POSTER PAPER 8.07
The Radio Corona of AR Lacertae: Flaring and Quiescent Emission
Trigilio, C., Buemi, C.S., Umana, G., Leto, P., Rodono, M., Pagano, I.
Institute: Istituto di Radioastronomia del CNR, Italy
Institute: Osservatorio Astrofisico di Catania, Italy
Institute: Dipartimento di Fisica e Astronomia, Universita di Catania, Italy
Contact Email: trigilio@ira.noto.cnr.it
Abstract:
A multiwavelength observing campaign on the binary system AR Lacertae was
performed over a time interval of four days. During this period the source
showed a main flare event, followed by an enanched but decreasing flux level.
The five-frequencies VLA and the simultaneous high spatial resolution
VLBA data at two frequencies
allow us to study the evolution of the structure of
the radio emitting regions and of the spectra during the
flare, as well as outside the flare event.
During the quiescence, the negative spectral index indicates that the radio
source is optically thin. As the flare starts, the spectra becomes quite flat,
suggesting that the source cannot be associated to a single homogeneous
region, but to a complex coronal structure.
The double source revealed by the analysis of the VLBA data confirms the
enhanced complexity of the emitting region during the flare.
Index Keywords: AR Lacertae; VLA; VLBA
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Manuscript submitted: 2001-Sep-06
"The Future of Cool-Star Astrophysics", 2003, Eds. A. Brown,
G. M. Harper, & T. R. Ayres.
Proceedings of 12th Cambridge Workshop on Cool Stars, Stellar Systems,
& The Sun,
© 2003 University of Colorado.