The Formation and Evolution of S0 Galaxies

This thesis studies the origin of local S0 galaxies and their possible links to other morphological types. To address these issues, two different approaches have been adopted: a detailed study of the stellar populations of S0s in the Fornax Cluster and a study of the Tully-Fisher Relation (TFR) of local S0s in different environments. The analysis of the central absorption line indices of 9 S0 galaxies in the Fornax Cluster indicates that they correlate with central velocity dispersions (sigma0). However, the stellar population properties of these S0s indicates that the observed trends seem to be produced by relative differences in age and alpha-element abundances and not in metallicity as previous studies have found in ellipticals. The observed scatter in the line indices versus sigma0 relations can be partially explained by the rotationally-supported nature of many of these systems. It was also confirmed that the dynamical mass is the driving physical property of all these correlations and in our Fornax S0s it has to be estimated assuming rotational support. A study of the local B- and Ks-band TFR in S0 galaxies shows that these objects lie systematically below the TFR for nearby spirals in both the optical and infrared bands. This offset can be crudely interpreted as arising from the luminosity evolution of spiral galaxies that have faded since ceasing star formation. However, a large scatter is also found in the S0 TFR, which means that these galaxies cannot have formed exclusively by this simple fading mechanism after all transforming at a single epoch. For the Fornax Cluster data, the offset from the TFR correlates with the estimated age of the stars in the centre of individual galaxies implying that part of the scatter in the S0 TFR arises from the different times at which galaxies began their transformation

The Formation and Evolution of S0 Galaxies

This thesis studies the origin of local S0 galaxies and their possible links to other morphological types. To address these issues, two different approaches have been adopted: a detailed study of the stellar populations of S0s in the Fornax Cluster and a study of the Tully-Fisher Relation (TFR) of local S0s in different environments. The analysis of the central absorption line indices of 9 S0 galaxies in the Fornax Cluster indicates that they correlate with central velocity dispersions (sigma0). However, the stellar population properties of these S0s indicates that the observed trends seem to be produced by relative differences in age and alpha-element abundances and not in metallicity as previous studies have found in ellipticals. The observed scatter in the line indices versus sigma0 relations can be partially explained by the rotationally-supported nature of many of these systems. It was also confirmed that the dynamical mass is the driving physical property of all these correlations and in our Fornax S0s it has to be estimated assuming rotational support. A study of the local B- and Ks-band TFR in S0 galaxies shows that these objects lie systematically below the TFR for nearby spirals in both the optical and infrared bands. This offset can be crudely interpreted as arising from the luminosity evolution of spiral galaxies that have faded since ceasing star formation. However, a large scatter is also found in the S0 TFR, which means that these galaxies cannot have formed exclusively by this simple fading mechanism after all transforming at a single epoch. For the Fornax Cluster data, the offset from the TFR correlates with the estimated age of the stars in the centre of individual galaxies implying that part of the scatter in the S0 TFR arises from the different times at which galaxies began their transformation

Predicting Future Space Near-IR Grism Surveys using the WFC3 Infrared Spectroscopic Parallels Survey

We present near-infrared emission line counts and luminosity functions from the HST WFC3 Infrared Spectroscopic Parallels (WISP) program for 29 fields (0.037 deg^2) observed using both the G102 and G141 grisms. Altogether we identify 1048 emission line galaxies with observed equivalent widths greater than 40 Angstroms, 467 of which have multiple detected emission lines. The WISP survey is sensitive to fainter flux levels (3-5x10^-17 ergs/s/cm^2) than the future space near-infrared grism missions aimed at baryonic acoustic oscillation cosmology (1-4x10^-16 ergs/s/cm^2), allowing us to probe the fainter emission line galaxies that the shallower future surveys may miss. Cumulative number counts of 0.7<z<1.5 galaxies reach 10,000 deg^-2 above an H-alpha flux of 2x10^-16 ergs/s/cm^2. H-alpha-emitting galaxies with comparable [OIII] flux are roughly 5 times less common than galaxies with just H-alpha emission at those flux levels. Galaxies with low H-alpha/[OIII] ratios are very rare at the brighter fluxes that future near-infrared grism surveys will probe; our survey finds no galaxies with H-alpha/[OIII] < 0.95 that have H-alpha flux greater than 3x10^-16 ergs/s/cm^2. Our H-alpha luminosity function contains a comparable number density of faint line emitters to that found by the NICMOS near-infrared grism surveys, but significantly fewer (factors of 3-4 less) high luminosity emitters. We also find that our high redshift (z=0.9-1.5) counts are in agreement with the high redshift (z=1.47) narrow band H-alpha survey of HiZELS (Sobral et al. 2013), while our lower redshift luminosity function (z=0.3-0.9) falls slightly below their z=0.84 result. The evolution in both the H-alpha luminosity function from z=0.3--1.5 and the [OIII] luminosity function from z=0.7-2.3 is almost entirely in the L* parameter, which steadily increases with redshift over those ranges.Comment: 18 pages, 14 figures, Accepted by Ap

