Search Publications
Coronal Heating by Surface Alfvén Wave Damping: Implementation in a Global Magnetohydrodynamics Model of the Solar Wind
Gombosi, T. I.; Frazin, R.; Sokolov, I. V. +5 more
The heating and acceleration of the solar wind is an active area of research. Alfvén waves, because of their ability to accelerate and heat the plasma, are a likely candidate in both processes. Many models have explored wave dissipation mechanisms which act either in closed or open magnetic field regions. In this work, we emphasize the boundary be…
Observing planet-disk interaction in debris disks
Ertel, S.; Wolf, S.; Rodmann, J.
Context. Debris disks are commonly considered to be a by-product of planet formation. Structures in debris disks induced by planet-disk interaction are promising to provide valuable constraints on the existence and properties of embedded planets.
Aims: We investigate the observability of structures in debris disks induced by planet-disk inter…
Sunspot Rotation, Sigmoidal Filament, Flare, and Coronal Mass Ejection: The Event on 2000 February 10
Yan, X. L.; Kong, D. F.; Qu, Z. Q. +1 more
We find that a sunspot with positive polarity had an obvious counterclockwise rotation and resulted in the formation and eruption of an inverse S-shaped filament in NOAA Active Region 08858 from 2000 February 9 to 10. The sunspot had two umbrae which rotated around each other by 195° within about 24 hr. The average rotation rate was nearly 8° hr
Estimating Travel Times of Coronal Mass Ejections to 1 AU Using Multi-spacecraft Coronagraph Data
Mierla, M.; Zhukov, A. N.; Rodriguez, L. +3 more
We study the relationship between the speeds of coronal mass ejections (CMEs) obtained close to the Sun and in the interplanetary medium during the low solar-activity period from 2008 to 2010. We use a multi-spacecraft forward-modeling technique to fit a flux-rope-like model to white-light coronagraph images from the STEREO and SOHO spacecraft to …
Spectroscopy of novae -- a user's manual
Shore, Steven N.
The spectroscopic development of classical novae is described as a narrative of the various stages of the outburst. The review highlights the multiwavelength aspects of the phenomenology and the recent developments related to structure, inhomogeneity, and dynamics of the ejecta. Special emphasis is placed on the distinct behavior of the symbiotic-…
On the Significance of Absorption Features in HST/COS Data
Danforth, Charles W.; France, Kevin; Stocke, John T. +2 more
We present empirical scaling relations for the significance of absorption features detected in medium-resolution, far-UV spectra obtained with the Cosmic Origins Spectrograph (COS). These relations properly account for both the extended wings of the COS line-spread function and the non-Poissonian noise properties of the data, which we characterize…
Warm Gas in the Virgo Cluster. I. Distribution of Lyα Absorbers
Chen, Hsiao-Wen; Yoon, Joo Heon; Putman, Mary E. +2 more
The first systematic study of the warm gas (T = 104 - 5 K) distribution across a galaxy cluster is presented using multiple background QSOs in and around the Virgo Cluster. We detect 25 Lyα absorbers (NH I = 1013.1-15.4 cm-2) in the Virgo velocity range toward 9 of 12 QSO sightlines observed with the Co…
The Star Formation History of M32
Monachesi, Antonela; Lauer, Tod R.; Dressler, Alan +5 more
We use deep Hubble Space Telescope Advanced Camera for Surveys/High Resolution Channel observations of a field within M32 (F1) and an M31 background field (F2) to determine the star formation history (SFH) of M32 from its resolved stellar population. We find that 2-5 Gyr old stars contribute ~40% ± 17% of M32's mass, while ~55% ± 21% of M32's mass…
CLASH: Discovery of a Bright z ~= 6.2 Dwarf Galaxy Quadruply Lensed by MACS J0329.6-0211
Shu, X.; Zheng, W.; Molino, A. +22 more
We report the discovery of a z phot = 6.18+0.05 - 0.07 (95% confidence level) dwarf galaxy, lensed into four images by the galaxy cluster MACS J0329.6-0211 (zl = 0.45). The galaxy is observed as a high-redshift dropout in HST/ACS/WFC3 CLASH and Spitzer/IRAC imaging. Its redshift is securely determined du…
Weak-lensing Results for the Merging Cluster A1758
Bradač, M.; Markevitch, M.; Gonzalez, A. H. +2 more
Here we present the weak-lensing results for A1758, which is known to consist of four subclusters undergoing two separate mergers, A1758N and A1758S. Weak-lensing results for A1758N agree with previous weak-lensing results for clusters 1E0657-558 (Bullet cluster) and MACS J0025.4-1222, whose X-ray gas components were found to be largely separated …