EXTREMELY BRIGHT SUBMILLIMETER GALAXIES BEYOND THE LUPUS-I STAR-FORMING REGION

• Published in: The Astrophysical journal Vol. 808; no. 2; pp. 1 - 14
• Main Authors: 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., Hayashi, M., Hughes, D. H., Hiramatsu, M., Inutsuka, S., Ogasawara, R., Ohashi, N., Oshima, T., Scott, K. S., Wilson, G. W.
• Format: Journal Article
• Language: English
• Published: United Kingdom The American Astronomical Society 01.08.2015
• Subjects: Arrays; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; Asymptotic properties; ENERGY SPECTRA; Flux; FLUX DENSITY; FORECASTING; GALACTIC EVOLUTION; GALAXIES; galaxies: evolution; galaxies: formation; galaxies: high-redshift; galaxies: starburst; GRAVITATIONAL LENSES; HYDROSTATICS; ISM: individual objects (Lupus-I Molecular Cloud); LUMINOSITY; Mathematical models; PHOTOMETRY; RED SHIFT; SPECTROSCOPY; Star formation; STARS; submillimeter: galaxies
• ISSN: 0004-637X; 1538-4357; 1538-4357
• DOI: 10.1088/0004-637X/808/2/121

ABSTRACT 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 m 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 -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 mJy, combined with the other two 1.1 mm brightest sources, are deg−2, which is consistent with a model prediction that accounts for flux magnification due to strong gravitational lensing. Unexpectedly, a 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 . 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.