CLASH: DISCOVERY OF A BRIGHT z ≃ 6.2 DWARF GALAXY QUADRUPLY LENSED BY MACS J0329.6-0211

• Published in: Astrophysical journal. Letters 2012-03, Vol.747 (1), p.1-6
• Main Authors: Zitrin, A, Moustakas, J, Bradley, L, Coe, D, Moustakas, L A, Postman, M, Shu, X, Zheng, W, Benitez, N, Bouwens, R
• Format: Article
• Language: English
• Subjects: ASTROPHYSICS; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; Asymptotic properties; Confidence intervals; COSMIC DUST; Dwarf galaxies; ENERGY SPECTRA; GALAXIES; GALAXY CLUSTERS; GRAVITATIONAL LENSES; LYMAN LINES; MASS; NONLUMINOUS MATTER; PHOTOMETRY; RED SHIFT; RESOLUTION; Spectral energy distribution; STAR EVOLUTION; STARS; Texts; UNIVERSE
• ISSN: 2041-8205; 2041-8213
• DOI: 10.1088/2041-8205/747/1/L9

We report the discovery of a z sub(phot) = (ProQuest: Formulae and/or non-USASCII text omitted) (95% confidence level) dwarf galaxy, lensed into four images by the galaxy cluster MACS J0329.6-0211 (z sub(l) = 0.45). The galaxy is observed as a high-redshift dropout in HST/ACS/WFC3 CLASH and Spitzer/IRAC imaging. Its redshift is securely determined due to a clear detection of the Lyman break in the 18-band photometry, making this galaxy one of the highest-redshift multiply lensed objects known to date with an observed magnitude of F125W = 24.00 + or - 0.04 AB mag for its most magnified image. We also present the first strong-lensing analysis of this cluster uncovering 15 additional multiply imaged candidates of five lower-redshift sources spanning the range z sub(s) [Asymptotically = to] 2-4. The mass model independently supports the high photometric redshift and reveals magnifications of (ProQuest: Formulae and/or non-USASCII text omitted), respectively, for the four images of the high-redshift galaxy. By delensing the most magnified image we construct an image of the source with a physical resolution of ~200 pc when the universe was ~0.9 Gyr old, where the z [Asymptotically = to] 6.2 galaxy occupies a source-plane area of approximately 2.2 kpc super(2). Modeling the observed spectral energy distribution using population synthesis models, we find a demagnified stellar mass of ~10 super(9) M sub([middot in circle]), subsolar metallicity (Z/Z sub([middot in circle]) ~ 0.5), low dust content (A sub(V) ~ 0.1 mag), a demagnified star formation rate (SFR) of ~3.2 M sub([middot in circle]) yr super(-1), and a specific SFR of ~3.4 Gyr super(-1), all consistent with the properties of local dwarf galaxies.