Publication: Modelado auto-consistente de la emisión de estrellas y polvo en galaxias luminosas en IR a redshift intermedio
Loading...
Official URL
Full text at PDC
Publication Date
2016-02-09
Authors
Advisors (or tutors)
Editors
Journal Title
Journal ISSN
Volume Title
Publisher
Universidad Complutense de Madrid
Citations
Exportar
Abstract
Las distribuciones espectrales de energía (SEDs) de galaxias con polvo y formación estelar a desplazamientos al rojo intermedio son caracterizadas usualmente con modelos que asumen un ́unico brote para representar las historia de formación estelar (SFH) de las distintas poblaciones que constituyen estos objetos. Adeḿas, la relación entre la atenuación de la emisión estelar en el espectro visible debida al polvo y su posterior re-emisi ́on en el infrarrojo lejano (FIR) ha sido desestimada cuando se determinan las propiedades físicas de estas galaxias, como la masa y la tasa de formación estelar (SFR). En esta tesis investigamos las propiedades estelares de una muestra de 19 galaxias seleccionadas en el FIR en el intervalo de desplazamiento al rojo 0.6 ≤ z ≤ 1.5, analizando su SEDs desde el UV hasta el FIR. La muestra se deriva de objetos con 3 o ḿas medidas fotométricas en el FIR, una tomada a 70 μm con MIPS en Spitzer y ḿınimo otras dos adquiridas con PACS y/o SPIRE en Herschel en la región del Subaru/XMMNewton Deep Survey. Esta fotometría permite estimar de forma precisa la luminosidad total en el IR (LTIR, integrada entre 8 y 1000 μm) de estas galaxias brillantes en el IR (LIRGs and ULIRGs). Las SEDs desde el UV hasta el FIR son ajustadas usando modelos de poblaciones estelares y emisión del polvo provenientes de programas (Synthesizer y CIGALE) que conectan usando técnicas de balance energético la atenuación de la emisión estelar debida al polvo y su posterior re-emisión en el FIR. Asumimos una SFH de referencia descrita por una población estelar joven traslapando una población estelar evolucionada, ambas caracterizadas con funciones exponenciales decrecientes. Determinamos el impacto en nuestros resultados cuando se constri ˜ne o no, la atenuación de la emisión estelar usando el método de balance energético, y su efecto en combinación con modelos que asumen una población estelar en lugar de dos. Este análisis con balance energético permite: 1) caracterizar las poblaciones estelares de (U)LIRGs con propiedades físicas robustas determinadas al romper la degeneración edad-polvo; 2) estimar adecuadamente la cantidad de atenuación de la emisión estelar en estas galaxias; 3) mejorar las estimaciones de masa estelar y SFR en (U)LIRGs; 4) calcular el tiempo que transcurren las galaxias en la fase (U)LIRG, y la masa estelar ix x que se agrega a las galaxias en dicha fase; 5) determinar que propiedades de las poblaciones estelares ejercen mayor impacto en la estimación de masas estelares y SFRs en (U)LIRGs; y 6) evaluar como las suposiciones a priori y el uso de programas diferentes en el modelado afectan los resultados en propiedades estelares de (U)LIRGs.
The Spectral Energy Distributions (SEDs) of dusty star-forming galaxies at intermediate redshifts are usually characterized with models that naively assume only one burst (short or extended in time) as representative star formation history (SFH) of the stellar populations of these galaxies, which are obviously much more complex. Moreover, the relation between the optical light attenuation and posterior re-emission at far-infrared (FIR) wavelengths due to dust has been traditionally unappreciated when deriving the physical properties of these objects, such as the stellar mass and star formation rate (SFR). In this thesis we investigate the stellar properties of a FIR selected sample of 19 star-forming galaxies in the redshift range 0.6 ≤ z ≤ 1.5 by analyzing their UV-to- FIR SEDs. The sample is based in three or more FIR detections, one from Spitzer- MIPS 70 μm and at least two from PACS and/or SPIRE on Herschel observed in the Subaru/XMM-Newton Deep Survey field. These FIR data allow us to accurately determine the total infrared luminosity (LTIR, integrated from 8 to 1000 μm) of such (ultra)- luminous infrared galaxies (LIRGs and ULIRGs). The full UV-to-FIR SEDs are fitted to stellar population and dust emission models using codes (Synthesizer and CIGALE) which manage the attenuation of stellar light and dust re-emission with energy balance techniques. We assume a fiducial SFH depicted by a young stellar population on top of an evolved population, each parameterized with a decaying exponential function. We compare the impact on our results of including and excluding the FIR data to constrain the amount of attenuation of stellar light, as well of using this constrain assuming one single stellar population instead of two. Our auto-consistent analysis of the stellar light obscuration and dust emission provides: 1) reliable physical properties of the stellar populations of (U)LIRGs by breaking the age-dust degeneracy; 2) accurate values of the amount of attenuation of stellar light in these galaxies; 3) improved stellar mass and SFR estimations of IR-bright galaxies; 4) estimates of the time spent by galaxies in the (U)LIRG phase, and of the corresponding amount of stellar mass added in this phase; 5) the stellar properties having more impact in the determination of stellar masses and SFRs of IR-bright galaxies; and 6) an evaluation of how a priori assumptions and usage v vi of different codes in the modeling affect the results for the stellar population properties of (U)LIRGs.
The Spectral Energy Distributions (SEDs) of dusty star-forming galaxies at intermediate redshifts are usually characterized with models that naively assume only one burst (short or extended in time) as representative star formation history (SFH) of the stellar populations of these galaxies, which are obviously much more complex. Moreover, the relation between the optical light attenuation and posterior re-emission at far-infrared (FIR) wavelengths due to dust has been traditionally unappreciated when deriving the physical properties of these objects, such as the stellar mass and star formation rate (SFR). In this thesis we investigate the stellar properties of a FIR selected sample of 19 star-forming galaxies in the redshift range 0.6 ≤ z ≤ 1.5 by analyzing their UV-to- FIR SEDs. The sample is based in three or more FIR detections, one from Spitzer- MIPS 70 μm and at least two from PACS and/or SPIRE on Herschel observed in the Subaru/XMM-Newton Deep Survey field. These FIR data allow us to accurately determine the total infrared luminosity (LTIR, integrated from 8 to 1000 μm) of such (ultra)- luminous infrared galaxies (LIRGs and ULIRGs). The full UV-to-FIR SEDs are fitted to stellar population and dust emission models using codes (Synthesizer and CIGALE) which manage the attenuation of stellar light and dust re-emission with energy balance techniques. We assume a fiducial SFH depicted by a young stellar population on top of an evolved population, each parameterized with a decaying exponential function. We compare the impact on our results of including and excluding the FIR data to constrain the amount of attenuation of stellar light, as well of using this constrain assuming one single stellar population instead of two. Our auto-consistent analysis of the stellar light obscuration and dust emission provides: 1) reliable physical properties of the stellar populations of (U)LIRGs by breaking the age-dust degeneracy; 2) accurate values of the amount of attenuation of stellar light in these galaxies; 3) improved stellar mass and SFR estimations of IR-bright galaxies; 4) estimates of the time spent by galaxies in the (U)LIRG phase, and of the corresponding amount of stellar mass added in this phase; 5) the stellar properties having more impact in the determination of stellar masses and SFRs of IR-bright galaxies; and 6) an evaluation of how a priori assumptions and usage v vi of different codes in the modeling affect the results for the stellar population properties of (U)LIRGs.
Description
Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Físicas, Departamento de Astrofísica y Ciencias de la Atmósfera, leída el 17-12-2015