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Discovery of an Enormous Ly<i>α</i>Nebula in a Massive Galaxy Overdensity at<i>z</i>= 2.3
Cai, Zheng,Fan, Xiaohui,Yang, Yujin,Bian, Fuyan,Prochaska, J. Xavier,Zabludoff, Ann,McGreer, Ian,Zheng, Zhen-Ya,Green, Richard,Cantalupo, Sebastiano,Frye, Brenda,Hamden, Erika,Jiang, Linhua,Kashikawa, American Astronomical Society 2017 The Astrophysical journal Vol.837 No.1
<P>Enormous Ly alpha nebulae (ELANe), unique tracers of galaxy density peaks, are predicted to lie at the nodes and intersections of cosmic filamentary structures. Previous successful searches for ELANe have focused on wide-field narrowband surveys or have targeted known sources such as ultraluminous quasi-stellar objects (QSOs) or radio galaxies. Utilizing groups of coherently strong Ly alpha absorptions, we have developed a new method to identify high-redshift galaxy overdensities and have identified an extremely massive overdensity, BOSS1441, at z = 2-3. In its density peak, we discover an ELAN that is associated with a relatively faint continuum. To date, this object has the highest diffuse Ly alpha nebular luminosity of L-nebula = 5.1 +/- 0.1 x 10(44) erg s(-1). Above the 2 sigma surface brightness limit of SBLy alpha = 4.8 x 10(-18) erg s(-1) cm(-2) arcsec(-2), this nebula has an end-to-end spatial extent of 442 kpc. This radio-quiet source also has extended C IV lambda 1549 and He II lambda 1640 emission on greater than or similar to 30 kpc scales. Note that the Ly alpha, He II, and C IV emissions all have double-peaked line profiles. Each velocity component has an FWHM of approximate to 700-1000 km s(-1). We argue that this Lya nebula could be powered by shocks due to an active galactic nucleus-driven outflow or photoionization by a strongly obscured source.</P>
Cai, Zheng,Fan, Xiaohui,Bian, Fuyan,Zabludoff, Ann,Yang, Yujin,Prochaska, J. Xavier,McGreer, Ian,Zheng, Zhen-Ya,Kashikawa, Nobunari,Wang, Ran,Frye, Brenda,Green, Richard,Jiang, Linhua American Astronomical Society 2017 The Astrophysical journal Vol.839 No.2
<P>Cosmological simulations suggest a strong correlation between high optical-depth Lya absorbers, which arise from the intergalactic medium, and 3D mass overdensities on scales of 10-30 h(-1) comoving Mpc. By examining the absorption spectra of similar to 80,000 QSO sight lines over a volume of 0.1 Gpc(3) in the Sloan Digital Sky Survey III (SDSS-III), we have identified an extreme overdensity, BOSS1441, which contains a rare group of strong Lya absorbers at z = 2.32 +/- 0.02. This absorber group is associated with six QSOs at the same redshift on a 30 comoving Mpc scale. Using Mayall/MOSAIC narrowband and broadband imaging, we detect Lya emitters (LAEs) down to 0.7 x L-Ly alpha ' * a and reveal a large-scale structure of LAEs in this field. Our follow-up LBT observations have spectroscopically confirmed 20 galaxies in the density peak. We show that BOSS1441 has an LAE overdensity of 10.8 +/- 2.6 on a 15 comoving Mpc scale, which could collapse to a massive cluster with M greater than or similar to 10(15) M-circle dot at z similar to 0. This overdensity is among the most massive large-scale structures at z similar to 2 discovered to date.</P>
Wang, Feige,Wu, Xue-Bing,Fan, Xiaohui,Yang, Jinyi,Cai, Zheng,Yi, Weimin,Zuo, Wenwen,Wang, Ran,McGreer, Ian D.,Ho, Luis C.,Kim, Minjin,Yang, Qian,Bian, Fuyan,Jiang, Linhua IOP Publishing 2015 ASTROPHYSICAL JOURNAL LETTERS - Vol.807 No.1
<P>We report the discovery of an ultra-luminous quasar J030642.51+185315.8 (hereafter J0306+1853) at redshift 5.363, which hosts a supermassive black hole with M-BH = (1.07 +/- 0.27) x 10(10) M-circle dot. With an absolute magnitude M-1450 = -28.92 and a bolometric luminosity L-bol similar to 3.4 x 10(14) L-circle dot, J0306+1853 is one of the most luminous objects in the early universe. It is not likely to be a beamed source based on its small flux variability, low radio loudness, and normal broad emission lines. In addition, a z = 4.986 damped Ly alpha system (DLA) with [M/H] = -1.3 +/- 0.1, among the most metal-rich DLAs at z greater than or similar to 5, is detected in the absorption spectrum of this quasar. This ultra-luminous quasar puts strong constraints on the bright end of the quasar luminosity function and massive end of the black hole mass function. It will provide a unique laboratory for the study of BH growth and the co-evolution between a BH and the host galaxy with multi-wavelength follow-up observations. The future high-resolution spectra will give more insight into the DLA and other absorption systems along the line of sight of J0306+1853.</P>
A review of the current in-situ fouling control strategies in MBR: Biological versus physicochemical
Qiang Liu,Jiayao Ren,Yongsheng Lu,Xiaolei Zhang,Felicity A. Roddick,Linhua Fan,Yufei Wang,Huarong Yu,Ping Yao 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.98 No.-
Fouling in membrane bioreactors (MBR) is a bottleneck problem limiting their application. In-situfouling control strategies have been continuously developed for decades, and can be mainlycategorized as biological and physicochemical approaches. However, the mechanisms and performanceof these methods as well as their application prospects have not been thoroughly discussed andcompared in a systematic manner. This study was aimed at providing a detailed review on the variousin-situ biological and physicochemical methods in terms of fouling control performance, foulingreduction mechanisms and practicability. This involves a comparison of the popular biological controlstrategies including quorum quenching (QQ)) and physicochemical approaches such as NaClObackflushing, hybrid electrochemical MBR and anti-biofouling membrane development, with theanalysis of their potential, existing issues and practicality in full-scale applications. Future work is alsorecommended for developing more sustainable and more widely applicable MBR fouling controlstrategies.