[Doctorandos] Hoy 14:00hs - Charla del Dr. A. Cikota - Salón Meridiano

[Secretaría de Ciencia y Técnica]

A toda la comunidad:

Les recordamos que en el día de hoy, a las 14:00 hs. en el Salón 
Meridiano, se llevará a cabo una charla a cargo del Dr.  Aleksandar 
Cikota del European Southern Observatory, Chile.

*
**Quedan todos cordialmente invitados.**

**Atentamente,

Secyt-FCAG**
*


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Estimadas/os colegas,

la semana que viene estará de visita en La Plata el Dr.  Aleksandar 
Cikota del European Southern Observatory, Chile. El día martes 31 de 
mayo dará una charla sobre su tema de investigación, por lo cual los/as 
invitamos a asistir en modo presencial. La misma tendrá lugar en el 
Salón Meridiano de la FCAG, y se deberá mantener un aforodel 50%, y el 
uso de barbijo. La charla será dada en inglés. Abajo encontrarán el 
título y resumen.

Les dejo además el contacto de Aleksandar (aleksandar.cikota en eso.org) y 
de Natalia por cualquier duda o consulta 
(natalialrossignoli en gmail.com). Quedan todos/as invitados/as.


Dr. Favio R. Faifer
Director
Instituto de Astrofísica de La Plata
CONICET-UNLP

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Investigating Type Ia Supernovae with (spectro)polarimetry

Abstract: Spectropolarimetry offers an independent method to the study 
inter/circum-stellar dust properties (by observing the continuum 
polarization) and the analysis of the three-dimensional geometrical 
properties of unresolved sources (by observing the intrinsic continuum 
polarization and line polarization).
I will discuss the results from a statistical analysis of the Si II line 
polarization measurements of a sample of ~35 SNe Ia, and argue possible 
implications on the progenitor system. We reduced and examined, in a 
systematic way, archival linear spectropolarimetric data of a sample of 
35 SNe Ia observed with the VLT’s FORS1+2 between 2001 and 2015 at 127 
epochs in total (Cikota et al. 2019).
We found a statistically significant linear relationship between the 
polarization of the Si II 6355Å line before maximum brightness and the 
Si II line velocity and suggest that this, along with the Dm15–PSi II 
relationship, may be explained in the context of a delayed-detonation 
model. In contrast, we compared our observations to numerical 
predictions in the Dm15–vSi II plane and found a dichotomy in the 
polarization properties between Chandrasekhar and sub-Chandrasekhar mass 
explosions, which supports the possibility of two distinct explosion 
mechanisms.
Furthermore, we acquired imaging polarimetry of a statistical sample of 
68 SNe Ia in host galaxies of different morphological types, and found 
that the source of the peculiar polarization curves steeply rising 
towards blue wavelengths (and the peculiar extinction curves with low Rv 
values) observed towards some reddened SNe Ia is likely the result of 
interstellar material as opposed to circumstellar material. Thus, the 
peculiar polarization and extinction properties observed toward some SNe 
Ia may be explained by the radiative torque disruption mechanism induced 
by the SN or the interstellar radiation field (Chu et al. 2022).

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