Hubble Space Telescope Grism Spectroscopy of Extreme Starbursts Across Cosmic Time: The Role of Dwarf Galaxies in the Star Formation History of the Universe

Near infrared slitless spectroscopy with the Wide Field Camera 3, onboard the Hubble Space Telescope, offers a unique opportunity to study low-mass galaxy populations at high-redshift ($z\sim$1-2). While most high$-z$ surveys are biased towards massive galaxies, we are able to select sources via their emission lines that have very-faint continua. We investigate the star formation rate (SFR)-stellar mass ($M_{\star}$) relation for about 1000 emission-line galaxies identified over a wide redshift range of $0.3 \lesssim z \lesssim 2.3$. We use the H$_{\alpha}$ emission as an accurate SFR indicator and correct the broadband photometry for the strong nebular contribution to derive accurate stellar masses down to $M_{\star} \sim 10^{7} M_{\odot}$. We focus here on a subsample of galaxies that show extremely strong emission lines (EELGs) with rest-frame equivalent widths ranging from 200 to 1500 \AA. This population consists of outliers to the normal SFR-$M_{\star}$ sequence with much higher specific SFRs ($> 10$ Gyr$^{-1}$). While on-sequence galaxies follow a continuous star formation process, EELGs are thought to be caught during an extreme burst of star formation that can double their stellar mass in less than $100$ Myr. The contribution of starbursts to the total star formation density appears to be larger than what has been reported for more massive galaxies in previous studies. In the complete mass range $8.2 <$ log($M_{\star}/M_{\odot}$) $< 10$ and a SFR lower completeness limit of about 2 $M_{\odot}$ yr$^{-1}$ (10 $M_{\odot}$ yr$^{-1}$) at $z\sim1$ ($z \sim 2$), we find that starbursts having EW$_{rest}$(H$_{\alpha}$)$>$ 300, 200, and 100 A contribute up to $\sim13$, 18, and 34 %, respectively, to the total SFR of emission-line selected sample at $z\sim1-2$. The comparison with samples of massive galaxies shows an increase in the contribution of starbursts towards lower masses.Comment: 11 pages, 6 figures. The Astrophysical Journal, in pres

Physical Properties of Emission-Line Galaxies at z ~ 2 from Near-Infrared Spectroscopy with Magellan FIRE

We present results from near-infrared spectroscopy of 26 emission-line galaxies at z ~ 2 obtained with the FIRE spectrometer on the Magellan Baade telescope. The sample was selected from the WISP survey, which uses the near-infrared grism of the Hubble Space Telescope Wide Field Camera 3 to detect emission-line galaxies over 0.3 < z < 2.3. Our FIRE follow-up spectroscopy (R~5000) over 1.0-2.5 micron permits detailed measurements of physical properties of the z~2 emission-line galaxies. Dust-corrected star formation rates for the sample range from ~5-100 M_sun yr-1. We derive a median metallicity for the sample of ~0.45 Z_sun, and the estimated stellar masses range from ~10^8.5 - 10^9.5 M_sun. The average ionization parameters measured for the sample are typically much higher than what is found for local star-forming galaxies. We derive composite spectra from the FIRE sample, from which we infer typical nebular electron densities of ~100-400 cm^-3. Based on the location of the galaxies and composite spectra on BPT diagrams, we do not find evidence for significant AGN activity in the sample. Most of the galaxies as well as the composites are offset in the BPT diagram toward higher [O III]/H-beta at a given [N II]/H-alpha, in agreement with other observations of z > 1 star-forming galaxies, but composite spectra derived from the sample do not show an appreciable offset from the local star-forming sequence on the [O III]/H-beta versus [S II]/H-alpha diagram. We infer a high nitrogen-to-oxygen abundance ratio from the composite spectrum, which may contribute to the offset of the high-redshift galaxies from the local star-forming sequence in the [O III]/H-beta versus [N II]/H-alpha diagram. We speculate that the elevated nitrogen abundance could result from substantial numbers of Wolf-Rayet stars in starbursting galaxies at z~2. (Abridged)Comment: Accepted for publication in Ap

