Constraining dust and molecular gas properties in Lyα blobs at z ∼ 3

Yujin Yang, Roberto Decarli, Helmut Dannerbauer, Fabian Walter, Axel Weiss, Christian Leipski, Arjun Dey, Scott C. Chapman, Emeric Le Floc'H, Moire K.M. Prescott, Roberto Neri, Colin Borys, Yuichi Matsuda, Toru Yamada, Tomoki Hayashino, Christian Tapken, Karl M. Menten

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)

Abstract

In order to constrain the bolometric luminosities, dust properties, and molecular gas content of giant Lyα nebulae, the so-called Lyα blobs, we have carried out a study of dust continuum and CO line emission in two well-studied representatives of this population at z ∼ 3: an Lyα blob discovered by its strong Spitzer Multiband Infrared Photometer 24 μm detection (LABd05) and the Steidel blob 1 (SSA22-LAB01). We find that the spectral energy distribution of LABd05 is well described by an active-galactic-nucleus-starburst composite template with L FIR = (4.0 0.5) × 1012 L, comparable to high-z submillimeter galaxies and ultraluminous infrared galaxies. New Large APEX Bolometer Camera 870 μm measurements rule out the reported Submillimeter Common-User Bolometer Array detection of the SSA22-LAB01 (S 850 μm = 16.8mJy) at the >4σ level. Consistent with this, ultradeep Plateau de Bure Interferometer observations with 2″ spatial resolution also fail to detect any 1.2mm continuum source down to 0.45mJy beam-1 (3σ). Combined with the existing (sub)millimeter observations in the literature, we conclude that the FIR luminosity of SSA22-LAB01 remains uncertain. No CO line is detected in either case down to integrated flux limits of S νΔV ≲ 0.25-1.0Jykms-1, indicating a modest molecular gas reservoir, M(H2) < (1-3) × 1010M. The non-detections exclude, with high significance (12σ), the previous tentative detection of a CO J=4-3 line in the SSA22-LAB01. The increased sensitivity afforded by the Atacama Large Millimeter/submillimeter Array will be critical in studying molecular gas and dust in these interesting systems.

Original languageEnglish
Article number178
JournalAstrophysical Journal
Volume744
Issue number2
DOIs
Publication statusPublished - 2012 Jan 10

Keywords

  • galaxies: formation
  • galaxies: high-redshift
  • intergalactic medium
  • radio lines: galaxies
  • submillimeter: galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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