Search Publications
Resolving Ionization and Metallicity on Parsec Scales across Mrk 71 with HST-WFC3
Aloisi, Alessandra; James, Bethan L.; Calzetti, Daniela +2 more
Blue compact dwarf (BCD) galaxies in the nearby universe provide a means for studying feedback mechanisms and star formation processes in low-metallicity environments in great detail. Owing to their vicinity, these local analogs to primordial young galaxies are well suited for high-resolution studies that are unfeasible for high-redshift galaxies.…
Prediction of Geomagnetic Storm Strength from Inner Heliospheric In Situ Observations
Feng, L.; Möstl, C.; Eastwood, J. P. +4 more
Prediction of the effects of coronal mass ejections (CMEs) on Earth strongly depends on knowledge of the interplanetary magnetic field southward component, B z . Predicting the strength and duration of B z inside a CME with sufficient accuracy is currently impossible, forming the so-called B z problem. Here, w…
Measuring the Magnetic Field of Coronal Mass Ejections Near the Sun Using Pulsars
White, S. M.; Taylor, G. B.; Howard, T. A. +2 more
The utility of Faraday rotation to measure the magnetic field of the solar corona and large-scale transients within is a small, yet growing field in solar physics. This is largely because it has been recognized as a potentially valuable frontier in space weather studies, because the ability to measure the intrinsic magnetic field within coronal ma…
A Three-dimensional Model of Active Region 7986: Comparison of Simulations with Observations
Downs, Cooper; Linker, Jon A.; Mikić, Zoran +2 more
In the present study, we use a forward modeling method to construct a 3D thermal structure encompassing active region 7986 of 1996 August. The extreme ultraviolet (EUV) emissions are then computed and compared with observations. The heating mechanism is inspired by a theory on Alfvén wave turbulence dissipation. The magnetic structure is built fro…
Tether-cutting Reconnection between Two Solar Filaments Triggering Outflows and a Coronal Mass Ejection
Zhang, Jun; Li, Leping; Chen, Huadong +1 more
Triggering mechanisms of solar eruptions have long been a challenge. A few previous case studies have indicated that preceding gentle filament merging via magnetic reconnection may launch following intense eruption, according to the tether-cutting (TC) model. However, the detailed process of TC reconnection between filaments has not been exhibited…
Ion Dynamics at a Rippled Quasi-parallel Shock: 2D Hybrid Simulations
Wang, Shui; Hao, Yufei; Lu, Quanming +1 more
In this paper, two-dimensional hybrid simulations are performed to investigate ion dynamics at a rippled quasi-parallel shock. The results show that the ripples around the shock front are inherent structures of a quasi-parallel shock, and the re-formation of the shock is not synchronous along the surface of the shock front. By following the trajec…
The Distribution of Mass Surface Densities in a High-mass Protocluster
Kainulainen, Jouni; Tan, Jonathan C.; Lim, Wanggi +2 more
We study the probability distribution function (PDF) of mass surface densities, Σ, of infrared dark cloud (IRDC) G028.37+00.07 and its surrounding giant molecular cloud. This PDF constrains the physical processes, such as turbulence, magnetic fields, and self-gravity, that are expected to be controlling cloud structure and star formation activity.…
Observations of Oppositely Directed Umbral Wavefronts Rotating in Sunspots Obtained from the New Solar Telescope of BBSO
Chen, J.; Banerjee, D.; Su, J. T. +7 more
We study the umbral waves as observed by chromospheric imaging observations of two sunspots with the New Solar Telescope at the Big Bear Solar Observatory. We find that the wavefronts (WFs) rotate clockwise and form a one-armed spiral structure in the first sunspot, whereas two- and three-armed structures arise in the second sunspot where the WFs …
Searching for the 3.5 keV Line in the Stacked Suzaku Observations of Galaxy Clusters
Bulbul, Esra; Markevitch, Maxim; Smith, Randall K. +5 more
We perform a detailed study of the stacked Suzaku observations of 47 galaxy clusters, spanning a redshift range of 0.01-0.45, to search for the unidentified 3.5 keV line. This sample provides an independent test for the previously detected line. We detect a 2σ -significant spectral feature at 3.5 keV in the spectrum of the full sample. When the sa…
Broad [C II] Line Wings as Tracer of Molecular and Multi-phase Outflows in Infrared Bright Galaxies
Lutz, D.; Genzel, R.; Poglitsch, A. +13 more
We report a tentative correlation between the outflow characteristics derived from OH absorption at 119 µm and [C II] emission at 158 µm in a sample of 22 local and bright ultraluminous infrared galaxies (ULIRGs). For this sample, we investigate whether [C II] broad wings are a good tracer of molecular outflows, and how the two tracers…