El proceso de transición de servicios pediátricos a adultos: visión de adolescentes hospitalizados portadores de enfermedades crónicas

ResumenIntroducciónLas enfermedades crónicas durante la adolescencia son un gran desafío para el paciente, su familia y los proveedores de salud. La transición desde los servicios de salud pediátricos a adultos involucra el proceso de traspaso programado y planificado, de adolescentes portadores de enfermedades crónicas, para mantener una buena calidad de vida y desarrollo biopsicosocial. No existe, actualmente, un modelo único de transición. El objetivo del estudio es comprender el proceso de transición desde la perspectiva de adolescentes hospitalizados, para colaborar al diseño de un modelo acorde a las necesidades estudiadas.Pacientes y métodoIncluye entrevistas semiestructuradas a 13 adolescentes portadores de enfermedades crónicas, hospitalizados en 2 centros asistenciales de Santiago de Chile, en un estudio analítico-relacional, sostenido por una metodología de carácter cualitativo.ResultadosEn el análisis destacan 5 temas principales: experiencia de la vivencia de la enfermedad, importancia de la relación médico-paciente, concepto de autonomía limitado a lo farmacológico, ausencia de un proceso de transición propiamente dicho y la identificación de barreras y necesidades para una transición adecuada.ConclusionesEste estudio es pionero en Chile en explorar el fenómeno de la transición en adolescentes con enfermedades crónicas. Enfatiza la necesidad de reforzar el concepto de autocuidado y autonomía desde etapas tempranas del cuidado y la importancia de la planificación temprana de un proceso de transición saludable, de acuerdo a las necesidades detectadas por los propios adolescentes.AbstractIntroductionChronic illnesses during adolescence are a big challenge for the patient, his or her family, and health care providers. The transition from paediatric health services to adult health services involves a programmed and planned transfer process of adolescent sufferers of chronic illnesses, in order to maintain a high quality of life and bio-psycho-social development. There is currently no transition model. The objective of the study is to understand the transition process from the perspective of hospitalised adolescents to collaborate towards the design of a model that meets the needs studied.Patients and methodSemi-structured interviews with 13 adolescent sufferers of chronic illnesses, hospitalised in two healthcare centres in Santiago, Chile, in one analytical-relational study, supported by qualitative methodology.ResultsIn the analysis, 5 major themes stand out: experience of living with the illness, the importance of the doctor-patient relationship, the concept of limited autonomy to the pharmacology, the absence of the transition process as such, and the identification of barriers and needs for an adequate transition.ConclusionsThis study is new in Chile in that it explores the phenomenom of the transition of adolescents with chronic illnesses. It emphasises the need to reinforce the concept of self-care and autonomy from early stages of care, and the importance of early planning of a healthy transition process, in accordance to the detected needs of the adolescents themselves

Plan estratégico para Orión S.A.C.

El planeamiento estratégico de Orión S.A.C. sigue la metodología del modelo secuencial del proceso estratégico realizado por el doctor Fernando D´Alessio. Para el desarrollo del presente documento se reunió información por medio de cuestionarios aplicados a los jefes de línea, entrevistas al gerente de la empresa y se realizó el análisis de los estados financieros de la empresa. Posteriormente se identificó las estrategias que la compañía debe implementar para generar un posicionamiento que le permita aprovechar las condiciones del mercado en su sector y desarrollar sus potencialidades todo enmarcado en una visión, misión, valores y código de ética. Finalmente se concluyó que Orión S.A.C. es una empresa que cuenta con sólida capacidad financiera y personal altamente capacitado lo cual le permite ofrecer productos y servicios de calidad reconocida en el mercado. En el presente trabajo se ha recomendado principalmente el desarrollo de una alianza estratégica con una empresa internacional a fin de beneficiarse de la transferencia tecnológica y posicionamiento de marca, brindar una oferta integral para atender las necesidades de los clientes que incluya servicios relacionados e ingresar a sectores no relacionados a la minería como sector pesca y construcciónThe Orion S.A.C strategic planning follows the methodology of the strategic process sequential model by Dr. Fernando D'Alessio. For the development of this document information was collected through questionnaires applied to line managers, interviewing the manager of the company and analysis of financial statements of the company was performed. Subsequently strategies that the company must implement to generate a positioning itself to take advantage of market conditions in the sector and develop their potential all framed in a vision, mission, values and code of ethics was identified. Finally it was concluded that Orion S.A.C. is a solid company with highly trained staff and financial capacity which allows it to offer quality products and services recognized in the market. In this work it has been mainly recommending the development of a strategic alliance with an international company to benefit from technology transfer and branding, providing a comprehensive offering to meet the needs of customers including related services and enter sectors not related to mining like fisheries and constructionTesi

