Testeando Supernovas de tipo II como indicadores de distancia en el infrarrojo cercano
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2019
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en
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Universidad Andrés Bello
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Resumen
Motivado por las ventajas de observar en longitudes de onda de infrarrojo cercano, en este trabajo
investigo a las supernovas de tipo II (SNs II) como indicadoras de distancia en esas longitudes de
onda mediante el método de la magnitud fotosférica (PMM). Para el análisis uso fotometría BVIJH
y espectroscopía óptica de 24 SNs II durante la fase fotosférica. Para corregir la fotometría por
efectos de extinción y corrimiento al rojo, calculo las extinctiones en bandas anchas total-a-selectiva
y las correcciones K hasta z = 0:032. Para estimar excesos de color en la galaxias huéspedes, uso
el método de la curva color color con VI versus BV como combinación de color. Calibro el
PMM usando cuatro SNs II en galaxias con distancias medidas con la punta de la rama gigante roja
(TRGB). Entre las 24 SNs II, nueve estan a cz > 2000 km s1, las que uso para construir diagramas
de Hubble (DHs). Para explorar más a fondo la precisión de las distancias PMM, incluyo en los
DH las cuatro SNs usadas para la calibración y otras dos en galaxias con distancias medidas con
Cefeidas o SN Ia. Con un conjunto de 15 SNs II obtengo un valor rms en el DH de 0.13 mag
para la banda J, que se compara con el valor rms de 0.15–0.26 para bandas ópticas. Esto refleja
los beneficios de medir distancias PMM con fotometría en infrarrojo cercano en vez de fotometría
óptica. Con esta evidencia, puedo establecer la precisión de las distancias PMM con la banda J bajo
un 10 por ciento con un nivel de confianza de un 99 por ciento.
Para probar el resultado anterior, llevé a cabo una campaña observacional para obtener curvas de
luz ópticas y en infrarrojo cercano junto con al menos un espectro óptico por SN. De esta nueva
muestra de SNs, seleccioné una submuestra de 24 SNs II (0:013 < z < 0:033) las que son ideales
para calcular distancias PMM. Complemento esta submuestra con siete SNs II (z > 0:013) usadas en
Rodríguez et al. (2019). Con este conjunto de 31 SNs II, encuentro que una corrección por el término
de color V-I para dar cuenta de la extinci´on en la galaxia huésped funciona mejor que los excesos
de color obtenidos con el m´etodo de la curva color-color. Construyendo DHs, obtengo valores rms
de 0.24–0.26 mag con las bandas BVI mientras que con JH obtengo valores rms de 0.21 mag. Esto
refuerza los beneficios de medir distancias PMM con fotometría en infrarrojo cercano en vez de
fotometría óptica. Con esta nueva evidencia, puedo establecer la precisión de las distancias PMM
con bandas en infrarrojo cercano en 9:7+2:62:4 por ciento con un nivel de confianza del 95 por ciento.
Calibrando las distancias PMM con cuatro SNs II en galaxias con distancias TRGB, y usando el DH
en la banda H, mido una constante de Hubble de H0 = 69:8 1:6(stat) 2:8(sys) km s1 Mpc1
(un 4.6 por ciento de error) usando la calibración TRGB de Jang and Lee (2017b).
Para analizar el efecto de los valores atípicos sobre las SNs II como indicadores de distancias con el
PMM, en este trabajo presento fotometría óptica e infrarroja de tres SNs II, a saber, SN 2008bm,
SN 2009aj y SN 2009au. Estas SNs muestran las siguientes características comunes: signos de
interacción temprana del material eyectado con material circunestelar (CSM), colores BV azules,
debilidad de lineas metálicas, bajas velocidades de expansión y magnitudes absolutas en la banda
V 2–3 mag más brillantes que las esperadas para SNs II basado en sus velocidades de expansión.
Dos SNs más reportadas en la literatura (SN 1983K y LSQ13fn) comparten propiedades similares a
nuestra muestra. Analizando este set de cinco SNs II luminosas con bajas velocidades de expansión
(LLEV), encuentro que sus propiedades pueden ser reproducidas asumiendo interacción entre el
material eyectado y el CSM que dura entre 3–6 semanas después de la explosión. La contribución
de esta interacción al campo de radiación parece ser la componente dominante que determina la
debilidad de lineas metálicas observada en los espectros en vez de la metalicidad del progenitor.
