Search Publications
A Multiwavelength Analysis of the Halo Planetary Nebula DdDm-1
Dufour, R. J.; Henry, R. B. C.; Kwitter, K. B. +1 more
We present new HST optical imagery as well as new UV and IR spectroscopic data obtained with the Hubble Space Telescope and Spitzer Space Telescope, respectively, of the halo planetary nebula DdDm-1. For the first time we present a resolved image of this object, which indicates that the morphology of DdDm-1 can be described as two orthogonal ellip…
Ion Anisotropy and High-Energy Variability of Large Solar Particle Events: A Comparative Study
Reames, Donald V.; Tan, Lun C.; Ng, Chee K.
We have made comparative studies of ion anisotropy and high-energy variability of solar energetic particle (SEP) events previously examined by the Solar, Heliospheric, and Interplanetary Environment (SHINE) Workshop campaign. We have found distinctly different characteristics of SEPs in two large "gradual" events having very similar solar progenit…
Sequestration of Noble Gases by H+3 in Protoplanetary Disks and Outer Solar System Composition
Ceccarelli, C.; Mousis, O.; Pauzat, F. +1 more
We study the efficiency of the noble gas sequestration by the ion H+3 in the form of X H+3 complexes (with X = argon , krypton, or xenon) in gas-phase conditions similar to those encountered during the cooling of protoplanetary disks. We show that X H+3 complexes form very stable st…
The Nearby and Extremely Metal-poor Galaxy CGCG 269-049
Windhorst, Rogier A.; Kim, Hwihyun; Jansen, Rolf A. +2 more
We present Hubble Space Telescope (HST) and Spitzer Space Telescope images and photometry of the extremely metal-poor (Zcong 0.03 Z⊙) blue dwarf galaxy CGCG 269-049. The HST images reveal a large population of red giant and asymptotic giant branch stars, ruling out the possibility that the galaxy has recently formed. From the magnitude …
Observations of the Gas Reservoir around a Star-Forming Galaxy in the Early Universe
Broadhurst, Tom; Frye, Brenda L.; Bowen, David V. +8 more
We present a high signal-to-noise spectrum of a bright galaxy at z = 4.9 in 14 hr of integration on VLT FORS2. This galaxy is extremely bright, i850 = 23.10 +/- 0.01, and is strongly lensed by the foreground massive galaxy cluster A1689 (z = 0.18). Stellar continuum is seen longward of the Lyα emission line at ~7100 Å, while intergalact…
Explosive Events and the Evolution of the Photospheric Magnetic Field
Muglach, K.
Transition region explosive events have long been suggested as direct signatures of magnetic reconnection in the solar atmosphere. In seeking further observational evidence to support this interpretation, we study the relation between explosive events and the evolution of the solar magnetic field as seen in line-of-sight photospheric magnetograms.…
XMM-Newton Observations of IGR J00291+5934: Signs of a Thermal Spectral Component during Quiescence
Stella, Luigi; Campana, Sergio; D'Avanzo, Paolo +1 more
We present X-ray observations of the transient accretion-powered millisecond pulsar IGR J00291+5934 during quiescence. IGR J00291+5934 is the first source among accretion-powered millisecond pulsars to show signs of a thermal component in its quiescent spectrum. Fitting this component with a neutron star atmosphere or a blackbody model we obtain s…
Bayesian Analysis of Solar Oscillations
Kucera, T.; Marsh, M. S.; Ireland, J.
A Bayesian probability-based approach is applied to the problem of detecting and parameterizing oscillations in the upper solar atmosphere for the first time. Due to its statistical origin, this method provides a mechanism for determining the number of oscillations present, gives precise estimates of the oscillation parameters with a self-consiste…
Transition Region Velocity Oscillations Observed by EUNIS-06
Mathioudakis, M.; Keenan, F. P.; Jess, D. B. +3 more
Spectroscopic measurements of NOAA AR 10871, obtained with the Extreme Ultraviolet Normal Incidence Spectrograph (EUNIS) sounding rocket instrument on 2006 April 12, reveal velocity oscillations in the He II 303.8 Å emission line formed at T ≈ 5 × 104 K. The oscillations appear to arise in a bright active region loop arcade about 25
In Search of the Largest Velocity Dispersion Galaxies
Shields, G. A.; Gebhardt, K.; Bernardi, M. +2 more
We present Hobby-Eberly Telescope (HET) observations for galaxies at redshift z < 0.3 from the Sloan Digital Sky Survey (SDSS) showing large velocity dispersions while appearing to be single galaxies in HST images. The high signal-to-noise HET spectra provide more definitive velocity dispersions. The maximum velocity dispersion we find is σ