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

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 × 10{sup 5} Mpc{sup 3} on the 0.62 deg{sup 2} 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{sup –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{sup –6} Mpc{sup –3} at z ∼more » 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{sup –5} Mpc{sup –3}, compared to that of z ∼ 1 galaxies in the blue cloud in the same M{sub B} range, may imply that 3% of star-forming galaxies at z ∼ 1 are quenching star formation through outflows involving extended [O II] emission.« less
Authors:
; ; ;  [1] ; ;  [2] ; ;  [3] ;  [4] ; ;  [5]
  1. Institute for Cosmic Ray Research, The University of Tokyo, Kashiwa-no-ha, Kashiwa 277-8582 (Japan)
  2. Astrophysics Research Institute, Liverpool John Moores University, IC2, Liverpool Science Park, 146 Brownlow Hill, Liverpool L3 5RF (United Kingdom)
  3. Department of Astronomy, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)
  4. Astronomical Institute, Tohoku University, Aoba-ku, Sendai 980-8578 (Japan)
  5. Center for Computational Science, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan)
Publication Date:
OSTI Identifier:
22348523
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 779; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; COMPARATIVE EVALUATIONS; DENSITY; DETECTION; EMISSION; EVOLUTION; EXCITATION; FEEDBACK; GALAXIES; HEATING; METALS; OXYGEN; OXYGEN 12; QUENCHING; RED SHIFT; SPECTRA; SUPERNOVAE