Low Masses and High Redshifts: The Evolution of the Mass-Metallicity Relation

We present the first robust measurement of the high redshift mass-metallicity (MZ) relation at 10^8 ≾ M/M_☉ ≾ 10^(10), obtained by stacking spectra of 83 emission-line galaxies with secure redshifts between 1.3 ≾ z ≾ 2.3. For these redshifts, infrared grism spectroscopy with the Hubble Space Telescope Wide Field Camera 3 is sensitive to the R_(23) metallicity diagnostic: ([O II] λλ3726, 3729 + [O III] λλ4959, 5007)/Hβ. Using spectra stacked in four mass quartiles, we find a MZ relation that declines significantly with decreasing mass, extending from 12+log(O/H) = 8.8 at M = 10^(9.8) M_☉, to 12+log(O/H) = 8.2 at M = 10^(8.2) M_☉. After correcting for systematic offsets between metallicity indicators, we compare our MZ relation to measurements from the stacked spectra of galaxies with M ≳ 10^(9.5) M_☉ and z ~ 2.3. Within the statistical uncertainties, our MZ relation agrees with the z ~ 2.3 result, particularly since our somewhat higher metallicities (by around 0.1 dex) are qualitatively consistent with the lower mean redshift (z = 1.76) of our sample. For the masses probed by our data, the MZ relation shows a steep slope which is suggestive of feedback from energy-driven winds, and a cosmological downsizing evolution where high mass galaxies reach the local MZ relation at earlier times. In addition, we show that our sample falls on an extrapolation of the star-forming main sequence (the SFR-M_* relation) at this redshift. This result indicates that grism emission-line selected samples do not have preferentially high star formation rates (SFRs). Finally, we report no evidence for evolution of the mass-metallicity-SFR plane; our stack-averaged measurements show excellent agreement with the local relation

Near-IR Integral Field Spectroscopy study of the Star Formation and AGN of the LIRG NGC 5135

We present a study of the central 2.3 kpc of NGC 5135, a nearby Luminous Infrared Galaxy (LIRG) with an AGN and circumnuclear starburst. Our main results are based on intermediate spectral resolution (~ 3000-4000) near infrared data taken with the SINFONI integral field spectrograph at the ESO VLT. The ionization of the different phases of the interstellar gas and the complex structures of the star formation have been mapped. Individual regions of interest have been identified and studied in detail. For the first time in this galaxy, we have detected the presence of a high excitation ionization cone centered on the AGN by using the [SiVI] (1.96 micron) line. So far, this structure is the largest reported in the literature for this coronal line, extending (in projection) as far as ~ 600 pc from the galaxy nucleus. In a complex spatial distribution, a variety of mechanisms are driving the gas ionization, including SNe remnant shocks, young stars and AGN photoionization. The excitation of the molecular gas, however, is mainly produced by X-rays and SNe remnant shocks. UV-mechanisms like fluorescence represent a marginal overall contribution to this process, contrary to the expectations we might have for a galaxy with a recent and strong star formation. Our SNe rate estimations from [FeII] (1.64 micron) are in excellent agreement with 6 cm radio emission predictions. Typical SNe rates between 0.01-0.04 yr^-1 were found for individual ~ 200 pc-scale regions, with an overall SNe rate of 0.4-0.5 yr^-1. Even though NGC 5135 has suffered a recent starburst (6-7 Myr ago), the data strongly suggest the presence of a second, older stellar population dominated by red giant/supergiant stars.Comment: Minor changes to previous version, including Fig. 1-4 captions, Fig. 4 units (upper panels) and reference list correction