Search Publications
Molecular Gas in Young Debris Disks
Apai, D.; Pascucci, I.; Ábrahám, P. +7 more
Gas-rich primordial disks and tenuous gas-poor debris disks are usually considered as two distinct evolutionary phases of the circumstellar matter. Interestingly, the debris disk around the young main-sequence star 49 Ceti possesses a substantial amount of molecular gas and possibly represents the missing link between the two phases. Motivated to …
Observation of High-speed Outflow on Plume-like Structures of the Quiet Sun and Coronal Holes with Solar Dynamics Observatory/Atmospheric Imaging Assembly
He, Jiansen; Habbal, Shadia Rifai; McIntosh, Scott W. +1 more
Observations from the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory reveal ubiquitous episodic outflows (jets) with an average speed around 120 km s-1 at temperatures often exceeding a million degree in plume-like structures, rooted in magnetized regions of the quiet solar atmosphere. These outflows are not restric…
A Combined Low-radio Frequency/X-ray Study of Galaxy Groups. I. Giant Metrewave Radio Telescope Observations at 235 MHz AND 610 MHz
Raychaudhury, Somak; Jones, Christine; Clarke, Tracy E. +12 more
We present new Giant Metrewave Radio Telescope observations at 235 MHz and 610 MHz of 18 X-ray bright galaxy groups. These observations are part of an extended project, presented here and in future papers, which combines low-frequency radio and X-ray data to investigate the interaction between central active galactic nuclei (AGNs) and the intra-gr…
A Comparative Study of Confined and Eruptive Flares in NOAA AR 10720
Cheng, X.; Ding, M. D.; Zhang, J. +2 more
We investigate the distinct properties of two types of flares: eruptive flares associated with coronal mass ejections (CMEs) and confined flares without CMEs. Our study sample includes nine M- and X-class flares, all from the same active region (AR), six of which are confined and three others which are eruptive. The confined flares tend to be more…
Variations in the Axisymmetric Transport of Magnetic Elements on the Sun: 1996-2010
Hathaway, David H.; Rightmire, Lisa
We measure the axisymmetric transport of magnetic flux on the Sun by cross-correlating narrow strips of data from line-of-sight magnetograms obtained at a 96 minute cadence by the MDI instrument on the ESA/NASA SOHO spacecraft and then averaging the flow measurements over each synodic rotation of the Sun. Our measurements indicate that the axisymm…
Formation of Dust in the Ejecta of Type Ia Supernovae
Nomoto, Ken'ichi; Maeda, Keiichi; Tanaka, Masaomi +3 more
We investigate the formation of dust grains in the ejecta of Type Ia supernovae (SNe Ia), adopting the carbon-deflagration W7 model. In the calculations of dust formation, we apply the nucleation and grain growth theory and consider the two extreme cases of the formation of CO and SiO molecules: complete formation and no formation. The results of …
Near-ultraviolet Excess in Slowly Accreting T Tauri Stars: Limits Imposed by Chromospheric Emission
Edwards, Suzan; Brown, Alexander; France, Kevin +20 more
Young stars surrounded by disks with very low mass accretion rates are likely in the final stages of inner disk evolution and therefore particularly interesting to study. We present ultraviolet (UV) observations of the ~5-9 Myr old stars RECX-1 and RECX-11, obtained with the Cosmic Origins Spectrograph and Space Telescope Imaging Spectrograph on t…
Quasi-stellar Object Selection Algorithm Using Time Variability and Machine Learning: Selection of 1620 Quasi-stellar Object Candidates from MACHO Large Magellanic Cloud Database
Trichas, Markos; Alcock, Charles; Kim, Dae-Won +3 more
We present a new quasi-stellar object (QSO) selection algorithm using a Support Vector Machine, a supervised classification method, on a set of extracted time series features including period, amplitude, color, and autocorrelation value. We train a model that separates QSOs from variable stars, non-variable stars, and microlensing events using 58 …
Solar Source and Heliospheric Consequences of the 2010 April 3 Coronal Mass Ejection: A Comprehensive View
Bale, Stuart D.; Liu, Ying; Luhmann, Janet G. +1 more
We study the solar source and heliospheric consequences of the 2010 April 3 coronal mass ejection (CME) in the frame of the Sun-Earth connection using observations from a fleet of spacecraft. The CME is accompanied by a B7.4 long-duration flare, dramatic coronal dimming, and EUV waves. It causes significant heliospheric consequences and space weat…
Detailed Fit of "Critical Balance" Theory to Solar Wind Turbulence Measurements
Wicks, Robert T.; Horbury, Timothy S.; Forman, Miriam A.
We derive the reduced spectrum of turbulent magnetic fluctuations at different frequencies f which would be observed by a single spacecraft in the solar wind when the magnetic field was at an angle θ B to the solar wind flow, if the wavevector spectrum in the solar wind frame were in anisotropic "critical balance" (CB) as proposed by Go…