TY - JOUR
T1 - EXTREMELY BRIGHT SUBMILLIMETER GALAXIES beyond the LUPUS-I STAR-FORMING REGION
AU - Tamura, Y.
AU - Kawabe, R.
AU - Shimajiri, Y.
AU - Tsukagoshi, T.
AU - Nakajima, Y.
AU - Oasa, Y.
AU - Wilner, D. J.
AU - Chandler, C. J.
AU - Saigo, K.
AU - Tomida, K.
AU - Yun, M. S.
AU - Taniguchi, A.
AU - Kohno, K.
AU - Hatsukade, B.
AU - Aretxaga, I.
AU - Austermann, J. E.
AU - Dickman, R.
AU - Ezawa, H.
AU - Goss, W. M.
AU - Hayashi, M.
AU - Hughes, D. H.
AU - Hiramatsu, M.
AU - Inutsuka, S.
AU - Ogasawara, R.
AU - Ohashi, N.
AU - Oshima, T.
AU - Scott, K. S.
AU - Wilson, G. W.
N1 - Publisher Copyright:
© 2015. The American Astronomical Society. All rights reserved.
PY - 2015/8/1
Y1 - 2015/8/1
N2 - 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.
AB - 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.
KW - ISM: individual objects (Lupus-I Molecular Cloud)
KW - galaxies: evolution
KW - galaxies: formation
KW - galaxies: high-redshift
KW - galaxies: starburst
KW - submillimeter: galaxies
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U2 - 10.1088/0004-637X/808/2/121
DO - 10.1088/0004-637X/808/2/121
M3 - Article
AN - SCOPUS:84942098870
VL - 808
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2
M1 - 121
ER -