We present a comparative seismic study of conditions around and beneath isolated sunspots. Using the European Grid of Solar Observations' Solar Feature Catalogue of sunspots derived from SOHO/MDI continuum and magnetogram data, 1996-2005, we identify a set of isolated sunspots by checking that within a Carrington Rotation there were no other spots detected in the vicinity. We then use level-2 tracked MDI Dopplergrams available from SOHO website to investigate wave-speed perturbations of such sunspots using time-distance helioseismology.
@article{arxiv.0802.2524,
title = {Time Distance Study of Isolated Sunspots},
author = {S. Zharkov and C. Nicholas and M. J. Thompson},
journal= {arXiv preprint arXiv:0802.2524},
year = {2009}
}