Browsing by Author "Lopez, Sebastian"

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    A 30 kpc Spatially Extended Clumpy and Asymmetric Galactic Outflow at z ∼ 1.7
    (2022) Shaban, Ahmed; Bordoloi, Rongmon; Chisholm, John; Sharma, Soniya; Sharon, Keren; Rigby, Jane R.; Gladders, Michael G.; Bayliss, Matthew B.; Barrientos, L. Felipe; Lopez, Sebastian; Tejos, Nicolas; Ledoux, Cedric; Florian, Michael K.
    We image the spatial extent of a cool galactic outflow with fine-structure Fe ii* emission and resonant Mg ii emission in a gravitationally lensed star-forming galaxy at z = 1.70347. The Fe ii* and Mg ii (continuum-subtracted) emissions span out to radial distances of similar to 14.33 and 26.5 kpc, respectively, with maximum spatial extents of similar to 21 kpc for Fe ii* emission and similar to 30 kpc for Mg ii emission. Mg ii emission is patchy and covers a total area of similar to 184 kpc(2), constraining the minimum area covered by the outflowing gas to be similar to 13% of the total area. Mg ii emission is asymmetric and shows similar to 21% more extended emission along the decl. direction. We constrain the covering fractions of the Fe ii* and Mg ii emission as a function of radial distance and characterize them with a power-law model. The Mg ii 2803 emission line shows two kinematically distinct emission components and may correspond to two distinct shells of outflowing gas with a velocity separation of Delta v similar to 400 km s(-1). By using multiple images with different magnifications of the galaxy in the image plane, we trace the Fe ii* and Mg ii emissions around three individual star-forming regions. In all cases, both the Fe ii* and Mg ii emissions are more spatially extended compared to the star-forming regions traced by the [O ii] emission. These findings provide robust constraints on the spatial extent of the outflowing gas and, combined with outflow velocity and column density measurements, will give stringent constraints on mass-outflow rates of the galaxy.
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    A clumpy and anisotropic galaxy halo at redshift 1 from gravitational-arc tomography
    (2018) Lopez, Sebastian; Tejos, Nicolas; Ledoux, Cedric; Barrientos L., Felipe ; Sharon, Keren; Rigby, Jane R.; Gladders, Michael D.; Bayliss, Matthew B.; Pessa, Ismael
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    A VLT/MUSE galaxy survey towards QSO Q1410: looking for a WHIM traced by BLAs in inter-cluster filaments
    (2018) Pessa, Ismael; Tejos, Nicolas; Felipe Barrientos, L.; Werk, Jessica; Bielby, Richard; Padilla, Nelson; Morris, Simon L.; Prochaska, J. Xavier; Lopez, Sebastian; Hummels, Cameron
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    Revealing the Nature of a Lyα Halo in a Strongly Lensed Interacting System at z=2.92
    (2022) Solimano, Manuel; Gonzalez-Lopez, Jorge; Aravena, Manuel; Johnston, Evelyn J.; Moya-Sierralta, Cristobal; Barrientos, Luis F.; Baylis, Matthew B.; Gladders, Michael; Infante, Leopoldo; Ledoux, Cedric; Lopez, Sebastian; Poudel, Suraj; Rigby, Jane R.; Sharon, Keren; Tejos, Nicolas
    Spatially extended halos of H i Ly alpha emission are now ubiquitously found around high-redshift star-forming galaxies. But our understanding of the nature and powering mechanisms of these halos is still hampered by the complex radiative transfer effects of the Ly alpha line and limited angular resolution. In this paper, we present resolved Multi Unit Spectroscopic Explorer (MUSE) observations of SGAS J122651.3+215220, a strongly lensed pair of L* galaxies at z = 2.92 embedded in a Ly alpha halo of L (Ly alpha ) = (6.2 +/- 1.3) x 10(42) erg s(-1). Globally, the system shows a line profile that is markedly asymmetric and redshifted, but its width and peak shift vary significantly across the halo. By fitting the spatially binned Ly alpha spectra with a collection of radiative transfer galactic wind models, we infer a mean outflow expansion velocity of approximate to 211 km s(-1), with higher values preferentially found on both sides of the system's major axis. The velocity of the outflow is validated with the blueshift of low-ionization metal absorption lines in the spectra of the central galaxies. We also identify a faint (M (1500) approximate to -16.7) companion detected in both Ly alpha and the continuum, whose properties are in agreement with a predicted population of satellite galaxies that contribute to the extended Ly alpha emission. Finally, we briefly discuss the impact of the interaction between the central galaxies on the properties of the halo and the possibility of in situ fluorescent Ly alpha production.
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    Static earth pressures on a pile supported excavation in Santiago gravel
    (2019) Lopez, Sebastian; Sanhueza, Carola; Candia, Gabriel
    Concrete soldier piles anchored in multiple levels are the most common method for supporting deep excavations in gravel. Their static design is based on limit equilibrium principles, although these procedures were originally developed for sheet piles or anchored walls on shallow excavations supporting medium-dense sand. The present study draws on the applicability of current design tools to model the static response of deep excavations in stiff gravels and their implications for design. For this purpose, the static response of an anchored pile system was evaluated with a detailed finite element model of a case study, and the results are compared with simplified hand-calculation procedures. The study unit was the 28 m deep excavation of the Beauchef Poniente building located in the fluvial deposits of the Mapocho River in Santiago. A plain strain model was developed in PLAXIS using the Hardening Soil constitutive model, with parameters determined from large-scale triaxial tests of local gravels, and the computed pile displacement were compared to actual displacement profiles measured with inclinometers. The analysis shows that the simplified procedures provide a reasonably good approximation to the computed earth pressures, internal forces on the piles, and stress in the anchors.