Browsing by Author "Ellis, R. S."

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    ALMA Lensing Cluster Survey: a strongly lensed multiply imaged dusty system at z ≥ 6
    (2021) Laporte, N.; Zitrin, A.; Ellis, R. S.; Fujimoto, S.; Brammer, G.; Richard, J.; Oguri, M.; Caminha, G. B.; Kohno, K.; Yoshimura, Y.; Ao, Y.; Bauer, F. E.; Caputi, K.; Egami, E.; Espada, D.; Gonzalez-Lopez, J.; Hatsukade, B.; Knudsen, K. K.; Lee, M. M.; Magdis, G.; Ouchi, M.; Valentino, F.; Wang, T.
    We report the discovery of an intrinsically faint, quintuply-imaged, dusty galaxy MACS0600-z6 at a redshift z = 6.07 viewed through the cluster MACSJ0600.1-2008 (z = 0.46). A similar or equal to 4 sigma dust detection is seen at 1.2mm as part of the ALMA Lensing Cluster Survey (ALCS), an on-going ALMA Large programme, and the redshift is secured via [C II] 158 mu m emission described in a companion paper. In addition, spectroscopic follow-up with GMOS/Gemini-North shows a break in the galaxy's spectrum, consistent with the Lyman break at that redshift. We use a detailed mass model of the cluster and infer a magnification mu greater than or similar to 30 for the most magnified image of this galaxy, which provides an unprecedented opportunity to probe the physical properties of a sub-luminous galaxy at the end of cosmic reionization. Based on the spectral energy distribution, we infer lensing-corrected stellar and dust masses of 2.9(-2.3)(+11.5) x 10(9) and 4.8(-3.4)(+4.5) x 10(6) M-circle dot, respectively, a star formation rate of 9.7(-6.6)(+22.0) M-circle dot yr(-1), an intrinsic size of 0.54(-0.14)(+0.26) kpc, and a luminosity-weighted age of 200 +/- 100 Myr. Strikingly, the dust production rate in this relatively young galaxy appears to be larger than that observed for equivalent, lower redshift sources. We discuss if this implies that early supernovae are more efficient dust producers and the consequences for using dust mass as a probe of earlier star formation.
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    DETECTION OF THREE GAMMA-RAY BURST HOST GALAXIES AT z similar to 6
    (IOP PUBLISHING LTD, 2016) McGuire, J. T. W.; Tanvir, N. R.; Levan, A. J.; Trenti, M.; Stanway, E. R.; Shull, J. M.; Wiersema, K.; Perley, D. A.; Starling, R. L. C.; Bremer, M.; Stocke, J. T.; Hjorth, J.; Rhoads, J. E.; Curtis Lake, E.; Schulze, S.; Levesque, E. M.; Robertson, B.; Fynbo, J. P. U.; Ellis, R. S.; Fruchter, A. S.
    Long-duration gamma-ray bursts (GRBs) allow us to pinpoint and study star-forming galaxies in the early universe, thanks to their orders of magnitude brighter peak luminosities compared to other astrophysical sources, and their association with the deaths of massive stars. We present Hubble Space Telescope Wide Field Camera 3 detections of three Swift GRB host galaxies lying at redshifts z = 5.913 (GRB 130606A), z = 6.295 (GRB 050904), and z = 6.327 (GRB 140515A) in the F140W (wide-JH band, lambda(obs) similar to 1.4 mu m) filter. The hosts have magnitudes (corrected for Galactic extinction) of m(lambda obs) = 26.34(-0.16)(+0.14), 27.56(-0.22)(+0.18), and 28.30(-0.33)(+0.25) respectively. In all three cases, the probability of chance coincidence of lower redshift galaxies is less than or similar to 2%, indicating that the detected galaxies are most likely the GRB hosts. These are the first detections of high-redshift (z > 5) GRB host galaxies in emission. The galaxies have luminosities in the range 0.1-0.6 L-z=6* (with M-1600* = -20.95 +/- 0.12) and half-light radii in the range 0.6-0.9 kpc. Both their half-light radii and luminosities are consistent with existing samples of Lyman-break galaxies at z similar to 6. Spectroscopic analysis of the GRB afterglows indicate low metallicities ([M/H] less than or similar to -1) and low dust extinction (AV less than or similar to 0.1) along the line of sight. Using stellar population synthesis models, we explore the implications of each galaxy's luminosity for its possible star-formation history and consider the potential for emission line metallicity determination with the upcoming James Webb Space Telescope.
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    The absence of [C II] 158 mu m emission in spectroscopically confirmed galaxies at z > 8
    (2019) Laporte, Nicolás; Katz, H.; Ellis, R. S.; Lagache, G.; Bauer, Franz Erik; Boone, F.; Inoue, A. K.; Hashimoto, T.; Matsuo, H.; Mawatari, K.; Tamura, Y.