Evidence for a dusty dark dwarf galaxy in the quadruple lens MG 0414+0534
- Faculty of Science and Engineering, Kindai University, Higashi-Osaka 577-8502 (Japan)
- Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China)
- Institute of Astronomy, Graduate School of Science, University of Tokyo, Mitaka, Tokyo 181-0015 (Japan)
- Astronomical Institute, Tohoku University, Aoba-ku, Sendai 980-8578 (Japan)
We report the 4σ detection of a faint object with a flux of ∼0.3 mJy, in the vicinity of the quadruply lensed QSO MG 0414+0534 using the Atacama Large Millimeter/submillimeter array (ALMA) Band 7. The object is most probably a dusty dark dwarf galaxy, which has not been detected in either the optical, near-infrared, or radio (centimeter) bands. An anomaly in the flux ratio of the lensed images observed in Band 7 and the mid-infrared band and the reddening of the QSO light color can be simultaneously explained if we consider the object as a lensing substructure with an ellipticity of ∼0.7 at a redshift of 0.5≲z≲1. Using the best-fit lens models with three lenses, we find that the dark matter plus baryon mass associated with the object is ∼10{sup 9} M{sub ⊙}, the dust mass is ∼10{sup 7} M{sub ⊙}, and the linear size is ≳5 kpc. Thus, our findings suggest that the object is a dusty dark dwarf galaxy. A substantial portion of faint submillimeter galaxies (SMGs) in the universe may be attributed to such dark objects.
- OSTI ID:
- 22869434
- Journal Information:
- Astrophysical Journal Letters, Vol. 835, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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