Search Publications
The Odd Offset between the Galactic Disk and Its Bar in NGC~3906
Ho, Luis C.; Erroz-Ferrer, Santiago; Schinnerer, Eva +27 more
We use mid-infrared 3.6 and 4.5 µm imaging of NGC 3906 from the Spitzer Survey of Stellar Structure in Galaxies (S4G) to understand the nature of an unusual offset between its stellar bar and the photometric center of an otherwise regular, circular outer stellar disk. We measure an offset of ∼910 pc between the center of the stell…
Families of Granules, Flows, and Acoustic Events in the Solar Atmosphere from Hinode Observations
Roudier, T.; Rieutord, M.; Malherbe, J. -M. +1 more
We investigate the relationship between trees of fragmenting granules (TFG), horizontal and vertical flows, and acoustic events (AE) in the photospheric network. AE are spatially concentrated and short-duration locations of acoustic energy flux. We performed observations at disk center of a 2D field of view (FOV) with high spatial and temporal res…
Pile driving models for the evaluation of soil penetration resistance measurements from planetary subsurface probes
Kömle, Norbert I.; Kargl, Günter; Poganski, Joshua +1 more
Several planetary lander missions conducted in the past and planned for the near future have instruments on board, which are dedicated to the determination of various material properties, among them mechanical properties of the surface like material strength and penetration resistance. In this paper two instruments are considered in more detail: (…
Comparative Morphology of Solar Relativistic Particle Events
Valtonen, Eino; Kocharov, Leon; Ryan, James M. +2 more
Time profiles of the 0.25-10 MeV electrons and the ∼(0.1-1) GeV nucleon-1 protons and helium associated with two solar coronal mass ejections (CMEs) are analyzed with a newly formulated method based on modeling of the particle transport in the interplanetary medium. With the modeling, we fit the observed angular distribution of solar pa…
New insights into the Late Amazonian zonal shrinkage of the martian south polar plateau
Fairén, Alberto G.; Kargel, Jeffrey S.; Baker, Victor R. +9 more
The martian south polar plateau, Planum Australe, comprises the largest known water-ice surface deposit on the planet. Here, we present evidence for an episode of extensive polar plateau retreat during the Late Amazonian, which affected regions flanking circum-polar terrains located between Cavi Angusti and Sisyphi Montes.
Spectroscopic Infrared Extinction Mapping as a Probe of Grain Growth in IRDCs
Tan, Jonathan C.; Lim, Wanggi; Carey, Sean J.
We present spectroscopic tests of MIR to FIR extinction laws in IRDC G028.36+00.07, a potential site of massive star and star cluster formation. Lim & Tan developed methods of FIR extinction mapping of this source using Spitzer-MIPS 24 µm and Herschel-PACS 70 µm images, and by comparing to MIR Spitzer-IRAC 3-8 µm extinction m…
The relative proportions of water group ions in Saturn's inner magnetosphere: A preliminary study
Wilson, R. J.; Crary, F.; Bagenal, F. +2 more
We present a technique to gather ion composition information in the form of relative abundances of the water group ion species in Saturn's inner magnetosphere, utilizing the Cassini Plasma Spectrometer's Straight-Through Time-of-Flight data from two orbits in 2011. We show that between 4.75 and 8 Saturn radii H2O+ ions domina…
Modeling the effects of ionospheric oxygen outflow on bursty magnetotail flows
Merkin, V. G.; Hughes, W. J.; Moore, T. E. +2 more
Using a global multifluid MHD model, we demonstrate the effects of magnetospheric O+ on bursty magnetotail flows. We carry out two simulations without ionospheric outflow to use as baseline, one driven by real solar wind data and one driven by idealized solar wind. Solar wind data from 1 October 2001 are used as a storm time solar wind …
INTEGRAL discovery of unusually long broad-band X-ray activity from the Supergiant Fast X-ray Transient IGR J18483-0311
Sidoli, L.; Bird, A. J.; Bazzano, A. +1 more
We report on a broad-band X-ray study (0.5-250 keV) of the Supergiant Fast X-ray Transient IGR J18483-0311 using archival INTEGRAL data and a new targeted XMM-Newton observation. Our INTEGRAL investigation discovered for the first time an unusually long X-ray activity (3-60 keV) which continuously lasted for at least ∼11 d, i.e. a significant frac…
Magnetic fields in Neutron Stars
Rea, N.; Pons, J. A.; Miralles, J. A. +1 more
Isolated neutron stars show a diversity in timing and spectral properties, which has historically led to a classification in different sub-classes. The magnetic field plays a key role in many aspects of the neutron star phenomenology: it regulates the braking torque responsible for their timing properties and, for magnetars, it provides the energy…