Anomalous Polarization Profiles in Sunspots: Possible Origin of Umbral Flashes
H. Socas-Navarro,
1
J. Trujillo Beuno,
B. Ruiz
Cobo
13
We present time-series spectropolarimetric
observations of sunspots in the Ca II infrared triplet lines,
which show a periodic occurrence of anomalous, asymmetric, circular
polarization profiles in the umbral chromosphere. The profiles may be
caused by the periodic development of an unresolved atmospheric
component in a downward flowing magnetized environment. This active
component with upward directed velocities as high as 10 kilometers per
second is connected to the umbral flash (UF) phenomenon. We can explain the observations with a semiempirical model of the chromospheric oscillation and of the sunspot magnetized atmospheric plasma during a
UF event.
1 Instituto de Astrofísica de Canarias, E-38200
La Laguna, Tenerife, Spain.
2 Consejo Superior de
Investigaciones Científicas, Spain.
3 Departamento
de Astrofísica, Universidad de La Laguna, Tenerife, Spain.
