Kerry Kuehn

Volume 1 (c2015) The heavens and the earth -- Nature, number and substance -- The shape and motion of the heavens -- Harmony and complexity -- Earth at the center of the world -- The world of Ptolemy -- Measuring the tropical Year -- Geometrical tools -- The sun, the moon and the calendar -- From Astronomy to cartography -- Climates and continents -- Heliocentrism: hypothesis or truth? -- Earth as a wandering star -- Re-ordering the heavenly spheres -- Celestial physics -- Broken spheres -- Kepler's third law -- Kepler's first and second laws -- Mountains on the moon -- The Medician stars -- The luminosity of variable stars -- Galactic spectra -- Measuring astronomical distances -- A new theory of gravity -- Euclid, Gauss and Mercury's orbit -- A finite universe with no boundary -- The structure of the universe -- Measuring the potentially infinite -- The birth of the Big Bang -- The primeval atom.

© 2016. The American Astronomical Society. All rights reserved.We present DES14X3taz, a new hydrogen-poor superluminous supernova discovered by the Dark Energy Survey supernova program, with additional photometric data provided by the Survey Using DECam for Superluminous Supernovae. Spectra obtained using Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy on the Gran Telescopio CANARIAS show DES14X3taz is an SLSN-I at z = 0.608. Multi-color photometry reveals a double-peaked light curve: a blue and relatively bright initial peak that fades rapidly prior to the slower rise of the main light curve. Our multi-color photometry allows us, for the first time, to show that the initial peak cools from 22,000 to 8000 K over 15 rest-frame days, and is faster and brighter than any published core-collapse supernova, reaching 30% of the bolometric luminosity of the main peak. No physical 56Ni-powered model can fit this initial peak. We show that a shock-cooling model followed by a magnetar driving the second phase of the light curve can adequately explain the entire light curve of DES14X3taz. Models involving the shock-cooling of extended circumstellar material at a distance of ≃400 R⊙ are preferred over the cooling of shock-heated surface layers of a stellar envelope. We compare DES14X3taz to the few double-peaked SLSN-I events in the literature. Although the rise times and characteristics of these initial peaks differ, there exists the tantalizing possibility that they can be explained by one physical interpretation.