Search Publications
Spectral Properties of Large Gradual Solar Energetic Particle Events. I. Fe, O, and Seed Material
Cohen, C. M. S.; Mewaldt, R. A.; Schwadron, N. A. +7 more
We have surveyed ∼0.1-100 MeV nucleon-1 O and Fe fluence spectra during 46 isolated, large gradual SEP events observed at ACE during solar cycles 23 and 24. Most SEP spectra are well represented by the four-parameter Band function with a normalization constant, low-energy spectral slope, high-energy spectral slope, and break energy. The…
NGC 6362: The Least Massive Globular Cluster with Chemically Distinct Multiple Populations
Dalessandro, Emanuele; Salaris, Maurizio; Mucciarelli, Alessio +6 more
We present the first measure of Fe and Na abundances in NGC 6362, a low-mass globular cluster (GC) where first- and second-generation stars are fully spatially mixed. A total of 160 member stars (along the red giant branch (RGB) and the red horizontal branch (RHB)) were observed with the multi-object spectrograph FLAMES at the Very Large Telescope…
How Lyman Alpha Emission Depends on Galaxy Stellar Mass
Finkelstein, Steven L.; Blanc, Guillermo A.; Oyarzún, Grecco A. +6 more
In this work, we show how the stellar mass (M *) of galaxies affects the 3 < z < 4.6 Lyα equivalent width (EW) distribution. To this end, we design a sample of 629 galaxies in the M * range 7.6\lt {log}{M}*/{M}⊙ \lt 10.6 from the 3D-HST/CANDELS survey. We perform spectroscopic observations of this …
The Case for PSR J1614-2230 as a NICER Target
Miller, M. Coleman
The Neutron star Interior Composition ExploreR (NICER) is expected to launch in 2017 and will gather X-ray data on neutron stars and other high-energy sources from a berth on the International Space Station. Its prime scientific goal is to measure the masses and radii of non-accreting neutron stars via fits to the energy-dependent waveforms produc…
NUSTAR Unveils a Heavily Obscured Low-luminosity Active Galactic Nucleus in the Luminous Infrared Galaxy NGC 6286
Sanders, D. B.; Stern, D.; Treister, E. +8 more
We report the detection of a heavily obscured active galactic nucleus (AGN) in the luminous infrared galaxy (LIRG) NGC 6286 identified in a 17.5 ks Nuclear Spectroscopic Telescope Array observation. The source is in an early merging stage and was targeted as part of our ongoing NuSTAR campaign observing local luminous and ultra-luminous infrared g…
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…