Estudios de remanentes de supernova en medios altamente inhomogéneos

Esta tesis doctoral tiene como objetivo principal contribuir al conocimiento teórico y observacional, de remanentes de supernova (RSNs) que evolucionan en medios altamente inhomogéneos. El trabajo de investigación se basa en el análisis de observaciones en diferentes longitudes de ondas de remanentes galácticos, con énfasis en el estudio de la emisión de rayos X originada en este tipo de fuentes. La explosión de una supernova es un fenómeno altamente energético que produce un profundo impacto en el medio interestelar (MIE), debido a la cantidad de energía mecánica entregada y a los elementos pesados producidos, los cuales enriquecen el medio circundante. La propagación del frente de choque (o shock) de RSNs que interactúa con el gas y polvo del medio circundante, comprime, calienta, ioniza y disocia el material atómico y molecular, y como resultado se ve afectada en cierta medida la estructura dinámica de la galaxia. Como consecuencia, se observa una amplia variedad de remanentes de supernova con diferentes morfologías a lo largo de todo le espectro electromagnético, en particular en las bandas de radio, infrarrojo (IR) y de rayos X. El estudio de la morfología de los RSNs en frecuencias de rayos X, nos permite obtener información vital de las propiedades físicas y químicas de los plasmas emisores de rayos X y de las diferentes condiciones del medio en el cual esta clase de objetos evolucionan. A través de un enfoque multi-longitud de ondas, es posible introducir diferentes escenarios que permiten caracterizar el medio circundante y como éste condiciona la evolución de los RSNs. Además, el estudio de estos objetos en las frecuencias de rayos X e infrarrojo, puede utilizarse como una herramienta de diagnóstico para discernir los tipos posibles de progenitores. Los objetos de estudio incluidos en esta tesis son los remanentes G332.5-5.6, G306.3-0.9, G309.2-0.6 y el fragmento G del RSN de Vela. Estos objetos se estudiaron a partir de observaciones disponibles en bases de datos públicas en longitudes de rayos X, radio e infrarrojo. En el rango de emisión de rayos X, se realizaron estudios morfológicos, construyendo imágenes en diferentes rangos de energía, mapas de energía media, y de ancho equivalente para ciertas líneas de emisión. Se hicieron estudios espectroscópicos con alta resolución espacial de la emisión de rayos X y se propusieron posibles progenitores a partir de las información de las abundancias de elementos pesados obtenidos de los ajustes espectrales y de métodos morfológicos.Facultad de Ciencias Astronómicas y Geofísica

Detailed study of SNR G306.3–0.9 using XMM-Newton and Chandra observations

Aims. We aim to study the spatial distribution of the physical and chemical properties of the X-ray emitting plasma of the supernova remnant (SNR) G306.3-0.9 in detail to obtain constraints on its ionization stage, the progenitor supernova explosion, and the age of the remnant. Methods. We used combined data from XMM-Newton and Chandra observatories to study the X-ray morphology of G306.3-0.9 in detail. A spatially resolved spectral analysis was used to obtain physical and geometrical parameters of different regions of the remnant. Spitzer infrared observations, available in the archive, were also used to constrain the progenitor supernova and study the environment in which the remnant evolved. Results. The X-ray morphology of the remnant displays a non-uniform structure of semi-circular appearance, with a bright southwest region and very weak or almost negligible X-ray emission in its northern part. These results indicate that the remnant is propagating in a non-uniform environment as the shock fronts are encountering a high-density medium, where enhanced infrared emission is detected. The X-ray spectral analysis of the selected regions shows distinct emission-line features of several metal elements, confirming the thermal origin of the emission. The X-ray spectra are well represented by a combination of two absorbed thermal plasma models: one in equilibrium ionization (VAPEC) with a mean temperature of ∼0.19 keV, and another out of equilibrium ionization (VNEI) at a higher temperature of ∼1.1 or 1.6-1.9 keV. For regions located in the northeast, central, and southwest part of the SNR, we found elevated abundances of Si, S, Ar, Ca, and Fe, typical of ejecta material. The outer regions located northwest and south show values of the abundances above solar but lower than to those found in the central regions. This suggests that the composition of the emitting outer parts of the SNR is a combination of ejecta and shocked material of the interstellar medium. The comparison between the S/Si, Ar/Si, and Ca/Si abundances ratios (1.75, 1.27, and 2.72 in the central region, respectively), favor a Type Ia progenitor for this remnant, a result that is also supported by an independent morphological analysis using the X-ray and 24 μm IR data.Facultad de Ciencias Astronómicas y GeofísicasInstituto Argentino de Radioastronomí

