Physical Sciences and Mathematics | Open Access Articles

The Assembly Of Galaxies Over Cosmic Time, Yicheng Guo

Open Access Dissertations

To Understand how galaxies were assembled across the cosmic time remains one of the most outstanding questions in astronomy. The core of this question is how today's Hubble Sequence, namely the differentiation of galaxy morphology and its correlation to galaxy physical properties, is formed. In this thesis, we investigate the origin of the Hubble Sequence through galaxies at z~2, an epoch when the cosmic star formation activity reaches its peak and the properties of galaxies undergo dramatic transitions. Galaxies at z~2 have two important features that are distinct from nearby galaxies: much higher frequency of clumpy morphology in star-forming systems, …

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The Size-Luminosity Relation At Z=7 In Candels And Its Implication On Reionization, A. Grazian, M. Castellano, A. Fontana, L. Pentericci, J. S. Dunlop, R. J. Mclure, A. M. Koekemoer, M. E. Dickinson, S. M. Faber, H. C. Ferguson, A. Galametz, Mauro Giavalisco, N. A. Grogin, N. P. Hathi, D. D. Kocevski, K. Lai, J. A. Newman, E. Vanzella

Mauro Giavalisco

The exploration of the relation between galaxy sizes and other physical parameters has given important clues to understand the galaxy formation processes. We use the CANDELS Deep+Wide surveys in the GOODS-South, UDS and EGS fields, complemented by data from the HUDF09 program, to address the relation between size and luminosity at z\sim7. We select 153 z-band drop-out galaxies in six different fields characterized by a wide combination of depth and areal coverage, ideally suited to sample without biases the observed size-magnitude plane. Detailed simulations allow us to derive the completeness as a function of sizes and magnitudes and to quantify …

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The Source Counts Of Submillimetre Galaxies Detected At 1.1 Mm, K. S. Scott, Grant W. Wilson, I. Aretxaga, J. E. Austermann, E. L. Chapin, J. S. Dunlop, H. Ezawa, M. Halpern, B. Hatsukade, D. H. Hughes, R. Kawabe, S. Kim, K. Kohno, J. D. Lowenthal, A. Montaña, K. Nakanishi, T. Oshima, D. Sanders, D. Scott, N. Scoville, Y. Tamura, D. Welch, M. S. Yun, M. Zeballos

Grant Wilson

The source counts of galaxies discovered at sub-millimetre and millimetre wavelengths provide important information on the evolution of infrared-bright galaxies. We combine the data from six blank-field surveys carried out at 1.1 mm with AzTEC, totalling 1.6 square degrees in area with root-mean-square depths ranging from 0.4 to 1.7 mJy, and derive the strongest constraints to date on the 1.1 mm source counts at flux densities S(1100) = 1-12 mJy. Using additional data from the AzTEC Cluster Environment Survey to extend the counts to S(1100) ~ 20 mJy, we see tentative evidence for an enhancement relative to the exponential drop …

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Direct Oxygen Abundances For Low Luminosity Lvl Galaxies, Danielle A. Berg, Evan D. Skillman, Andrew R. Marble, Liese Van Zee, Charles W. Engelbracht, Janice C. Lee, Robert C. Kennicutt Jr., Daniela Calzetti, Daniel A. Dale, Benjamin D. Johnson

Daniela Calzetti

We present MMT spectroscopic observations of HII regions in 42 low luminosity galaxies in the LVL. For 31 galaxies, we measured the temperature sensitive [O III] line at a strength of 4 sigma or greater, and thus determine direct oxygen abundances. Our results provide the first direct estimates of oxygen abundance for 19 galaxies. Oxygen abundances were compared to B-band and 4.5 micron luminosities and stellar masses in order to characterize the luminosity-metallicity (L-Z) and mass-metallicity (M-Z) relationships at low-luminosity. We present and analyze a "Combined Select" sample composed of 38 objects (drawn from our parent sample and the literature) …

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Aztec Half Square Degree Survey Of The Shades Fields - Ii. Identifications, Redshifts, And Evidence For Large-Scale Structure, Michał J. Michałowski, J. S. Dunlop, R. J. Ivison, M. Cirasuolo, K. I. Caputi, I. Artexaga, V. Arumugam, J. E. Austermann, E. L. Chapin, S. C. Chapman, K. E. K. Coppin, E. Egami, D. H. Hughes, E. Ibar, A. M. J. Mortier, A. M. Schael, K. S. Scott, I. Smail, T. A. Targett, J. Wagg, Grant Wilson, L. Xu, M. Yun

Grant Wilson

The AzTEC 1.1 mm survey of the SCUBA HAlf Degree Extragalactic Survey (SHADES) fields is the largest (0.7 deg2) blank-field millimetre-wavelength survey undertaken to date at a resolution of ~18" and a depth of ~1 mJy. We have used the deep optical-to-radio multi-wavelength data in the SHADES Lockman Hole East and SXDF/UDS fields to obtain galaxy identifications for ~64% (~80% with tentative identifications) of the 148 AzTEC-SHADES 1.1 mm sources, exploiting deep radio and 24 um data complemented by methods based on 8 um flux-density and red optical-infrared (i-K) colour. This unusually high identification rate can be attributed to the …

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Full-Text Articles in Physical Sciences and Mathematics

The Assembly Of Galaxies Over Cosmic Time, Yicheng Guo

Open Access Dissertations

Mauro Giavalisco

Grant Wilson

Direct Oxygen Abundances For Low Luminosity Lvl Galaxies, Danielle A. Berg, Evan D. Skillman, Andrew R. Marble, Liese Van Zee, Charles W. Engelbracht, Janice C. Lee, Robert C. Kennicutt Jr., Daniela Calzetti, Daniel A. Dale, Benjamin D. Johnson

Daniela Calzetti

Grant Wilson