Search Publications
Population gradients and photometric metallicities in early- and transition-type dwarf galaxies: Clues from the Sculptor group
Rejkuba, M.; Da Costa, G. S.; Grebel, E. K. +3 more
Aims: We focus on the resolved stellar populations of one early-type and four transition-type dwarf galaxies in the Sculptor group, with the aim to examine the potential presence of population gradients and place constraints on their mean metallicities.
Methods: We use deep Hubble Space Telescope images to construct color-magnitude diagr…
Herschel/HIFI Search for H_2^{17}O and H_2^{18}O in IRC+10216: Constraints on Models for the Origin of Water Vapor
Cernicharo, José; Agúndez, Marcelino; Szczerba, Ryszard +7 more
We report the results of a sensitive search for the minor isotopologues of water, H_2^{17}O and H_2^{18}O, toward the carbon-rich asymptotic giant branch star IRC+10216 (a.k.a. CW Leonis) using the HIFI instrument on the Herschel Space Observatory. This search was motivated by the fact that any detection of isotopic enhancement in the H_2^{17}O an…
Pseudo altitude: A new perspective on the auroral density cavity
Karlsson, T.; Masson, A.; Marklund, G. T. +1 more
Studying the density distribution inside the auroral density cavity is complicated by the difficulties in achieving simultaneous measurements within the same flux tube at different altitudes. Comparisons between different events are complicated by variations in both the location of the density cavity and the location of the related potential struc…
Evidence for partial Taylor relaxation from changes in magnetic geometry and energy during a solar flare
Bloomfield, D. S.; Gallagher, P. T.; Murray, S. A.
Context. Solar flares are powered by energy stored in the coronal magnetic field, a portion of which is released when the field reconfigures into a lower energy state. Investigation of sunspot magnetic field topology during flare activity is useful to improve our understanding of flaring processes.
Aims: Here we investigate the deviation of t…
The influence of recent major crater impacts on the surrounding surfaces of (21) Lutetia
Jorda, L.; Kührt, E.; Thomas, N. +4 more
We present 3-D simulations of impacts into Asteroid 21 Lutetia, the subject of a fly-by by the European Space Agency’s Rosetta mission to Comet 67P/Churyumov-Gerasimenko. Using a 3-D shape model of the asteroid, impacts of sizes sufficient to reproduce the observed craters in Lutetia’s North Polar Crater Cluster (NPCC) as observed by the OSIRIS ex…
Limb imaging of the Venus O2 visible nightglow with the Venus Monitoring Camera
Hueso, R.; Witasse, O.; Opitz, A. +4 more
investigated the Venus O2 visible nightglow with imagery from the Venus Monitoring Camera on Venus Express. Drawing from data collected between April 2007 and January 2011, we study the global distribution of this emission, discovered in the late 1970s by the Venera 9 and 10 missions. The inferred limb-viewing intensities are on the ord…
Determination of wave vectors using the phase differencing method
Walker, S. N.; Moiseenko, I.
Due to the collisionless nature of space plasmas, plasma waves play an important role in the redistribution of energy between the various particle populations in many regions of geospace. In order to fully comprehend such mechanisms it is necessary to characterise the nature of the waves present. This involves the determination of properties such …
Red bulgeless galaxies in SDSS DR7. Are there any AGN hosts?
Ribeiro, B.; Coelho, B.; Antón, S. +1 more
With the main goal of finding bulgeless galaxies harbouring supermassive black holes and showing, at most, just residual star formation activity, we have selected a sample of massive bulgeless red sequence galaxies from the Sloan Digital Sky Survey - Data Release 7 (SDSS DR7), based on the New York University Value-Added Galaxy Catalogue. Multiwav…
The Broad Line Region in NGC 4051: An Inflow Illuminated by a 105 K Accretion Disk
Devereux, Nick; Heaton, Emily
Adopting a spherically symmetric steady-state ballistic inflow as the kinematic model for the gas distribution responsible for producing the Hα emission line, and a central black hole (BH) mass of 1.7 × 106 M ⊙ determined from prior reverberation mapping, leads to the following dimensions for the size of the broad line region…
The Mysterious Sickle Object in the Carina Nebula: A Stellar Wind Induced Bow Shock Grazing a Clump?
Burkert, Andreas; Preibisch, Thomas; Ratzka, Thorsten +1 more
Optical and near-infrared images of the Carina Nebula show a peculiar arc-shaped feature, which we call the "Sickle," next to the B-type star Trumpler 14 MJ 218. We use multi-wavelength observations to explore and constrain the nature and origin of the nebulosity. Using submillimeter data from APEX/LABOCA as well as Herschel far-infrared maps, we …