An X-ray characterization of the central region of the supernova remnant G332.5-5.6

Aims. We present an X-ray analysis of the central region of supernova remnant (SNR) G332.5-5.6 through an exhaustive analysis of XMM-Netwon observations with complementary infrared observations. We characterize and discuss the origin of the observed X-ray morphology, which presents a peculiar plane edge over the west side of the central region. Methods. The morphology and spectral properties of the X-ray SNR were studied using a single full frame XMM-Netwon observation in the 0.3 to 10.0 keV energy band. Archival infrared WISE observations at 8, 12 and 24 μm were also used to investigate the properties of the source and its surroundings at different wavelengths. Results. The results show that the extended X-ray emission is predominantly soft (0.3-1.2 keV) and peaks around 0.5 keV, which shows that it is an extremely soft SNR. X-ray emission correlates very well with central regions of bright radio emission. On the west side the radio/X-ray emission displays a plane-like feature with a terminal wall where strong infrared emission is detected. Our spatially resolved X-ray spectral analysis confirms that the emission is dominated by weak atomic emission lines of N, O, Ne, and Fe, all of them undetected in previous X-ray studies. These characteristics suggest that the X-ray emission is originated in an optically thin thermal plasma, whose radiation is well fitted by a non-equilibrium ionization collisional plasma (VNEI) X-ray emission model. Our study favors a scenario where G332.5-5.6 is expanding in a medium with an abrupt density change (the wall), likely a dense infrared emitting region of dust on the western side of the source.Facultad de Ciencias Astronómicas y GeofísicasInstituto Argentino de Radioastronomí

Indications of a Si-rich bilateral jet of ejecta in the Vela SNR observed with XMM-Newton

Context. The Vela supernova remnant displays several ejecta, which are fragment-like features protruding beyond the front of its primary blast shock wave. They appear to be "shrapnel", bowshock-shaped relics of the supernova explosion. One of these pieces of shrapnel (A), located in the northeastern edge of the remnant, is peculiar because its X-ray spectrum exhibits a high Si abundance, in contrast to the other observed ejecta fragments, which show enhanced O, Ne, and Mg abundances. Aims. In this Letter we present the analysis of another ejecta fragment located opposite to shrapnel A with respect to the center of the shell, in the southwestern boundary of the remnant, named shrapnel G. We aim to fully characterize its X-ray emission to gather new information about the core-collapse supernova explosion mechanism. Methods. We thoroughly analyzed a dedicated XMM-Newton observation of shrapnel G by producing background-subtracted and exposure-corrected maps in different energy ranges, which we complemented with a spatially resolved spectral analysis of the X-ray emission. Results. The fragment presents a bowshock-like shape with its anti-apex pointing to the center of the remnant. Its X-ray spectrum is best fit by a thermal plasma out of equilibrium of ionization with low O and Fe, roughly solar Ne and Mg, and a significantly high Si abundance, which is required to fit a very clear Si line at ∼1.85 keV. Its chemical composition and spectral properties are compatible with those of shrapnel A, which is located on the opposite side of the remnant. Conclusions. As a consequence of the nucleosynthesis, pieces of Si-rich shrapnel are expected to originate in deeper layers of the progenitor star compared to ejecta with lower-Z elements. A high velocity and density contrast with respect to the surrounding ejecta are necessary to make shrapnel A and G overtake the forward shock. The line connecting shrapnel A and G crosses almost exactly the expansion center of the remnant, strongly suggesting a Si-rich jet-counterjet structure, reminiscent of that observed in the young remnant Cas A.Facultad de Ciencias Astronómicas y Geofísica

