Y. Tamura, R. Kawabe, Y. Shimajiri, T. Tsukagoshi, Y. Nakajima, Y. Oasa, D. J. Wilner, C. J. Chandler, K. Saigo, K. Tomida, M. S. Yun, A. Taniguchi, K. Kohno, B. Hatsukade, I. Aretxaga, J. E. Austermann, R. Dickman, H. Ezawa, W. M. Goss, M. HayashiD. H. Hughes, M. Hiramatsu, S. Inutsuka, R. Ogasawara, N. Ohashi, T. Oshima, K. S. Scott, G. W. Wilson

Research output: Contribution to journalArticle


We report detections of two candidate distant submillimeter galaxies (SMGs), MM J154506.4-344318 and MM J154132.7-350320, which are discovered in the AzTEC/ASTE 1.1 mm survey toward the Lupus-I star-forming region. The two objects have 1.1 mm flux densities of 43.9 and 27.1 mJy, and have Herschel/SPIRE counterparts as well. The Submillimeter Array counterpart to the former SMG is identified at 890 μm and 1.3 mm. Photometric redshift estimates using all available data from the mid-infrared to the radio suggest that the redshifts of the two SMGs are zphoto ≃ 4-5 and 3, respectively. Near-infrared objects are found very close to the SMGs and they are consistent with low-z ellipticals, suggesting that the high apparent luminosities can be attributed to gravitational magnification. The cumulative number counts at S1.1mm ≥ 25 mJy, combined with the other two 1.1 mm brightest sources, are 0.7 -0.34+0.56 deg-2, which is consistent with a model prediction that accounts for flux magnification due to strong gravitational lensing. Unexpectedly, a z > 3 SMG and a Galactic dense starless core (e.g., a first hydrostatic core) could be similar in the mid-infrared to millimeter spectral energy distributions and spatial structures at least at ≳ 1″. This indicates that it is necessary to distinguish the two possibilities by means of broadband photometry from the optical to centimeter and spectroscopy to determine the redshift, when a compact object is identified toward Galactic star-forming regions.

Original languageEnglish
Article number121
JournalAstrophysical Journal
Issue number2
Publication statusPublished - 2015 Aug 1
Externally publishedYes


  • galaxies: evolution
  • galaxies: formation
  • galaxies: high-redshift
  • galaxies: starburst
  • ISM: individual objects (Lupus-I Molecular Cloud)
  • submillimeter: galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Tamura, Y., Kawabe, R., Shimajiri, Y., Tsukagoshi, T., Nakajima, Y., Oasa, Y., Wilner, D. J., Chandler, C. J., Saigo, K., Tomida, K., Yun, M. S., Taniguchi, A., Kohno, K., Hatsukade, B., Aretxaga, I., Austermann, J. E., Dickman, R., Ezawa, H., Goss, W. M., ... Wilson, G. W. (2015). EXTREMELY BRIGHT SUBMILLIMETER GALAXIES beyond the LUPUS-I STAR-FORMING REGION. Astrophysical Journal, 808(2), [121]. https://doi.org/10.1088/0004-637X/808/2/121