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

Journal Article · Wed Mar 01 00:00:00 EST 2017 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/AA5D14· OSTI ID:22869257

Cai, Zheng; Prochaska, J. Xavier ^[1]; Fan, Xiaohui; Zabludoff, Ann; McGreer, Ian; Green, Richard; Frye, Brenda ^[2]; Yang, Yujin ^[3]; Bian, Fuyan ^[4]; Zheng, Zhen-Ya ^[5]; Cantalupo, Sebastiano ^[6]; Hamden, Erika ^[7]; Jiang, Linhua; Wang, Ran ^[8]; Kashikawa, Nobunari ^[9]

---

1. UCO/Lick Observatory, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States)
2. Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
3. Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong-gu Daejeon (Korea, Republic of)
4. Research School of Astronomy and Astrophysics, Mount Stromlo Observatory, Cotter Road, Weston ACT 2611 (Australia)
5. Instituto de Astrofisica, Pontificia Universidad Catolica de Chile, 7820436 Santiago (Chile)
6. Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093 Zurich (Switzerland)
7. California Institute Technology, 1200 East California Boulevard, Pasadena, CA (United States)
8. The Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China)
9. National Astronomical Observatory of Japan, Mitaka, Tokyo,181-8588 (Japan)

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 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 Lyα nebular luminosity of L{sub nebula}=5.1±0.1×10{sup 44} erg s{sup −1}. Above the 2σ surface brightness limit of SB{sub Lyα}=4.8×10{sup −18} erg s{sup −1} cm{sup −2} arcsec{sup −2}, this nebula has an end-to-end spatial extent of 442 kpc. This radio-quiet source also has extended C iv λ1549 and He ii λ1640 emission on ≳30 kpc 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{sup −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.

• OSTI ID: 22869257
• Journal Information: Astrophysical Journal, Vol. 837, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ABSORPTION
BRIGHTNESS
DENSITY
EMISSION
GALAXY NUCLEI
LUMINOSITY
LYMAN LINES
NEBULAE
PHOTOIONIZATION
RADIO GALAXIES
RED SHIFT
VELOCITY