Browsing by Author "Moustakas, J."

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    A GEOMETRICALLY SUPPORTED z similar to 10 CANDIDATE MULTIPLY IMAGED BY THE HUBBLE FRONTIER FIELDS CLUSTER A2744
    (2014) Zitrin, A.; Zheng, W.; Broadhurst, T.; Moustakas, J.; Lam, D.; Shu, X.; Huang, X.; Diego J. M.; Bauer, Franz Erik; Infante Lira, Leopoldo
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    CLASH: THE ENHANCED LENSING EFFICIENCY OF THE HIGHLY ELONGATED MERGING CLUSTER MACS J0416.1-2403
    (2013) Zitrin, A.; Meneghetti, M.; Umetsu, K.; Broadhurst, T.; Bartelmann, M.; Bouwens, R.; Bradley, L.; Carrasco, M.; Coe, D.; Ford, H.; Kelson, D.; Koekemoer, A. M.; Medezinski, E.; Moustakas, J.; Moustakas, L. A.; Nonino, M.; Postman, M.; Rosati, P.; Seidel, G.; Seitz, S.; Sendra, I.; Shu, X.; Vega, J.; Zheng, W.
    We perform a strong lensing analysis of the merging galaxy cluster MACS J0416.1-2403 (M0416; z = 0.42) in recent CLASH/HST observations. We identify 70 new multiple images and candidates of 23 background sources in the range 0.7 less than or similar to z(phot) less than or similar to 6.14 including two probable high-redshift dropouts, revealing a highly elongated lens with axis ratio similar or equal to 5:1, and a major axis of similar to 100 '' (z(s) similar to 2). Compared to other well-studied clusters, M0416 shows an enhanced lensing efficiency. Although the critical area is not particularly large (similar or equal to 0.6 square'; z(s) similar to 2), the number of multiple images, per critical area, is anomalously high. We calculate that the observed elongation boosts the number of multiple images, per critical area, by a factor of similar to 2.5x, due to the increased ratio of the caustic area relative to the critical area. Additionally, we find that the observed separation between the two main mass components enlarges the critical area by a factor of similar to 2. These geometrical effects can account for the high number (density) of multiple images observed. We find in numerical simulations that only similar to 4% of the clusters (with M-vir >= 6 x 10(14) h(-1) M-circle dot) exhibit critical curves as elongated as in M0416.
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    Evolution of Balmer jump selected galaxies in the ALHAMBRA survey
    (2016) Iribarren, P.; Infante Lira, Leopoldo; Padilla, Nelson; Lacerna Zambrano, Iván Andrés; Garcia, S.; Orsi, A.; Arancibia, A.; Moustakas, J.; Cristobal, D.; Moles, M.; Fernandez, A.; Martinez, V.; Cervino, M.; Alfaro, E.; Ascaso, B.; Arnalte, P.; Nieves, L.; Benitez, N.
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    Metallicity effects on dust properties in starbursting galaxies
    (2008) Engelbracht, C. W.; Rieke, G. H.; Gordon, K. D.; Smith, J. -D. T.; Werner, M. W.; Moustakas, J.; Willmer, C. N. A.; Vanzi, L.
    We present infrared observations of 66 starburst galaxies over the full range of oxygen abundances observed in local star-forming galaxies, from 12 + log(O/H) = 7.1 to 8.9. The data include imaging and spectroscopy from the Spitzer Space Telescope, supplemented by ground-based near-infrared imaging. We confirm a strong correlation of aromatic emission with metallicity, with a threshold at 12 + log(O/H) similar to 8. We show that the far-infrared color temperature of the large dust grains increases toward lower metallicity, peaking at a metallicity of 8 before turning over. We compute dust masses and compare them to H I masses from the literature to derive the ratio of atomic gas to dust, which increases by nearly 3 orders of magnitude between solar metallicity and a metallicity of 8, below which it flattens out. The abrupt change in aromatic emission at mid-infrared wavelengths thus appears to be reflected in the far-infrared properties, indicating that metallicity changes affect the composition of the full range of dust grain sizes that dominate the infrared emission. Although the great majority of galaxies show similar patterns of behavior as described above, there are three exceptions, SBS 0335-052E, Haro 11, and SHOC 391. Their infrared SEDs are dominated energetically by the mid-IR near 24 mu m rather than by the 60-200 mu m region. In addition, they have very weak near-infrared outputs and their SEDs are dominated by emission by dust at wavelengths as short as 1.8 mu m. The latter behavior indicates that the dominant star-forming episodes in them are extremely young. The component of the ISM responsible for the usual far-infrared emission appears to be either missing or inefficiently heated in these three galaxies.
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    YOUNG GALAXY CANDIDATES IN THE HUBBLE FRONTIER FIELDS. III. MACS J0717.5+3745
    (2016) Laporte, Nicolás; Infante Lira, Leopoldo; Troncoso Iribarren, P.; Zheng, W.; Molino, A.; Bauer, Franz Erik; Bina, D.; Broadhurst, Tom; Chilingarian, I.; Huang, X.; García, S.; Kim, S.; Marques Chaves, R.; Moustakas, J.; Pelló, R.; Pérez Fournon, I.; Shu, X.; Streblyanska, A.; Zitrin, A.