Search Publications
Investigating the Origin of X-Ray Jets: A Case Study of Four Hybrid Morphology MOJAVE Blazars
Baum, Stefi A.; O'Dea, Christopher P.; Marshall, Herman L. +3 more
We carried out Chandra, Hubble Space Telescope (HST), and Very Large Array observations of four MOJAVE blazars that have previously been classified as hybrid (FR I/II) blazars in terms of radio morphology but not total radio power. The motivation of this study is to determine the X-ray emission mechanism in jets, these being different in FR I and …
When Do Stars Go Boom?
Cohen, Roger E.; Sabbi, Elena; Caiazzo, Ilaria +10 more
The maximum mass of a star that can produce a white dwarf (WD) is an important astrophysical quantity. One of the best approaches to establishing this limit is to search for WDs in young star clusters in which only massive stars have had time to evolve and where the mass of the progenitor can be established from the cooling time of the WD together…
Imaging and Spectroscopic Observations of the Dynamic Processes in Limb Solar Flares
Ding, M. D.; Li, Y.; Song, De-Chao +2 more
We investigate various dynamic processes including magnetic reconnection, chromospheric evaporation, and coronal rain draining in two limb solar flares through imaging and spectroscopic observations from the Interface Region Imaging Spectrograph (IRIS) and the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory. In the early…
Discovery of a Brown Dwarf with Quasi-spherical Mass Loss
Dunham, Michael M.; Jofré, Paula; Cieza, Lucas A. +14 more
We report the serendipitous discovery of an elliptical shell of CO associated with the faint stellar object SSTc2d J163134.1-240060 as part of the "Ophiuchus Disk Survey Employing ALMA" (ODISEA), a project aiming to study the entire population of protoplanetary disks in the Ophiuchus Molecular Cloud from 230 GHz continuum emission and 12
A Semi-empirical Approach to the Dynamic Coupling of CMEs and Solar Wind
Riley, P.; Corona-Romero, P.; González-Avilés, J. J.
Coronal mass ejections (CMEs) are one of the most relevant phenomena for space weather. Moreover, CMEs can negatively affect essential services and facilities. Therefore, to protect society, we require well-grounded knowledge of the physics that governs the propagation of CMEs from near the Sun to the orbit of Earth. In this work, we deduce expres…
Magnetic Field Structure, Doppler Shift, and Intensity of Active Regions and Their Connections with the Solar Wind
Fu, Hui; Li, Bo; Xia, Lidong +4 more
The properties of active regions and their connections with the solar wind are important issues. In this study, nine isolated active regions near the solar disk center were chosen. The relationships between blueshift, intensity, magnetic concentrated areas (MCAs), and the potential-field source-surface (PFSS) open magnetic field of active regions …
Do All Low-Mass Stars Undergo Extra Mixing Processes?
Bania, T. M.; Balser, Dana S.; Wenger, Trey V.
Standard stellar evolution models that only consider convection as a physical process to mix material inside of stars predict the production of significant amounts of 3He in low-mass stars (M < 2 M ⊙), with peak abundances of 3He/H ~ few × 10-3 by number. Over the lifetime of the Galaxy, this ought to…
Using Computational Models to Uncover the Parameters of Three Kepler Binaries: KIC 5957123, KIC 8314879, and KIC 10727668
Odesse, Padraic E.; Lovekin, Catherine
Theories of stellar convective core overshoot can be examined through analysis of pulsating stars. Better accuracy can be achieved by obtaining external constraints such as those provided by observing pulsating stars in eclipsing binary systems, but this requires that the binary parameters be identified so photometric variations of the pulsating c…
Plasma Oscillations and Kinetic Instabilities at Ion Scales in the Expanding Magnetosheath
Trávníček, Pavel M.; Chaston, Chris C.
We investigate a relationship between a decaying spectrum of magnetic field perturbations and kinetic instabilities in a slowly expanding magnetosheath plasma using two-dimensional hybrid expanding simulations in (X, Y) space. We impose an initial ambient magnetic field B 0/B 0 = (1, 0, 0), and superimpose a flat spectrum of …
A Matched Survey for the Enigmatic Low Radio Frequency Transient ILT J225347+862146
Hallinan, Gregg; Sharma, Yashvi; Huang, Yuping +3 more
Discovered in 2011 with LOFAR, the 15 Jy low-frequency radio transient ILT J225347+862146 heralds a potentially prolific population of radio transients at <100 MHz. However, subsequent transient searches in similar parameter space yielded no detections. We test the hypothesis that these surveys at comparable sensitivity have missed the populati…