Detailed study of SNR G306.3–0.9 using XMM-Newton and Chandra observations

Aims. We aim to study the spatial distribution of the physical and chemical properties of the X-ray emitting plasma of the supernova remnant (SNR) G306.3-0.9 in detail to obtain constraints on its ionization stage, the progenitor supernova explosion, and the age of the remnant. Methods. We used combined data from XMM-Newton and Chandra observatories to study the X-ray morphology of G306.3-0.9 in detail. A spatially resolved spectral analysis was used to obtain physical and geometrical parameters of different regions of the remnant. Spitzer infrared observations, available in the archive, were also used to constrain the progenitor supernova and study the environment in which the remnant evolved. Results. The X-ray morphology of the remnant displays a non-uniform structure of semi-circular appearance, with a bright southwest region and very weak or almost negligible X-ray emission in its northern part. These results indicate that the remnant is propagating in a non-uniform environment as the shock fronts are encountering a high-density medium, where enhanced infrared emission is detected. The X-ray spectral analysis of the selected regions shows distinct emission-line features of several metal elements, confirming the thermal origin of the emission. The X-ray spectra are well represented by a combination of two absorbed thermal plasma models: one in equilibrium ionization (VAPEC) with a mean temperature of ∼0.19 keV, and another out of equilibrium ionization (VNEI) at a higher temperature of ∼1.1 or 1.6-1.9 keV. For regions located in the northeast, central, and southwest part of the SNR, we found elevated abundances of Si, S, Ar, Ca, and Fe, typical of ejecta material. The outer regions located northwest and south show values of the abundances above solar but lower than to those found in the central regions. This suggests that the composition of the emitting outer parts of the SNR is a combination of ejecta and shocked material of the interstellar medium. The comparison between the S/Si, Ar/Si, and Ca/Si abundances ratios (1.75, 1.27, and 2.72 in the central region, respectively), favor a Type Ia progenitor for this remnant, a result that is also supported by an independent morphological analysis using the X-ray and 24 μm IR data.Facultad de Ciencias Astronómicas y GeofísicasInstituto Argentino de Radioastronomí

An X-ray characterization of the central region of the supernova remnant G332.5-5.6

Aims. We present an X-ray analysis of the central region of supernova remnant (SNR) G332.5-5.6 through an exhaustive analysis of XMM-Netwon observations with complementary infrared observations. We characterize and discuss the origin of the observed X-ray morphology, which presents a peculiar plane edge over the west side of the central region. Methods. The morphology and spectral properties of the X-ray SNR were studied using a single full frame XMM-Netwon observation in the 0.3 to 10.0 keV energy band. Archival infrared WISE observations at 8, 12 and 24 μm were also used to investigate the properties of the source and its surroundings at different wavelengths. Results. The results show that the extended X-ray emission is predominantly soft (0.3-1.2 keV) and peaks around 0.5 keV, which shows that it is an extremely soft SNR. X-ray emission correlates very well with central regions of bright radio emission. On the west side the radio/X-ray emission displays a plane-like feature with a terminal wall where strong infrared emission is detected. Our spatially resolved X-ray spectral analysis confirms that the emission is dominated by weak atomic emission lines of N, O, Ne, and Fe, all of them undetected in previous X-ray studies. These characteristics suggest that the X-ray emission is originated in an optically thin thermal plasma, whose radiation is well fitted by a non-equilibrium ionization collisional plasma (VNEI) X-ray emission model. Our study favors a scenario where G332.5-5.6 is expanding in a medium with an abrupt density change (the wall), likely a dense infrared emitting region of dust on the western side of the source.Facultad de Ciencias Astronómicas y GeofísicasInstituto Argentino de Radioastronomí

Indications of a Si-rich bilateral jet of ejecta in the Vela SNR observed with XMM-Newton

Context. The Vela supernova remnant displays several ejecta, which are fragment-like features protruding beyond the front of its primary blast shock wave. They appear to be "shrapnel", bowshock-shaped relics of the supernova explosion. One of these pieces of shrapnel (A), located in the northeastern edge of the remnant, is peculiar because its X-ray spectrum exhibits a high Si abundance, in contrast to the other observed ejecta fragments, which show enhanced O, Ne, and Mg abundances. Aims. In this Letter we present the analysis of another ejecta fragment located opposite to shrapnel A with respect to the center of the shell, in the southwestern boundary of the remnant, named shrapnel G. We aim to fully characterize its X-ray emission to gather new information about the core-collapse supernova explosion mechanism. Methods. We thoroughly analyzed a dedicated XMM-Newton observation of shrapnel G by producing background-subtracted and exposure-corrected maps in different energy ranges, which we complemented with a spatially resolved spectral analysis of the X-ray emission. Results. The fragment presents a bowshock-like shape with its anti-apex pointing to the center of the remnant. Its X-ray spectrum is best fit by a thermal plasma out of equilibrium of ionization with low O and Fe, roughly solar Ne and Mg, and a significantly high Si abundance, which is required to fit a very clear Si line at ∼1.85 keV. Its chemical composition and spectral properties are compatible with those of shrapnel A, which is located on the opposite side of the remnant. Conclusions. As a consequence of the nucleosynthesis, pieces of Si-rich shrapnel are expected to originate in deeper layers of the progenitor star compared to ejecta with lower-Z elements. A high velocity and density contrast with respect to the surrounding ejecta are necessary to make shrapnel A and G overtake the forward shock. The line connecting shrapnel A and G crosses almost exactly the expansion center of the remnant, strongly suggesting a Si-rich jet-counterjet structure, reminiscent of that observed in the young remnant Cas A.Facultad de Ciencias Astronómicas y Geofísica

