Evidence for asymmetric distribution of circumstellar material around type Ia supernovae

Francisco Förster, Santiago González-Gaitán, Joseph Anderson, Sebastián Marchi, Claudia Gutiérrez, Mario Hamuy, Giuliano Pignata, Régis Cartier

Resultado de la investigación: Article

10 Citas (Scopus)

Resumen

We study the properties of low-velocity material in the line of sight toward nearby Type Ia supernovae (SNe Ia) that have measured late phase nebular velocity shifts (v neb), thought to be an environment-independent observable. We have found that the distribution of equivalent widths of narrow blended Na I D1 and D2 and Ca II H and K absorption lines differs significantly between those SNe Ia with negative and positive v neb, with generally stronger absorption for SNe Ia with v neb ≥ 0. A similar result had been found previously for the distribution of colors of SNe Ia, which was interpreted as a dependence of the temperature of the ejecta with viewing angle. Our work suggests that (1) a significant part of these differences in color should be attributed to extinction, (2) this extinction is caused by an asymmetric distribution of circumstellar material (CSM), and (3) the CSM absorption is generally stronger on the side of the ejecta opposite to where the ignition occurs. Since it is difficult to explain (3) via any known physical processes that occur before explosion, we argue that the asymmetry of the CSM is originated after explosion by a stronger ionizing flux on the side of the ejecta where ignition occurs, probably due to a stronger shock breakout and/or more exposed radioactive material on one side of the ejecta. This result has important implications for both progenitor and explosion models.

Idioma originalEnglish
Número de artículoL21
PublicaciónAstrophysical Journal Letters
Volumen754
N.º2
DOI
EstadoPublished - 1 ago 2012

Huella dactilar

ejecta
supernovae
explosions
explosion
ignition
extinction
material absorption
color
radioactive materials
phase velocity
line of sight
low speed
shock
asymmetry
distribution
material
shift
temperature

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Citar esto

Förster, F., González-Gaitán, S., Anderson, J., Marchi, S., Gutiérrez, C., Hamuy, M., ... Cartier, R. (2012). Evidence for asymmetric distribution of circumstellar material around type Ia supernovae. Astrophysical Journal Letters, 754(2), [L21]. https://doi.org/10.1088/2041-8205/754/2/L21
Förster, Francisco ; González-Gaitán, Santiago ; Anderson, Joseph ; Marchi, Sebastián ; Gutiérrez, Claudia ; Hamuy, Mario ; Pignata, Giuliano ; Cartier, Régis. / Evidence for asymmetric distribution of circumstellar material around type Ia supernovae. En: Astrophysical Journal Letters. 2012 ; Vol. 754, N.º 2.
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Förster, F, González-Gaitán, S, Anderson, J, Marchi, S, Gutiérrez, C, Hamuy, M, Pignata, G & Cartier, R 2012, 'Evidence for asymmetric distribution of circumstellar material around type Ia supernovae', Astrophysical Journal Letters, vol. 754, n.º 2, L21. https://doi.org/10.1088/2041-8205/754/2/L21

Evidence for asymmetric distribution of circumstellar material around type Ia supernovae. / Förster, Francisco; González-Gaitán, Santiago; Anderson, Joseph; Marchi, Sebastián; Gutiérrez, Claudia; Hamuy, Mario; Pignata, Giuliano; Cartier, Régis.

En: Astrophysical Journal Letters, Vol. 754, N.º 2, L21, 01.08.2012.

Resultado de la investigación: Article

TY - JOUR

T1 - Evidence for asymmetric distribution of circumstellar material around type Ia supernovae

AU - Förster, Francisco

AU - González-Gaitán, Santiago

AU - Anderson, Joseph

AU - Marchi, Sebastián

AU - Gutiérrez, Claudia

AU - Hamuy, Mario

AU - Pignata, Giuliano

AU - Cartier, Régis

PY - 2012/8/1

Y1 - 2012/8/1

N2 - We study the properties of low-velocity material in the line of sight toward nearby Type Ia supernovae (SNe Ia) that have measured late phase nebular velocity shifts (v neb), thought to be an environment-independent observable. We have found that the distribution of equivalent widths of narrow blended Na I D1 and D2 and Ca II H and K absorption lines differs significantly between those SNe Ia with negative and positive v neb, with generally stronger absorption for SNe Ia with v neb ≥ 0. A similar result had been found previously for the distribution of colors of SNe Ia, which was interpreted as a dependence of the temperature of the ejecta with viewing angle. Our work suggests that (1) a significant part of these differences in color should be attributed to extinction, (2) this extinction is caused by an asymmetric distribution of circumstellar material (CSM), and (3) the CSM absorption is generally stronger on the side of the ejecta opposite to where the ignition occurs. Since it is difficult to explain (3) via any known physical processes that occur before explosion, we argue that the asymmetry of the CSM is originated after explosion by a stronger ionizing flux on the side of the ejecta where ignition occurs, probably due to a stronger shock breakout and/or more exposed radioactive material on one side of the ejecta. This result has important implications for both progenitor and explosion models.

AB - We study the properties of low-velocity material in the line of sight toward nearby Type Ia supernovae (SNe Ia) that have measured late phase nebular velocity shifts (v neb), thought to be an environment-independent observable. We have found that the distribution of equivalent widths of narrow blended Na I D1 and D2 and Ca II H and K absorption lines differs significantly between those SNe Ia with negative and positive v neb, with generally stronger absorption for SNe Ia with v neb ≥ 0. A similar result had been found previously for the distribution of colors of SNe Ia, which was interpreted as a dependence of the temperature of the ejecta with viewing angle. Our work suggests that (1) a significant part of these differences in color should be attributed to extinction, (2) this extinction is caused by an asymmetric distribution of circumstellar material (CSM), and (3) the CSM absorption is generally stronger on the side of the ejecta opposite to where the ignition occurs. Since it is difficult to explain (3) via any known physical processes that occur before explosion, we argue that the asymmetry of the CSM is originated after explosion by a stronger ionizing flux on the side of the ejecta where ignition occurs, probably due to a stronger shock breakout and/or more exposed radioactive material on one side of the ejecta. This result has important implications for both progenitor and explosion models.

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Förster F, González-Gaitán S, Anderson J, Marchi S, Gutiérrez C, Hamuy M y otros. Evidence for asymmetric distribution of circumstellar material around type Ia supernovae. Astrophysical Journal Letters. 2012 ago 1;754(2). L21. https://doi.org/10.1088/2041-8205/754/2/L21