UNVEILING THE NATURE OF SUBMILLIMETER GALAXY SXDF 850.6

Journal Article · Wed Mar 10 00:00:00 EST 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/711/2/974· OSTI ID:21394328

Hatsukade, B; Ikarashi, S; Kohno, K ^[1]; Iono, D; Kawabe, R; Nakanishi, K; Tamura, Y ^[2]; Akiyama, T; Yoshikawa, M ^[3]; Dunlop, J S; Ivison, R J ^[4]; Peck, A B ^[5]; Biggs, A ^[6]; Ezawa, H ^[7]; Hanami, H ^[8]; Ho, P; Matsushita, S ^[9]; Hughes, D H ^[10]; Padilla, N ^[11]; Petitpas, G ^[12]

---

1. Institute of Astronomy, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan)
2. Nobeyama Radio Observatory, Minamimaki, Minamisaku, Nagano 384-1805 (Japan)
3. Astronomical Institute, Tohoku University, Aramaki, Aoba-ku, Sendai, Miyagi 980-8578 (Japan)
4. Scottish Universities Physics Alliance, Institute for Astronomy, School of Physics and Astronomy, University of Edinburgh, Royal Observatory, Edinburgh EH9 3HJ (United Kingdom)
5. Joint ALMA Observatory, Avenida El Golf 40, Piso 18, Las Condes 7550108 Santiago (Chile)
6. European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany)
7. National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)
8. Physics Section, Faculty of Humanities and Social Sciences, Iwate University, Morioka 020-8550 (Japan)
9. Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China)
10. Instituto Nacional de Astrofisica, Optica y Electronica (INAOE), Aptdo. Postal 51 y 216, 72000 Puebla, Pue. (Mexico)
11. Departamento de AstronomIa y Astrofisica, Pontificia Universidad Catolica de Chile, Vicuna Mackenna 4860, Santiago (Chile)
12. Harvard-Smithsonian Center for Astrophysics, Submillimeter Array, 645 North A'ohoku Place, Hilo, HI 96720 (United States)

We present an 880 {mu}m Submillimeter Array (SMA) detection of the submillimeter galaxy SXDF 850.6. SXDF 850.6 is a bright source (S{sub 850{sub m}}u{sub m} = 8 mJy) detected in the SCUBA Half Degree Extragalactic Survey and has multiple possible radio counterparts in its deep radio image obtained at the VLA. Our new SMA detection finds that the submillimeter emission coincides with the brightest radio emission that is found {approx}8'' north of the coordinates determined from SCUBA. Despite the lack of detectable counterparts in deep UV/optical images, we find a source at the SMA position in near-infrared and longer wavelength images. We perform spectral energy distribution (SED) model fits to UV-optical-IR photometry (u, B, V, R, i', z', J, H, K, 3.6 {mu}m, 4.5 {mu}m, 5.8 {mu}m, and 8.0 {mu}m) and to submillimeter-radio photometry (850 {mu}m, 880 {mu}m, 1100 {mu}m, and 21 cm) independently, and we find both are well described by starburst templates at a redshift of z {approx_equal} 2.2 +- 0.3. The best-fit parameters from the UV-optical-IR SED fit are a redshift of z = 1.87{sup +0.15}{sub -0.07}, a stellar mass of M{sub *} = 2.5{sup +2.2}{sub -0.3} x 10{sup 11} M{sub sun}, an extinction of A{sub V} = 3.0{sup +0.3}{sub -1.0} mag, and an age of 720{sup +1880}{sub -210} Myr. The submillimeter-radio SED fit provides a consistent redshift of z {approx} 1.8-2.5, an IR luminosity of L{sub IR} = (7-26) x10{sup 12} L{sub sun}, and a star formation rate of 1300-4500 M{sub sun} yr{sup -1}. These results suggest that SXDF 850.6 is a mature system already having a massive amount of old stellar population constructed before its submillimeter bright phase and is experiencing a dusty starburst, possibly induced by major mergers.

• OSTI ID: 21394328
• Journal Information: Astrophysical Journal, Vol. 711, Issue 2; Other Information: DOI: 10.1088/0004-637X/711/2/974; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
COSMOLOGY
EMISSION
ENERGY SPECTRA
GALACTIC EVOLUTION
GALAXIES
LUMINOSITY
MASS
PHOTOMETRY
RED SHIFT
STARS
EVOLUTION
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
SPECTRA