Observaciones combinadas XMM-Newton/Chandra del remanente de supernova G306.3-0.9

In this paper we study the spatial and spectral distribution of the physical and chemical properties of the supernova remnant G306.3-0.9 by using data of the X-rays telescopes XMM-Newton and Chandra, which we complement with radio and infrared information in order to study the morphology of the source and the effect of the shock wave in the interestelar medium. The results show a non-uniform morphology of the emission, dominated by thermal radiation with high values of Ne, Mg, S, Ca, Ar and Fe in the central region, typical of ejecta material. Also, using an infrared flux distribution, we could restrict the type of the progenitor responsible of the supernova phenomena.En este trabajo estudiamos la distribución espacial y espectral de las propiedades físicas y químicas del remanente de supernova G306.3-0.9 utilizando datos de los telescopios de rayos X XMM-Newton y Chandra, que complementamos con información de radio e infrarrojos para estudiar la morfología de la fuente y el efecto de la onda de choque en el medio interestelar. Los resultados muestran una morfología no uniforme de la emisión, dominada por radiación térmica con altos valores de Ne, Mg, S, Ca, Ar y Fe en la región central, propios del material eyectado. Además, utilizando una distribución de flujo infrarrojo, podríamos restringir el tipo de progenitor responsable de los fenómenos de supernova.Fil: Filócomo, Agostina. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Combi, Jorge Ariel. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: García, Federico. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Suárez, Alejandra Etelvina. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Luque Escamilla, L. P.. Universidad de Jaén; EspañaFil: Paron, Sergio Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio(i); ArgentinaReunión Anual de la Asociación Argentina de AstronomíaLa PlataArgentinaUniversidad Nacional de La Plata. Facultad de Ciencias Astronómicas y GeofísicasUniversidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plat

Design concepts for the Cherenkov Telescope Array CTA: An advanced facility for ground-based high-energy gamma-ray astronomy

Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA.La lista completa de autores que integran el documento puede consultarse en el archivo.Departamento de AeronáuticaFacultad de IngenieríaInstituto Argentino de RadioastronomíaFacultad de Ciencias Astronómicas y Geofísica

Estudios de remanentes de supernova en medios altamente inhomogeneos

Esta tesis doctoral tiene como objetivo principal contribuir al conocimiento teórico y observacional, de remanentes de supernova (RSNs) que evolucionan en medios altamente inhomogéneos. El trabajo de investigación se basa en el análisis de observaciones en diferentes longitudes de ondas de remanentes galácticos, con énfasis en el estudio de la emisión de rayos X originada en este tipo de fuentes.La explosión de una supernova es un fenómeno altamente energético que produce un profundo impacto en el medio interestelar (MIE), debido a la cantidad de energía mecánica entregada y a los elementos pesados producidos, los cuales enriquecen el medio circundante. La propagación del frente de choque (o shock) de RSNs que interactúa con el gas y polvo del medio circundante, comprime, calienta, ioniza y disocia el material atómico y molecular, ycomo resultado se ve afectada en cierta medida la estructura dinámica de la galaxia. Como consecuencia, se observa una amplia variedad de remanentes de supernova con diferentes morfologías a lo largo de todo le espectro electromagnético, en particular en las bandas de radio, infrarrojo (IR) y de rayos X. El estudio de la morfología de los RSNs en frecuencias de rayos X, nos permite obtener información vital de las propiedades físicas y químicas de los plasmas emisores de rayos X y de las diferentes condiciones del medio en el cual esta clase de objetos evolucionan. A través de un enfoque multi-longitud de ondas, es posible introducirdiferentes escenarios que permiten caracterizar el medio circundante y como éste condiciona la evolución de los RSNs. Además, el estudio de estos objetos en las frecuencias de rayos Xe infrarrojo, puede utilizarse como una herramienta de diagnóstico para discernir los tipos posibles de progenitores.Los objetos de estudio incluidos en esta tesis son los remanentes G332.5-5.6, G306.3-0.9, G309.2-0.6 y el fragmento G del RSN de Vela. Estos objetos se estudiaron a partir de observaciones disponibles en bases de datos públicas en longitudes de rayos X, radio e infrarrojo. En el rango de emisión de rayos X, se realizaron estudios morfológicos, construyendo imágenes en diferentes rangos de energía, mapas de energía media, y de ancho equivalente para ciertas líneas de emisión. Se hicieron estudios espectroscópicos con alta resolución espacial de la emisión de rayos X y se propusieron posibles progenitores a partir de las información de las abundancias de elementos pesados obtenidos de los ajustes espectrales y de métodos morfológicos.Fil: Suárez, Alejandra Etelvina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; Argentin