Search Publications
Toward Waveform Heliotomography: Observing Interactions of Helioseismic Waves with a Sunspot
Zhao, Junwei; Kosovichev, Alexander G.; Ilonidis, Stathis
We investigate how helioseismic waves that originate from effective point sources interact with a sunspot. These waves are reconstructed from observed stochastic wavefields on the Sun by cross-correlating photospheric Doppler-velocity signals. We select the wave sources at different locations relative to the sunspot, and investigate the p- and f-m…
Evaluating predictions of ICME arrival at Earth and Mars
Odstrcil, D.; Vennerstrom, S.; Falkenberg, T. V. +5 more
We present a study of interplanetary coronal mass ejection (ICME) propagation to Earth and Mars. Because of the significant space weather hazard posed by ICMEs, understanding and predicting their arrival and impact at Mars is important for current and future robotic and manned missions to the planet. We compare running ENLILv2.6 with coronal mass …
Astrometry with the MCAO instrument MAD. An analysis of single-epoch data obtained in the layer-oriented mode
Kürster, M.; Rix, H. -W.; Arcidiacono, C. +2 more
Context. Current instrument developments at the largest telescopes worldwide involve the installation of multi-conjugated adaptive optics (MCAO) modules. The large field of view and more uniform correction provided by these systems is not only highly beneficial for photometric studies but also for astrometric analysis of, e.g., large dense cluster…
Far-ultraviolet Number Counts of Field Galaxies
Gardner, Jonathan P.; Teplitz, Harry I.; de Mello, Duilia F. +2 more
The far-ultraviolet (FUV) number counts of galaxies constrain the evolution of the star formation rate density of the universe. We report the FUV number counts computed from FUV imaging of several fields including the Hubble Ultra Deep Field, the Hubble Deep Field North, and small areas within the GOODS-North and South fields. These data were obta…
Evolution of Spinning and Braiding Helicity Fluxes in Solar Active Region NOAA 10930
Ravindra, B.; Yoshimura, Keiji; Dasso, Sergio
The line-of-sight magnetograms from Solar Optical Telescope Narrowband Filter Imager observations of NOAA Active Region 10930 have been used to study the evolution of spinning and braiding helicities over a period of five days starting from 2006 December 9. The north (N) polarity sunspot was the follower and the south (S) polarity sunspot was the …
AKARI-CAS—Online Service for AKARI All-Sky Catalogues
Oyabu, S.; Yamamura, I.; Ishihara, D. +10 more
The AKARI All-Sky Catalogues are an important infrared astronomical database for next-generation astronomy that take over the IRAS catalog. We have developed an online service, AKARI Catalogue Archive Server (AKARI-CAS), for astronomers. The service includes useful and attractive search tools and visual tools. One of the new features of AKARI-CAS …
New insights on the solar core
Eff-Darwich, A.; García, R. A.; Garrido, R. +11 more
Since the detection of the asymptotic properties of the dipole gravity modes in the Sun, the quest to find individual gravity modes has continued. An extensive and deeper analysis of 14 years of continuous GOLF/SoHO observational data, unveils the presence of a pattern of peaks that could be interpreted as individual dipole gravity modes in the fr…
Detection of currents and associated electric fields in Titan's ionosphere from Cassini data
Lewis, G. R.; Coates, A. J.; Dougherty, M. K. +13 more
We present observations from three Cassini flybys of Titan using data from the radio and plasma wave science, magnetometer and plasma spectrometer instruments. We combine magnetic field and cold plasma measurements with calculated conductivities and conclude that there are currents of the order of 10 to 100 nA m-2 flowing in the ionosph…
On accelerated magnetosheath flows under northward IMF
Farrugia, C. J.; Erkaev, N. V.; Harris, B. +1 more
We study the acceleration of magnetosheath plasma using a semi-analytical magnetic string approach for a range of solar wind Alfvén Mach numbers, MA, between 2 and 20. We work with an IMF vector perpendicular to the solar wind velocity, Vsw, and pointing north. We do not invoke magnetic reconnection. Our results indicate that…
Structure of the outer layers of cool standard stars
Blommaert, J. A. D. L.; Eriksson, K.; Dowell, C. D. +6 more
Context. Among late-type red giants, an interesting change occurs in the structure of the outer atmospheric layers as one moves to later spectral types in the Hertzsprung-Russell diagram: a chromosphere is always present, but the coronal emission diminishes and a cool massive wind steps in.
Aims: Where most studies have focussed on short-wave…