Search Publications
Circumnuclear Structures in Megamaser Host Galaxies
Greene, Jenny E.; Seth, Anil C.; Henkel, Christian +4 more
Using the Hubble Space Telescope, we identify circumnuclear (100-500 pc scale) structures in nine new H2O megamaser host galaxies to understand the flow of matter from kpc-scale galactic structures down to the supermassive black holes (SMBHs) at galactic centers. We double the sample analyzed in a similar way by Greene et al. and consid…
Interferometric evidence for quantum heated particles in the inner region of protoplanetary disks around Herbig stars
Waters, L. B. F. M.; Dominik, C.; Benisty, M. +6 more
Context. To understand the chemical composition of planets, it is important to know the chemical composition of the region where they form in protoplanetary disks. Because of its fundamental role in chemical and biological processes, carbon is a key element to trace.
Aims: We identify the carriers and processes behind the extended near-infrar…
A Large-scale Plume in an X-class Solar Flare
Fleishman, Gregory D.; Nita, Gelu M.; Gary, Dale E.
Ever-increasing multi-frequency imaging of solar observations suggests that solar flares often involve more than one magnetic fluxtube. Some of the fluxtubes are closed, while others can contain open fields. The relative proportion of nonthermal electrons among those distinct loops is highly important for understanding energy release, particle acc…
Dynamics of non-spherical dust in the coma of 67P/Churyumov- Gerasimenko constrained by GIADA and ROSINA data
Fulle, M.; Bieler, A.; Fougere, N. +6 more
Among the comet 67P/Churyumov-Gerasimenko (67P/C-G) in situ measurements, the closest that have ever been performed at a comet nucleus, are also those of speed, mass, and cross-section of cometary grains performed by the Grain Impact Analyser and Dust Accumulator (GIADA) instrument. To interpret GIADA data, we performed dust dynamical numerical si…
The Life Cycle of Active Region Magnetic Fields
Cheung, M. C. M.; van Driel-Gesztelyi, L.; Martínez Pillet, V. +1 more
We present a contemporary view of how solar active region magnetic fields are understood to be generated, transported and dispersed. Empirical trends of active region properties that guide model development are discussed. Physical principles considered important for active region evolution are introduced and advances in modeling are reviewed.
Analysis of R-band observations of an outburst of Comet 29P/Schwassmann-Wachmann 1 to place constraints on the nucleus' rotation state
Schambeau, Charles A.; Fernández, Yanga R.; Samarasinha, Nalin H. +2 more
We present analysis of five nights of R-band observations of Comet 29P/Schwassmann-Wachmann 1 (SW1) taken on September 2008 which show the comet undergoing an outburst. Coma morphology shows a projected asymmetric shell of material expanding radially and four linear features on the northern side of the coma at position angles 37°, 78°, 300°, and 3…
Effects of Solar Activity on the Local Interstellar Magnetic Field Observed by Voyager 1 and IBEX
McComas, D. J.; Schwadron, N. A.
Interstellar Boundary Explorer (IBEX) observations have shown enhanced energetic neutral atom emission from a narrow, circular ribbon likely centered on the direction of the magnetic field in the local interstellar medium (LISM). IBEX observations are compared to Voyager 1's direct observations of the magnetic field in the LISM, which reveals stru…
The transient topside layer and associated current sheet in the ionosphere of Mars
Gurnett, Donald A.; Halekas, Jasper S.; DiBraccio, Gina A. +2 more
Radar soundings from the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument on board the Mars Express spacecraft have shown that transient layers exist in the dayside upper ionosphere of Mars. The most prominent of these features is a second layer at an altitude near 200 km, well above that of the main photoionization l…
The 26 December 2001 Solar Eruptive Event Responsible for GLE63: III. CME, Shock Waves, and Energetic Particles
Klein, K. -L.; Grechnev, V. V.; Kochanov, A. A. +2 more
The SOL2001-12-26 moderate solar eruptive event (GOES importance M7.1, microwaves up to 4000 sfu at 9.4 GHz, coronal mass ejection (CME) speed 1446 km s−1) produced strong fluxes of solar energetic particles and ground-level enhancement (GLE) of cosmic-ray intensity (GLE63). To find a possible reason for the atypically high proton outco…
Ridge-like lava tube systems in southeast Tharsis, Mars
Huang, Jun; Xiao, Long; Zhao, Jiannan +2 more
Lava tubes are widely distributed in volcanic fields on a planetary surface and they are important means of lava transportation. We have identified 38 sinuous ridges with a lava-tube origin in southeast Tharsis. The lengths vary between 14 and 740 km, and most of them occur in areas with slopes < 0.3°. We analyzed their geomorphology in detail …