Discovery of a Giant Lya Emitter Near the Reionization Epoch

We report the discovery of a giant Lya emitter (LAE) with a Spitzer/IRAC counterpart near the reionization epoch at z=6.595. The giant LAE is found from the extensive 1 deg^2 Subaru narrow-band survey for z=6.6 LAEs in the Subaru/XMM-Newton Deep Survey (SXDS) field, and subsequently identified by de...

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Bibliographic Details
Published in:arXiv.org 2009-02
Main Authors: Ouchi, Masami, Ono, Yoshiaki, Egami, Eiichi, Saito, Tomoki, Oguri, Masamune, McCarthy, Patrick J, Duncan, Farrah, Kashikawa, Nobunari, Momcheva, Ivelina, Shimasaku, Kazuhiro, Nakanishi, Kouichiro, Furusawa, Hisanori, Akiyama, Masayuki, Dunlop, James S, Mortier, Angela M J, Okamura, Sadanori, Hayashi, Masao, Cirasuolo, Michele, Dressler, Alan, Iye, Masanori, Jarvis, Matt J, Kodama, Tadayuki, Martin, Crystal L, McLure, Ross J, Ohta, Kouji, Yamada, Toru, Yoshida, Michitoshi
Format: Article
Language:English
Subjects:
Deimos
Deposition
Emitters
Galaxies
Infrared imagery
Ionization
Nebulae
Outflow
Star & galaxy formation
Star formation
Stellar mass
XMM (spacecraft)
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Summary:We report the discovery of a giant Lya emitter (LAE) with a Spitzer/IRAC counterpart near the reionization epoch at z=6.595. The giant LAE is found from the extensive 1 deg^2 Subaru narrow-band survey for z=6.6 LAEs in the Subaru/XMM-Newton Deep Survey (SXDS) field, and subsequently identified by deep spectroscopy of Keck/DEIMOS and Magellan/IMACS. Among our 207 LAE candidates, this LAE is not only the brightest narrow-band object with L(Lya) = 3.9+/-0.2 x 10^43 erg/s in our survey volume of 10^6 Mpc^3, but also a spatially extended Lya nebula with the largest isophotal area whose major axis is at least ~3''. This object is more likely to be a large Lya nebula with a size of >~17 kpc than to be a strongly-lensed galaxy by a foreground object. Our Keck spectrum with medium-high spectral and spatial resolutions suggests that the velocity width is v(FWHM)=251+/-21 km/s, and that the line-center velocity changes by ~60 km/s in a 10-kpc range. The stellar mass and star-formation rate are estimated to be 0.9-5.0 x 10^10 Mo and >34 Mo/yr, respectively, from the combination of deep optical to infrared images of Subaru, UKIDSS-Ultra Deep Survey, and Spitzer/IRAC. Although the nature of this object is not yet clearly understood, this could be an important object for studying cooling clouds accreting onto a massive halo, or forming-massive galaxies with significant outflows contributing to cosmic reionization and metal enrichment of inter-galactic medium.
ISSN:2331-8422
DOI:10.48550/arxiv.0807.4174