Search Publications
Acceleration in Fast Halo CMEs and Synchronized Flare HXR Bursts
Temmer, M.; Veronig, A. M.; Maričić, D. +4 more
We study two well-observed, fast halo CMEs, covering the full CME kinematics including the initiation and impulsive acceleration phase, and their associated flares. We find a close synchronization between the CME acceleration profile and the flare energy release as indicated by the RHESSI hard X-ray flux onsets, as well as peaks occur simultaneous…
The Very Low Albedo of an Extrasolar Planet: MOST Space-based Photometry of HD 209458
Moffat, Anthony F. J.; Rucinski, Slavek M.; Seager, Sara +8 more
Measuring the albedo of an extrasolar planet provides insight into its atmospheric composition and its global thermal properties, including heat dissipation and weather patterns. Such a measurement requires very precise photometry of a transiting system, fully sampling many phases of the secondary eclipse. Space-based optical photometry of the tra…
Stellar Proper Motions in the Galactic Bulge from Deep Hubble Space Telescope ACS WFC Photometry
Brown, Thomas M.; Casertano, Stefano; Smith, T. Ed +11 more
We present stellar proper motions in the Galactic bulge from the Sagittarius Window Eclipsing Extrasolar Search (SWEEPS) project using ACS WFC on HST. Proper motions are extracted for more than 180,000 objects, with >81,000 measured to accuracy better than 0.3 mas yr-1 in both coordinates. We report several results based on these mea…
The Magnetic Landscape of the Sun's Polar Region
Lites, B. W.; Ichimoto, K.; Tsuneta, S. +11 more
We present observations of the magnetic landscape of the polar region of the Sun that are unprecedented in terms of spatial resolution, field of view, and polarimetric precision. They were carried out with the Solar Optical Telescope aboard Hinode. Using a Milne-Eddington inversion, we find many vertically oriented magnetic flux tubes with field s…
Giant Chromospheric Anemone Jet Observed with Hinode and Comparison with Magnetohydrodynamic Simulations: Evidence of Propagating Alfvén Waves and Magnetic Reconnection
Shibata, K.; Katsukawa, Y.; Okamoto, T. J. +4 more
Hinode discovered a beautiful giant jet with both cool and hot components at the solar limb on 2007 February 9. Simultaneous observations by the Hinode SOT, XRT, and TRACE 195 Å satellites revealed that hot (~5 × 106 K) and cool (~104 K) jets were located side by side and that the hot jet preceded the associated cool jet (~1-…
The Sloan Lens ACS Survey. VI. Discovery and Analysis of a Double Einstein Ring
Treu, Tommaso; Gavazzi, Raphaël; Marshall, Philip J. +4 more
We report the discovery of two concentric Einstein rings around the gravitational lens SDSS J0946+1006. The main lens is at redshift zl = 0.222, while the inner ring (1) is at redshift zs1 = 0.609 (REin 1 = 1.43'' +/- 0.01''). The wider image separation (REin 2 = 2.07''+/- 0.02'') of the outer ring (2) i…
Solar Surface Emerging Flux Regions: A Comparative Study of Radiative MHD Modeling and Hinode SOT Observations
Cheung, M. C. M.; Tarbell, T. D.; Title, A. M. +1 more
We present results from numerical modeling of emerging flux regions on the solar surface. The modeling was carried out by means of three-dimensional (3D) radiative MHD simulations of the rise of buoyant magnetic flux tubes through the convection zone and into the photosphere. Due to the strong stratification of the convection zone, the rise result…
Multiple Stellar Populations in Three Rich Large Magellanic Cloud Star Clusters
Mackey, A. D.; Ferguson, A. M. N.; Broby Nielsen, P. +1 more
We present deep color-magnitude diagrams for three rich intermediate-age star clusters in the LMC, constructed from archival ACS F435W and F814W imaging. All three clusters exhibit clear evidence for peculiar main-sequence turnoffs. NGC 1846 and 1806 each possess two distinct turnoff branches, while the turnoff for NGC 1783 shows a much larger spr…
The Current Sheet Associated with the 2003 November 4 Coronal Mass Ejection: Density, Temperature, Thickness, and Line Width
Raymond, J. C.; Ciaravella, A.
In the wake of the 2003 November 4 coronal mass ejection associated with the largest solar flare of the last sunspot cycle, a current sheet (CS) was observed by the Ultraviolet Coronagraph Spectrometer (UVCS) as a narrow bright feature in the [Fe XVIII] (106.8 K) line. This is the first UV observation in which the CS evolution is follow…
An Explanation for the Observed Weak Size Evolution of Disk Galaxies
Bell, Eric F.; Somerville, Rachel S.; Wisotzki, Lutz +14 more
Surveys of distant galaxies with the Hubble Space Telescope and from the ground have shown that there is only mild evolution in the relationship between radial size and stellar mass for galactic disks from z ~ 1 to the present day. Using a sample of nearby disk-dominated galaxies from the Sloan Digital Sky Survey (SDSS) and high-redshift data from…