We studied dust reddening and [O II] emission in 1730 Mg II associated absorption systems (AAS; relative velocity with respect to QSOs, < 3000 km/s; in units of velocity of light, \b{eta}, < 0.01) with 0.4 < z_abs < 2 in the SDSS DR7, focusing on their dependence on the radio and other QSO properties. We used control samples, several with matching radio properties to show (i) AAS in radio detected (RD) QSOs cause 2.6 +/- 0.2 times higher dust extinction than those in radio undetected (RUD) ones which, in turn, cause 2.9 +/- 0.7 times the dust extinction in the intervening systems; (ii) AAS in core-dominated QSOs cause 2.0 +/- 0.1 times higher dust extinction than in lobe-dominated QSOs; (iii) occurrence of AAS is 2.1 +/- 0.2 times more likely in RD QSOs than in RUD QSOs and 1.8 +/- 0.1 time more likely in QSOs having black holes with masses larger than 1.23 x 10^{9} M_sun than in those with lower mass black holes; (iv) there is excess flux in [O II]λ3727 emission in the composite spectra of the AAS samples compared to those of the control samples, which is at the emission redshift. Presence of AAS enhances the O II emission from the AGN and/or the host galaxy. This excess is similar for both RD and RUD samples, and is 2.5 +/- 0.4 times higher in lobe-dominated compared to core-dominated samples. The excess depends on the black hole mass and Eddington ratio. All these point to the intrinsic nature of the AAS except for the systems with z_abs > z_em which could be infalling galaxies.
A Peculiar Type~II QSO Identified via Broad-band Detection of Extreme Nebular Line Emission
我们提出了S82-20,一个不寻常的红移$\approx$ 3对象中确定的SDSS条纹82宽带图像。S82-20的静止帧紫外光谱显示了来自高度电离物质的发射线,包括HeII PDMATHAMN 1640和CIV $λλ$ 1548、1550以及OVI $λλ$ 1032、1038双重峰。高的Ly $α$光度($3.5\times 10^{44}$ erg s $^{-1}$)、高的发射线等效宽度($>200$ erg s for Ly $α$)、发射线的半高宽($<800$ km s $^{-1}$)和高电离度的OVI线都支持S82-20是一个Ⅱ型类星体的解释。然而,光电离模型使用II型类星体不能完全解释测量的CIV/HeII线比,这需要一些贡献,恒星形成或高速冲击。此外,S82-20在波长超过2 $μ$ m时没有被探测到,这与发光类星体的各向同性红外发射的预期相矛盾。我们认为,S82-20是一个罕见的例子,变化的外观类星体,观察到在一个暂时的低状态,宽线区已经褪色,而窄线区仍然发射线的可能性。否则,它可能是一个罕见的情况下,一个大质量星系的生命的短期阶段,其中活跃的恒星形成和吸积到超大质量黑洞共存。
Comparing the Nebular and Stellar Dust Attenuation Curves in Nearby Star-Forming Galaxies
Korea Astronomy and Space Science Institute (KASI)(韩国天文与空间科学研究院);Department of Earth Science Education, Kyungpook National University(庆北国立大学地球科学教育系);Department of Astronomy and Space Science, Chungnam National University(忠南国立大学天文学与空间科学系);Astronomy Program, Department of Physics and Astronomy, Seoul National University(首尔国立大学物理天文学系天文学项目);SNU Astronomy Research Center, Seoul National University(首尔国立大学天文研究中心);Institute for Data Innovation in Science, Seoul National University(首尔国立大学数据创新科学研究院)
Variation of the Nebular Dust Attenuation Curve with the Properties of Local Star-forming Galaxies
我们利用SDSS DR 8巡天中位于$z\simeq 0.04-0.1$的$78,340$恒星形成星系样本,计算了星云尘埃的平均衰减曲线及其随星系物理性质的变化。利用前四条低阶巴耳末辐射线(H $α$,H $β$,H $γ$,H $δ$),得到了$0.41\,μ$ m ~ $0.66\,μ$ m范围内的星云衰减曲线,它与银河系消光曲线具有相似的形状和归一化(Milky Way curve)、最近导出的$z\sim2$典型成星星系的SMC曲线和星云衰减曲线。我们将星系划分成恒星质量,气相金属丰度和特定恒星形成率的箱,并推导出这些箱中的星云衰减曲线。这一分析表明,有非常小的变化,在形状的星云尘埃衰减曲线的属性用于bin的星系,并建议一个几乎普遍的形状的星云尘埃衰减曲线至少在星系和我们的样本中考虑的属性范围。
The AURORA Survey: Multiple Balmer and Paschen Emission Lines for Individual Star-forming Galaxies at z=1.5-4.4. II. Implications for Nebular Dust Corrections, Nebular SFRs, and Differential Reddening
University of California, Riverside(加州大学河滨分校);University of California, Los Angeles(加州大学洛杉矶分校);University of California, Davis(加州大学戴维斯分校);University of Arizona(亚利桑那大学);Max-Planck-Institut für extraterrestrische Physik(马克斯·普朗克地外物理学研究所);California Institute of Technology(加州理工学院);University College London(伦敦大学学院)
The Circumgalactic Medium of Submillimeter Galaxies. II. Unobscured QSOs within Dusty Starbursts and QSO Sightlines with Impact Parameters below 100 Kiloparsec
The JWST/AURORA Survey: Multiple Balmer and Paschen Emission Lines for Individual Star-forming Galaxies at z=1.5-4.4. I. A Diversity of Nebular Attenuation Curves and Evidence for Non-Unity Dust Covering Fractions
