Hubble Space Telescope (HST) coverage and multi-wavelength photometry are available. Method: We selected a sample of about 200 sources at z~3. Taking advantage of HST resolution, we applied a careful cleaning procedure and rejected sources showing nearby clumps with different colours, which could be lower-z interlopers. Our clean sample consisted of 86 SFGs (including 19 narrow-band selected Lya emitters) and 8 AGN (including 6 detected in X-rays). We measured the LyC flux from aperture photometry in four narrow-band filters covering wavelengths below a 912 A rest frame (3.11<z<3.53). We estimated the ratio between ionizing (LyC flux) and 1400 A non-ionizing emissions for AGN and galaxies. Results: By running population synthesis models, we assume an average intrinsic L(1400 A)/L(900 A) ratio of 5 as the representative value for our sample. With this value and an average treatment of the lines of sight of the inter-galactic medium, we estimate the LyC escape fraction relative to the intrinsic value (fesc_rel(LyC)). We do not directly detect ionizing radiation from any individual SFG, but we are able to set a 1(2)sigma upper limit of fesc_rel(LyC)<12(24)%. This result is consistent with other non-detections published in the literature. No meaningful limits can be calculated for the sub-sample of Lya emitters. We obtain one significant direct detection for an AGN at z=3.46, with fesc_rel(LyC) = (72+/-18)%. Conclusions: Our upper limit on fescrel(LyC) implies that the SFGs studied here do not present either the physical properties or the geometric conditions suitable for efficient LyC-photon escape.
Extending Hubble into the 2030s to Resolve the Physics of LyC Escape
University of Michigan（密歇根大学）；Johns Hopkins University（约翰斯·霍普金斯大学）；Texas Christian University（得克萨斯基督教大学）；Zhejiang University（浙江大学）；University of Colorado Boulder（科罗拉多大学博尔德分校）；Stockholm University（斯德哥尔摩大学）；Space Telescope Science Institute（太空望远镜科学研究所）
New constraints on the average escape fraction of Lyman continuum radiation in z~4 galaxies from the VIMOS Ultra Deep Survey (VUDS)
确定逃离高红移星系的莱曼连续谱（LyC）光子的平均分数对于理解z>6宇宙中的再电离是如何进行的至关重要。我们希望测量来自Chandra Deep Field South（CDFS）和COSMOS领域的源样本的LyC信号，其中超深VIMOS光谱学以及多波长哈勃太空望远镜（HST）成像可用。我们从VIMOS超深巡天（VUDS）数据库中选择了46个$z\sim 4$星系的样本，使得VUDS光谱包含光谱的LyC部分，即静止帧范围$880-910Å$。利用HST成像，我们应用了仔细的清洗程序，并拒绝了所有显示附近具有不同颜色的团块的源，这些团块可能是低红移的闯入者。经过这个过程，样本减少到33个星系。我们测量所有单个源的电离通量（$895Å$处的LyC）和非电离发射（$\sim 1500 Å$处）之间的比率。我们还产生了所有源的归一化堆叠光谱。假设固有平均$L_ν(1470)/L_ν(895)$为3，我们估计个体和平均相对逃逸分数。我们没有检测到来自任何单独来源的电离辐射，虽然我们确定了一个可能的LyC发射极具有非常高的Ly $α$等效宽度（EW）。从堆叠的光谱并假设样品的平均透射率，我们测量相对逃逸分数$f_{esc}^{rel}=0.09\pm0.04$。我们还寻找LyC通量极限与源属性之间的相关性，并发现LyC通量与Ly $α$发射线EW之间的初步相关性。我们的研究结果意味着，在z $…
A Lyman continuum analysis for $\sim 100$ galaxies at $z_{\text{spec}} \sim 3$ in the Abell 2744 Cluster Field
INAF – Osservatorio Astronomico di Roma（意大利国家天体物理研究所罗马天文台）；Department of Astronomy, School of Physics, Peking University（北京大学物理学院天文学系）；Kavli Institute for Astronomy and Astrophysics, Peking University（北京大学科维理天文与天体物理研究所）；Institute of Science and Technology Austria (ISTA)（奥地利科学技术研究所）；INAF – Osservatorio Astronomico di Padova（意大利国家天体物理研究所帕多瓦天文台）；IPAC, California Institute of Technology（加州理工学院IPAC）；Dipartimento di Fisica, Università degli Studi di Milano（米兰大学物理系）；University of Ljubljana, Faculty of Mathematics and Physics（卢布尔雅那大学数学与物理学院）；Department of Physics and Astronomy, University of California Davis（加州大学戴维斯分校物理与天文学系）；Centre for Astrophysics and Supercomputing, Swinburne University of Technology（斯威本科技大学天体物理学与超级计算中心）；Space Telescope Science Institute（太空望远镜科学研究所）
Synergistic Radiative Transfer Modeling of MgII and Lyα Emission in Multiphase, Clumpy Galactic Environments: Application to Low-Redshift Lyman Continuum Leakers
LCEz4-M1: A Lyman Continuum Emitter Candidate at z = 4.444 in the MUSE Hubble Ultra Deep Field
Shanghai Astronomical Observatory, Chinese Academy of Sciences（中国科学院上海天文台）；School of Astronomy and Space Sciences, University of Chinese Academy of Sciences（中国科学院大学天文与空间科学学院）；European Southern Observatory（欧洲南方天文台）；Chinese Academy of Sciences South America Center for Astronomy, National Astronomical Observatories, CAS（中国科学院国家天文台拉美天文中心）
