Search Publications
The temperature and width of an active fissure on Enceladus measured with Cassini VIMS during the 14 April 2012 South Pole flyover
Hedman, Matthew M.; Sotin, Christophe; Baines, Kevin H. +10 more
The width and temperature of the active fissures on Saturn’s satellite Enceladus provide key observable constraints on physical models of these geyser-like eruptions. We analyze a sequence of high spatial resolution near-infrared spectra acquired with VIMS at 0.025 s intervals during a 74 km altitude flyover of the South Pole of Enceladus by the C…
The ACS LCID Project. IX. Imprints of the Early Universe in the Radial Variation of the Star Formation History of Dwarf Galaxies
Skillman, Evan D.; Dolphin, Andrew; Monelli, Matteo +8 more
Based on Hubble Space Telescope observations from the Local Cosmology from Isolated Dwarfs project, we present the star formation histories, as a function of galactocentric radius, of four isolated Local Group dwarf galaxies: two dSph galaxies, Cetus and Tucana, and two transition galaxies (dTrs), LGS-3 and Phoenix. The oldest stellar populations …
On the self-regulation of intense star-formation in galaxies at z = 1-3
Boulanger, F.; Lehnert, M. D.; Di Matteo, P. +3 more
We have analyzed the properties of the Hα and [Nii]λ6583 rest-frame optical emission lines of a sample of 53 intensely star forming galaxies at z = 1.3 to 2.7 observed with SINFONI on the ESO-VLT. Similar to previous authors, we find large velocity dispersions in the lines, σ = few 10-250 km s-1. Our data agree well with simulations whe…
Long-term variation in the cloud-tracked zonal velocities at the cloud top of Venus deduced from Venus Express VMC images
Futaana, Yoshifumi; Imamura, Takeshi; Kouyama, Toru +2 more
We present observational evidence of the variation of the cloud-tracked zonal velocity by ~20 m s-1 with a timescale of a few hundred days in the southern low latitude region based on an analysis of cloud images taken by the Venus Monitoring Camera on board Venus Express. A spectral analysis suggests that the variation has a periodicity…
Properties of a Solar Flare Kernel Observed by Hinode and SDO
Young, P. R.; Doschek, G. A.; Warren, H. P. +1 more
Flare kernels are compact features located in the solar chromosphere that are the sites of rapid heating and plasma upflow during the rise phase of flares. An example is presented from a M1.1 class flare in active region AR 11158 observed on 2011 February 16 07:44 UT for which the location of the upflow region seen by EUV Imaging Spectrometer (EIS…
Optical constants of refractory oxides at high temperatures. Mid-infrared properties of corundum, spinel, and α-quartz, potential carriers of the 13 µm feature
Mutschke, H.; Zeidler, S.; Posch, Th.
Context. Many cosmic dust species, among them refractory oxides, form at temperatures higher than 300 K. Nevertheless, most astrophysical studies are based on the room-temperature optical constants of solids, such as corundum and spinel. A more realistic approach is needed for these materials, especially in the context of modeling late-type stars.…
Kinematics of massive star ejecta in the Milky Way as traced by 26Al
Wang, Wei; Gerhard, Ortwin; Diehl, Roland +5 more
Context. Massive stars form in groups and their winds and supernova explosions create superbubbles up to kpc in size. The fate of their ejecta is of vital importance for the dynamics of the interstellar medium, for chemical evolution models, and the chemical enrichment of galactic halos and the intergalactic medium. However, ejecta kinematics and …
Data-based modelling of the Earth's dynamic magnetosphere: a review
Tsyganenko, N. A.
This paper reviews the main advances in the area of data-based modelling of the Earth's distant magnetic field achieved during the last two decades. The essence and the principal goal of the approach is to extract maximum information from available data, using physically realistic and flexible mathematical structures, parameterized by the most rel…
The shape of broad-line profiles in active galactic nuclei
Kollatschny, W.; Zetzl, M.
Aims: We present a study of the broad optical/UV emission line profiles in active galactic nuclei (AGN) to get information on the dominant velocity components (turbulence, rotation, etc.) in the central broad-line region (BLR).
Methods: We introduce line broadening simulations of emission line profiles and compare these results with the …
An Exponential Decline at the Bright End of the z = 6 Galaxy Luminosity Function
Willott, Chris J.; Kneib, Jean-Paul; Ilbert, Olivier +7 more
We present the results of a search for the most luminous star-forming galaxies at redshifts z ≈ 6 based on Canada-France-Hawaii Telescope Legacy Survey data. We identify a sample of 40 Lyman break galaxies (LBGs) brighter than magnitude z' = 25.3 across an area of almost 4 deg2. Sensitive spectroscopic observations of seven galaxies pro…