Basado en simulaciones hidrodin´amicas, Encuentro que la interacción del material eyectado con
un CSM de 3:6 M puede reproducir las curvas de luz y las velocidades de expansión de la SN
2009aj. Usando datos recogidos por la encuesta CHASE, Estimo un límite superior para la fracción
de LLEV SNs II de 1.9–4.7 por ciento de todas las SNs II normales. Con la muestra actual, no es
claro si los eventos LLEV presentan un nuevo subtipo de SNs II o si son el extremo de un continuo,
mediado por la interacción con un CSM, con el resto de la población de SNs II normales. Basado en
la muestra actual, encuentro que las LLEV SNs II no deberían representar un contaminante severo
en el uso de SNs II normales como indicadores de distancias con el PMM.
Motivated by the advantages of observing at near-IR wavelengths, in this work I investigate Type II supernovae (SNe II) as distance indicators at those wavelengths through the Photospheric Magnitude Method (PMM). For the analysis, I use BVIJH photometry and optical spectroscopy of 24 SNe II during the photospheric phase. To correct photometry for extinction and redshift effects, I compute total-to-selective broadband extinction ratios and K-corrections up to z = 0:032. To estimate host galaxy colour excesses, I use the colour-colour curve method with the VI versus BV as colour combination. I calibrate the PMM using four SNe II in galaxies having Tip of the Red Giant Branch (TRGB) distances. Among the 24 SNe II, nine are at cz > 2000 km s1, which I use to construct Hubble diagrams (HDs). To further explore the PMM distance precision, I include into HDs the four SNe used for calibration and other two in galaxies with Cepheid and SN Ia distances. With a set of 15 SNe II I obtain a HD rms of 0.13 mag for the J-band, which compares to the rms of 0.15–0.26 mag for optical bands. This reflects the benefits of measuring PMM distances with near-IR instead of optical photometry. With this evidence, I can set the PMM distance precision with J-band below 10 per cent with a confidence level of 99 per cent. To test the previous result, I carried out an observational campaign to obtain optical and near-IR light curves of SNe II along with at least one optical spectrum per SN. From this new SN sample, I selected a subsample of 24 SNe II (0:013 < z < 0:033) which are suitable to compute PMM distances. I complement this subsample with seven SNe II (z > 0:013) used in Rodr´ıguez et al. (2019). With this set of 31 SNe II, I find that a VI colour-term correction to account for host galaxy extinction works better than the colour excesses obtained with the colour-colour curve method. Constructing Hubble diagrams (HDs), I obtain rms values of 0.24–0.26 mag with BVI bands, while with JH I obtain a rms of 0.21 mag. This reinforces the benefits of measuring PMM distances with near-IR instead of optical photometry. With this new evidence, I can set the PMM distance precision with near-IR bands to be 9:7+2:6 2:4 per cent at a confidence level of 95 per cent. Calibrating the PMM distances with four SNe II in galaxies with Tip of the Red Giant Branch (TRGB) distances, and using the H-band HD, I measure a Hubble constant of H0 = 69:8 1:6(stat) 2:8(sys) km s1 Mpc1 (a 4.6 per cent error) using the TRGB calibration of Jang and Lee (2017b). In order to analyse the effect of outliers over SNe II as distance indicators with the PMM, in this work I present optical and near-IR photometry of three Type II supernovae (SNe II), namely SN 2008bm, SN 2009aj, and SN 2009au. These SNe display the following common characteristics: signs of early interaction of the ejecta with circumstellar material (CSM), blue BV colours, weakness of metal lines, low expansion velocities, and V-band absolute magnitudes 2–3 mag brighter than those expected for normal SNe II based on their expansion velocities. Two more SNe reported in the literature (SN 1983K and LSQ13fn) share properties similar to our sample. Analysing this set of five luminous with low expansion velocities (LLEV) SNe II, I find that their properties can be reproduced assuming ejecta-CSM interaction that lasts between 3-6 weeks post explosion. The contribution of this interaction to the radiation field seems to be the dominant component determining the observed weakness of metal lines in the spectra rather than the progenitor metallicity. Based on hydrodynamic simulations, I find that the interaction of the ejecta with a CSM of 3:6 M can reproduce the light curves and expansion velocities of SN 2009aj. Using data collected by the CHASE survey, I estimate an upper limit for the LLEV SNe II fraction to be 1.9–4.7 per cent of all normal SNe II. With the current data-set, it is not clear whether LLEV events present a new sub-type of SNe II, or whether they are the extreme of a continuum mediated by CSM interaction with the rest of the normal SN II population. Based on the current sample, I find that the LLEV SNe II should not represent a severe contaminant in the use of normal SNe II as distance indicators with the PMM.
