Discovery of an Enormous Lyα Nebula in a Massive Galaxy Overdensity at z = 2.3

Zheng Cai, Xiaohui Fan, Yujin Yang, Fuyan Bian, J. Xavier Prochaska, Ann Zabludoff, Ian McGreer, Zhen Ya Zheng, Richard Green, Sebastiano Cantalupo, Brenda Frye, Erika Hamden, Linhua Jiang, Nobunari Kashikawa, Ran Wang

Research output: Contribution to journalArticlepeer-review

112 Scopus citations


Enormous Lyα 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 Lyα absorptions, we have developed a new method to identify high-redshift galaxy overdensities and have identified an extremely massive overdensity, BOSS1441, at . In its density peak, we discover an ELAN that is associated with a relatively faint continuum. To date, this object has the highest diffuse Lyα nebular luminosity of erg s-1. Above the 2σ surface brightness limit of SB 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 and He ii emission on scales. Note that the Lyα, He ii, and C iv emissions all have double-peaked line profiles. Each velocity component has an FWHM of ≈700-1000 km s-1. We argue that this Lyα nebula could be powered by shocks due to an active galactic nucleus-driven outflow or photoionization by a strongly obscured source.

Original languageEnglish (US)
Article number71
JournalAstrophysical Journal
Issue number1
StatePublished - Mar 1 2017

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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