First systematic search for oxygen-line blobs at high redshift: Uncovering agn feedback and star formation quenching

Suraphong Yuma, Masami Ouchi, Alyssa B. Drake, Chris Simpson, Kazuhiro Shimasaku, Kimihiko Nakajima, Yoshiaki Ono, Rieko Momose, Masayuki Akiyama, Masao Mori, Masayuki Umemura

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


We present the first systematic search for extended metal-line [O II] λλ3726, 3729 nebulae, or [O II] blobs (O IIBs), at z = 1.2 using deep narrowband imaging with a survey volume of 1.9 × 105 Mpc3 on the 0.62 deg2 sky of Subaru-XMM Deep Survey (SXDS) field. We discover a giant O IIB, called "O IIB 1," with a spatial extent over ∼75 kpc at a spectroscopic redshift of z = 1.18, and also identify a total of 12 O IIBs with a size of >30 kpc. Our optical spectrum of O IIB 1 presents [Ne V] λ3426 line at the 6σ level, indicating that this object harbors an obscured type-2 active galactic nucleus (AGN). The presence of gas outflows in this object is suggested by two marginal detections of Fe II λ2587 absorption and Fe II* λ2613 emission lines both of which are blueshifted at as large as 500-600 km s-1, indicating that the heating source of O IIB 1 is AGN or associated shock excitation rather than supernovae produced by starbursts. The number density of O IIB 1-type giant blobs is estimated to be ∼5 × 10-6 Mpc-3 at z ∼ 1.2, which is comparable with that of AGNs driving outflow at a similar redshift, suggesting that giant O IIBs are produced only by AGN activity. On the other hand, the number density of small O IIBs, 6 × 10-5 Mpc-3, compared to that of z ∼ 1 galaxies in the blue cloud in the same MB range, may imply that 3% of star-forming galaxies at z ∼ 1 are quenching star formation through outflows involving extended [O II] emission.

Original languageEnglish
Article number53
JournalAstrophysical Journal
Issue number1
Publication statusPublished - 2013 Dec 10


  • galaxies: high-redshift
  • galaxy: evolution

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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