Donald W. Jackson on Prisoners of America’s Wars: From the Early Republic to Guantanamo. By Stephanie Carvin. New York: Columbia University Press, 2010. 336pp.

A review of: Prisoners of America’s Wars: From the Early Republic to Guantanamo. By Stephanie Carvin. New York: Columbia University Press, 2010. 336pp

Donald W. Jackson on Who Governs the Globe? Edited by Deborah D. Avant, Martha Finnemore, and Susan K. Sell. New York: Cambridge University Press, 2010. 433pp.

A review of: Who Governs the Globe? Edited by Deborah D. Avant, Martha Finnemore, and Susan K. Sell. New York: Cambridge University Press, 2010. 433pp

Recent Transits of the Super-Earth Exoplanet GJ 1214b

We report recent ground-based photometry of the transiting super-Earth exoplanet GJ1214b at several wavelengths, including the infrared near 1.25 microns (J-band). We observed a J-band transit with the FLAMINGOS infrared imager and the 2.1-meter telescope on Kitt Peak, and we observed several optical transits using a 0.5-meter telescope on Kitt Peak and the 0.36-meter Universidad de Monterrey Observatory telescope. Our high-precision J-band observations exploit the brightness of the M-dwarf host star at this infrared wavelength as compared to the optical, as well as being significantly less affected by stellar activity and limb darkening. We fit the J-band transit to obtain an independent determination of the planetary and stellar radii. Our radius for the planet (2.61^+0.30_-0.11 Earth radii) is in excellent agreement with the discovery value reported by Charbonneau et al. based on optical data. We demonstrate that the planetary radius is insensitive to degeneracies in the fitting process. We use all of our observations to improve the transit ephemeris, finding P=1.5804043 +/- 0.0000005 days, and T0=2454964.94390 +/- 0.00006 BJD.Comment: Accepted for ApJ Letters, 7 pages, 3 Figures, 2 Table

Spectral Bandwidth Reduction of Thomson Scattered Light by Pulse Chirping

Based on single particle tracking in the framework of classical Thomson scattering with incoherent superposition, we developed a fully relativistic, three dimensional numerical code that calculates and quantifies the characteristics of emitted radiation when a relativistic electron beam collides head-on with a focused counter-propagating intense laser field. The developed code has been benchmarked against analytical expressions, based on the plane wave approximation to the laser field, derived in (1). For sufficiently long duration laser pulses, we find that the scattered radiation spectrum is broadened due to interferences arising from the pulsed nature of the laser. We show that by appropriately chirping the scattering laser pulse, the spectral broadening could be minimized.Comment: 11 pages, 3 figures, 25 reference