Motivated by the advantages of observing at near-IR wavelengths, in this work I investigate Type II supernovae (SNe II) as distance indicators at those wavelengths through the Photospheric Magnitude Method (PMM). For the analysis, I use BVIJH photometry and optical spectroscopy of 24 SNe II during the photospheric phase. To correct photometry for extinction and redshift effects, I compute total-to-selective broadband extinction ratios and K-corrections up to z = 0:032. To estimate host galaxy colour excesses, I use the colour-colour curve method with the VI versus BV as colour combination. I calibrate the PMM using four SNe II in galaxies having Tip of the Red Giant Branch (TRGB) distances. Among the 24 SNe II, nine are at cz > 2000 km s1, which I use to construct Hubble diagrams (HDs). To further explore the PMM distance precision, I include into HDs the four SNe used for calibration and other two in galaxies with Cepheid and SN Ia distances. With a set of 15 SNe II I obtain a HD rms of 0.13 mag for the J-band, which compares to the rms of 0.15–0.26 mag for optical bands. This reflects the benefits of measuring PMM distances with near-IR instead of optical photometry. With this evidence, I can set the PMM distance precision with J-band below 10 per cent with a confidence level of 99 per cent. To test the previous result, I carried out an observational campaign to obtain optical and near-IR light curves of SNe II along with at least one optical spectrum per SN. From this new SN sample, I selected a subsample of 24 SNe II (0:013 < z < 0:033) which are suitable to compute PMM distances. I complement this subsample with seven SNe II (z > 0:013) used in Rodr´ıguez et al. (2019). With this set of 31 SNe II, I find that a VI colour-term correction to account for host galaxy extinction works better than the colour excesses obtained with the colour-colour curve method. Constructing Hubble diagrams (HDs), I obtain rms values of 0.24–0.26 mag with BVI bands, while with JH I obtain a rms of 0.21 mag. This reinforces the benefits of measuring PMM distances with near-IR instead of optical photometry. With this new evidence, I can set the PMM distance precision with near-IR bands to be 9:7+2:6 2:4 per cent at a confidence level of 95 per cent. Calibrating the PMM distances with four SNe II in galaxies with Tip of the Red Giant Branch (TRGB) distances, and using the H-band HD, I measure a Hubble constant of H0 = 69:8 1:6(stat) 2:8(sys) km s1 Mpc1 (a 4.6 per cent error) using the TRGB calibration of Jang and Lee (2017b). In order to analyse the effect of outliers over SNe II as distance indicators with the PMM, in this work I present optical and near-IR photometry of three Type II supernovae (SNe II), namely SN 2008bm, SN 2009aj, and SN 2009au. These SNe display the following common characteristics: signs of early interaction of the ejecta with circumstellar material (CSM), blue BV colours, weakness of metal lines, low expansion velocities, and V-band absolute magnitudes 2–3 mag brighter than those expected for normal SNe II based on their expansion velocities. Two more SNe reported in the literature (SN 1983K and LSQ13fn) share properties similar to our sample. Analysing this set of five luminous with low expansion velocities (LLEV) SNe II, I find that their properties can be reproduced assuming ejecta-CSM interaction that lasts between 3-6 weeks post explosion. The contribution of this interaction to the radiation field seems to be the dominant component determining the observed weakness of metal lines in the spectra rather than the progenitor metallicity. Based on hydrodynamic simulations, I find that the interaction of the ejecta with a CSM of 3:6 M can reproduce the light curves and expansion velocities of SN 2009aj. Using data collected by the CHASE survey, I estimate an upper limit for the LLEV SNe II fraction to be 1.9–4.7 per cent of all normal SNe II. With the current data-set, it is not clear whether LLEV events present a new sub-type of SNe II, or whether they are the extreme of a continuum mediated by CSM interaction with the rest of the normal SN II population. Based on the current sample, I find that the LLEV SNe II should not represent a severe contaminant in the use of normal SNe II as distance indicators with the PMM.
Notas
Tesis (Doctor en Astrofísica)
Palabras clave
Supernovas (Astronomía)