Search Publications
Deflections of Fast Coronal Mass Ejections and the Properties of Associated Solar Energetic Particle Events
Gopalswamy, N.; Kahler, S. W.; Akiyama, S.
The onset times and peak intensities of solar energetic particle (SEP) events at Earth have long been thought to be influenced by the open magnetic fields of coronal holes (CHs). The original idea was that a CH lying between the solar SEP source region and the magnetic footpoint of the 1 AU observer would result in a delay in onset and/or a decrea…
Observation of High-speed Outflows in Coronal Loops Associated with Photospheric Magnetic Field Evolution
Liu, Y.; Su, J. T.; Liu, S. +2 more
Using SDO/AIA instruments, we provide an EUV observation of two adjacent loop strands (Loops 1 and 2) with one side of their footpoints rooted in the boundaries of active region (AR) NOAA 11158 and the other side in the quiet-Sun regions. The AR footpoints of Loop 1 were located in monopolar magnetic areas and those of Loop 2 in mixed polar areas …
Titan airglow during eclipse
Strobel, D. F.; West, R. A.; Gladstone, G. R. +4 more
Solar XUV photons can provide enough energy to account for the observed nitrogen UV dayglow emissions above 800 km, but a small or sporadic contribution from energetic particles cannot be ruled out. Furthermore, ion production at altitudes deeper than 800 km as inferred from radio occultation cannot be produced by solar XUV stimulation and implies…
Blending of Cepheids in M33
Macri, Lucas M.; Pellerin, Anne; Chavez, Joy M.
A precise and accurate determination of the Hubble constant based on Cepheid variables requires proper characterization of many sources of systematic error. One of these is stellar blending, which biases the measured fluxes of Cepheids and the resulting distance estimates. We study the blending of 149 Cepheid variables in M33 by matching archival …
External triggering of plasmoid development at Saturn
Winglee, R. M.; Paty, C. S.; Harnett, E. M. +1 more
The Cassini spacecraft has encountered multiple plasmoids in Saturn's magnetotail thought to be produced by tail reconnection. However, single spacecraft measurements make it difficult to determine plasmoid size, where they form, the composition, and the geometry of the plasma sheet when plasmoids are produced. This paper examines these issues usi…
A close look at the Centaurus A group of galaxies. IV. Recent star formation histories of late-type dwarfs around CenA
Crnojević, D.; Grebel, E. K.; Cole, A. A.
Aims: We study a sample of five dwarf irregular galaxies in the CenA/M 83 group, which are companions to the giant elliptical CenA. We aim at deriving their physical properties over their lifetime and compare them to those of dwarfs located in different environments.
Methods: We use archival HST/ACS data and apply synthetic color-magnitu…
Analytical shear and flexion of Einasto dark matter haloes
Baes, M.; Frutos-Alfaro, F.; Retana-Montenegro, E.
N-body simulations predict that dark matter haloes are described by specific density profiles on both galactic- and cluster-sized scales. Weak gravitational lensing through the measurements of their first and second order properties, shear and flexion, is a powerful observational tool for investigating the true shape of these profiles. One of the …
Regolith grain sizes of Saturn’s rings inferred from Cassini-CIRS far-infrared spectra
Spilker, Linda; Morishima, Ryuji; Edgington, Scott G.
We analyze far-infrared (10-650 cm-1) emissivity spectra of Saturn’s main rings obtained by the Cassini Composite Infrared Spectrometer (CIRS). In modeling of the spectra, the single scattering albedos of regolith grains are calculated using the Mie theory, diffraction is removed with the delta-Eddington approximation, and the hemispher…
A planetary companion around the K giant ɛ Corona Borealis
Lee, B. -C.; Park, M. -G.; Han, I. +2 more
Aims: Our aim is to search for and study the origin of the low-amplitude and long-periodic radial velocity (RV) variations in K giants.
Methods: We present high-resolution RV measurements of K2 giant ɛ CrB from February 2005 to January 2012 using the fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) at the Bohyunsan Optical Ast…
The Merger History, Active Galactic Nucleus, and Dwarf Galaxies of Hickson Compact Group 59
Hornschemeier, A. E.; Brandt, W. N.; Konstantopoulos, I. S. +16 more
Compact group galaxies often appear unaffected by their unusually dense environment. Closer examination can, however, reveal the subtle, cumulative effects of multiple galaxy interactions. Hickson Compact Group (HCG) 59 is an excellent example of this situation. We present a photometric study of this group in the optical (Hubble Space Telescope), …