University of California, Riverside(加州大学河滨分校);University of California, Los Angeles(加州大学洛杉矶分校);University of Kentucky(肯塔基大学);University of Arizona(亚利桑那大学);University College London(伦敦大学学院);Niels Bohr Institute, University of Copenhagen(哥本哈根大学尼尔斯·玻尔研究所);Cosmic Dawn Center (DAWN)(宇宙黎明中心);University of Edinburgh(爱丁堡大学);Max-Planck-Institut für extraterrestrische Physik (MPE)(马克斯·普朗克地外物理研究所)
He II Emission from Wolf-Rayet Stars as a Tool for Measuring Dust Reddening
我们校准了一种测量恒星形成星系中尘埃衰减的技术。该技术利用沃尔夫-拉叶星的星风线,这是广泛观察到的星系光谱。He II 1640和4686的特征是复合线,其比例在很大程度上由原子物理学决定。因此,它们可以作为恒星尘埃探测器,就像巴耳末线被用作星云探测器一样。我们测量了银河系和大麦云云中97颗沃尔夫-拉叶星的He II 1640谱线强度。红化校正通量遵循紧密的相关性与固定的比率为7.76的He II 1640至4686线比。尘埃衰减降低了这个比率。我们提供了恒星E(B-V)和几个衰减规律的观测线比之间的关系。结合这种技术与使用的星云巴耳末衰减允许的恒星和星云尘埃衰减星系的测定,并可以探测其在不同的恒星年龄和质量制度的影响,独立于初始质量函数和恒星形成的历史。我们推导出尘埃红化的He II线通量,并将其与Balmer衰减和两个恒星形成星系中紫外线连续谱斜率的红化进行了比较。这三种方法产生的粉尘衰减在误差范围内一致。未来的应用,这种技术允许研究的恒星尘埃衰减相比,星云衰减在一个有代表性的星系样本。
Evidence for Shallow Nebular Attenuation Curves and Patchy Dust Geometry at z~2 with Pa-beta/H-alpha Measurements from JWST-MegaScience Medium Band Photometry
University of California, Berkeley(加州大学伯克利分校);University of Colorado, Boulder(科罗拉多大学博尔德分校);Leiden University(莱顿大学);Space Telescope Science Institute(太空望远镜科学研究所);The Pennsylvania State University(宾夕法尼亚州立大学);Institut d’Astrophysique de Paris, CNRS, Sorbonne Université(巴黎天体物理研究所,法国国家科学研究中心,索邦大学);University of Pittsburgh(匹兹堡大学);Niels Bohr Institute, University of Copenhagen(哥本哈根大学尼尔斯·玻尔研究所)
The Internal Nebular Attenuation Curve of Three-Dimensional Turbulent HII regions
Westlake University(西湖大学);Mount Stromlo Observatory, Australian National University(澳大利亚国立大学斯特罗洛天文台);Department of Astronomy, Boston University(波士顿大学天文学系);School of Natural Sciences, Institute for Advanced Study(普林斯顿高等研究院自然科学学院)
SDSS+JWST Census of Stellar and Nebular Dust Attenuation at $z \sim 0$-7: Mass Dependence and Redshift Evolution
University of Science and Technology of China(中国科学技术大学);The University of Tokyo(东京大学);Kavli Institute for the Physics and Mathematics of the Universe (WPI), University of Tokyo(东京大学宇宙物理数学研究 Kavli 研究所(WPI));The Graduate University for Advanced Studies, SOKENDAI(日本综合研究大学院大学);National Astronomical Observatory of Japan(日本国立天文台)
Star Formation and Nebular Attenuation from Pa$α$, Br$α$, and Br$β$ in Massive Dust-obscured Galaxies at Cosmic Noon using JWST
The University of Texas at Austin(德克萨斯大学奥斯汀分校);University of Maryland, College Park(马里兰大学帕克分校);University of Massachusetts, Amherst(马萨诸塞大学阿默斯特分校);Tufts University(塔夫茨大学);Space Telescope Science Institute(太空望远镜科学研究所);University of Arizona(亚利桑那大学);California Institute of Technology(加州理工学院)
Optical Spectroscopy of Dwarf Galaxies at $z\sim 0.15$ in the COSMOS Field: Star Formation and Dust Properties
IPAC, California Institute of Technology(加州理工学院 IPAC);The Observatories of the Carnegie Institution for Science(卡内基科学研究所天文台);Department of Physics and Astronomy, University of California, Riverside(加州大学河滨分校物理与天文学系)
Stellar Absorption Line Analysis of Local Star-Forming Galaxies: The Relation Between Stellar Mass, Metallicity, Dust Attenuation and Star Formation Rate
HYPERION. The cold ISM of rapidly growing $z>6$ quasars: diverse gas reservoirs, dust enrichment, and feedback signatures
INAF - Osservatorio Astronomico di Roma(意大利国家天体物理研究所罗马天文台);IFPU - Institute for Fundamental Physics of the Universe(宇宙基础物理研究所);INAF, Osservatorio Astronomico di Trieste(意大利国家天体物理研究所的里雅斯特天文台);INAF – Osservatorio di Astrofisica e Scienza dello Spazio di Bologna(意大利国家天体物理研究所博洛尼亚空间天体物理学与科学观测站);Scuola Normale Superiore(比萨高等师范学院)
Interpreting nebular emission lines in the high-redshift Universe
University of Sussex(苏塞克斯大学);University of Hertfordshire(赫特福德大学);University of Portsmouth(朴茨茅斯大学);Academia Sinica(中央研究院);National Astronomical Observatories, Chinese Academy of Sciences(中国科学院国家天文台);Leiden University(莱顿大学)