We present time-distance analyses of several active regions and a region of quiet Sun observed with the Global Oscillation Network Group (GONG). Analyzing temporal correlations between the p-mode oscillation signal observed within the sunspots with the signals integrated within surrounding annuli, we connrm the recent nding of Duvall and his colleagues that travel times (+) for outward propagat...

Because of the lack of reliable sunspot observation, the quality of sunspot number series is poor in the late 18th century, leading to the abnormally long solar cycle (1784–1799) before the Dalton minimum. Using the newly recovered solar drawings by the 18–19th century observers Staudacher and Hamilton, we construct the solar butterfly diagram, i.e. the latitudinal distribution of sunspots in t...

The presence of fine structures in the sunspot vector magnetic fields has been confirmed from Hinode as well as other earlier observations. We studied 43 sunspots based on the data sets taken from ASP/DLSP, Hinode (SOT/SP) and SVM (USO). In this Letter, (i) We introduce the concept of signed shear angle (SSA) for sunspots and establish its importance for non force-free fields. (ii) We find that...

Independent of the normal solar cycle, a decrease in the sunspot magnetic field strength has been observed using the Zeeman-split 1564.8nm Fe I spectral line at the NSO Kitt Peak McMath-Pierce telescope. Corresponding changes in sunspot brightness and the strength of molecular absorption lines were also seen. This trend was seen to continue in observations of the first sunspots of the new solar...

This paper explores the role of portfolio constraints in generating multiplicity of equilibrium. We present a simple asset market economy with two goods and two households, households who face constraints on their ability to take unbounded positions in risky stocks. Absent such constraints, equilibrium allocation is unique and is Pareto efficient. With a single portfolio constraint in place, th...