UBVRI Light curves of 44 Type Ia supernovae

We present UBVRI photometry of 44 Type la supernovae (SNe la) observed from 1997 to 2001 as part of a continuing monitoring campaign at the Fred Lawrence Whipple Observatory of the Harvard-Smithsonian Center for Astrophysics. The data set comprises 2190 observations and is the largest homogeneously observed and reduced sample of SNe la to date, nearly doubling the number of well-observed, nearby SNe la with published multicolor CCD light curves. The large sample of [U-band photometry is a unique addition, with important connections to SNe la observed at high redshift. The decline rate of SN la U-band light curves correlates well with the decline rate in other bands, as does the U - B color at maximum light. However, the U-band peak magnitudes show an increased dispersion relative to other bands even after accounting for extinction and decline rate, amounting to an additional ∼40% intrinsic scatter compared to the B band

SOFT X-RAY IMAGES OF THE SOLAR CORONA USING NORMAL INCIDENCE OPTICS

A solar coronal loop system has been photographed in soft X-rays using a normal incidence telescope based on multilayer mirror technology. The telescope consisted of a spherical objective rnirror of 4 cm aperture and 1 m focal length, a film cassette, and a focal plane shutter. A metallized thin plastic film filter was used to exclude visible light. The objective mirror was covered with a multilayer coating consisting of alternating layers of tungsten and carbon whose combined thicknesses satisfied the Bragg diffraction condition for 44 Ã... radiation The image was recorded during a rocket flight on 1985 October 25, and was dominated by emission lines arising from the Si XII spectrum. The rocket also carried a high resolution soft X-ray spectrograph that confirmed the presence of Si XII line radiation in the source. This image represents the first successful use of multilayer technology for astrophysical observations

Treating anxiety in early life

Anxiety disorders in pre-adolescence are probably the most common serious disorder of childhood, affecting around 1 in 30 British children. These conditions are chronic, distressing and impairing, and are treatable, but we are currently doing a poor job of serving these children

Fluorescence in Astrophysical Plasmas

Following the initial detection by Bowen in 1934 of the strong O III linesbeing due to accidental resonance with strong He II radiation, many strong spectralemission lines are explained as produced by fluorescence. Many of these areFe II lines pumped by H Lyα, as a consequence of strong radiation from hydrogenand a favorable energy level structure for Fe II. The lines are observed in manytypes of objects with low density plasma components. The Weigelt condensationsin the vicinity of the massive star Eta Carinae is one location where these lines areobserved and can be studied in detail, as well as been used for diagnostics.These gas condensations do not only show a spectrum indicating a nonequilibriumexcitation but also non-equilibrium ionization, where the strong hydrogenradiation plays a key role. Early studies identified certain strong lines beingthe result of Resonance Enhanced Two-Photon Ionization (RETPI). Further investigationssuggest that RETPI can be the responsible mechanism for the ionizationstructure of gas condensation.We will review the resonance processes, with emphasis on the Eta Carinae spectrum.Large spectral, spatial and temporal coverage is available for this fascinatingobject, allowing for detailed analysis