Search Publications
Plasma and Magnetic Field Characteristics of Solar Coronal Mass Ejections in Relation to Geomagnetic Storm Intensity and Variability
Wang, Rui; Yang, Zhongwei; Liu, Ying D. +5 more
The largest geomagnetic storms of solar cycle 24 so far occurred on 2015 March 17 and June 22 with {D}{st} minima of -223 and -195 nT, respectively. Both of the geomagnetic storms show a multi-step development. We examine the plasma and magnetic field characteristics of the driving coronal mass ejections (CMEs) in connection with the de…
Understanding star formation in molecular clouds. II. Signatures of gravitational collapse of IRDCs
Schneider, N.; Ossenkopf, V.; Csengeri, T. +6 more
We analyse column density and temperature maps derived from Herschel dust continuum observations of a sample of prominent, massive infrared dark clouds (IRDCs) i.e. G11.11-0.12, G18.82-0.28, G28.37+0.07, and G28.53-0.25. We disentangle the velocity structure of the clouds using 13CO 1→0 and 12CO 3→2 data, showing that these I…
HST Imaging of Fading AGN Candidates. I. Host-galaxy Properties and Origin of the Extended Gas
Schawinski, Kevin; Keel, William C.; Urry, C. Megan +11 more
We present narrow- and medium-band Hubble Space Telescope imaging, with additional supporting ground-based imaging, spectrophotometry, and Fabry-Perot interferometric data, for eight galaxies identified as hosting a fading active galactic nucleus (AGN). These are selected to have AGN-ionized gas projected \gt 10 kpc from the nucleus and energy bud…
The composition of a disrupted extrasolar planetesimal at SDSS J0845+2257 (Ton 345)
Gänsicke, B. T.; Pala, A. F.; Breedt, E. +4 more
We present a detailed study of the metal-polluted DB white dwarf SDSS J0845+2257 (Ton 345). Using high-resolution Hubble Space Telescope/Cosmic Origins Spectrograph and Very Large Telescope spectroscopy, we have detected hydrogen and 11 metals in the atmosphere of the white dwarf. The origin of these metals is almost certainly the circumstellar di…
The dust grain size-stellar luminosity trend in debris discs
Pawellek, Nicole; Krivov, Alexander V.
The cross-section of material in debris discs is thought to be dominated by the smallest grains that can still stay in bound orbits despite the repelling action of stellar radiation pressure. Thus the minimum (and typical) grain size smin is expected to be close to the radiation pressure blowout size sblow. Yet a recent analy…
Ultradeep IRAC Imaging Over the HUDF and GOODS-South: Survey Design and Imaging Data Release
Trenti, M.; Oesch, P. A.; Carollo, C. M. +11 more
The IRAC ultradeep field and IRAC Legacy over GOODS programs are two ultradeep imaging surveys at 3.6 and 4.5 µm with the Spitzer Infrared Array Camera (IRAC). The primary aim is to directly detect the infrared light of reionization epoch galaxies at z > 7 and to constrain their stellar populations. The observations cover the Hubble Ultra…
Correlated optical, X-ray, and γ-ray flaring activity seen with INTEGRAL during the 2015 outburst of V404 Cygni
Greiner, J.; Mas-Hesse, J. M.; Tomsick, J. A. +20 more
After 25 years of quiescence, the microquasar V404 Cyg entered a new period of activity in June 2015. This X-ray source is known to undergo extremely bright and variable outbursts seen at all wavelengths. It is therefore an object of prime interest to understand the accretion-ejection connections. These can, however, only be probed through simulta…
New Near-infrared Period-Luminosity-Metallicity Relations for RR Lyrae Stars and the Outlook for Gaia
Luri, X.; Clementini, G.; Ripepi, V. +6 more
We present results of the analysis of 70 RR Lyrae stars located in the bar of the Large Magellanic Cloud (LMC). Combining the spectroscopically determined metallicity of these stars from the literature with precise periods from the OGLE III catalog and multi-epoch Ks photometry from the VISTA survey of the Magellanic Clouds system, we d…
Emergent cosmology, inflation and dark energy
Herrera, Ramón; Guendelman, Eduardo; Labrana, Pedro +2 more
A new class of gravity-matter models defined in terms of two independent non-Riemannian volume forms (alternative generally covariant integration measure densities) on the space-time manifold are studied in some detail. These models involve an additional (square of the scalar curvature) term as well as scalar matter field potentials of appropriate…
The Azimuthal Dependence of Outflows and Accretion Detected Using O VI Absorption
Charlton, Jane C.; Kacprzak, Glenn G.; Churchill, Christopher W. +2 more
We report a bimodality in the azimuthal angle (Φ) distribution of gas around galaxies traced by O vi absorption. We present the mean Φ probability distribution function of 29 Hubble Space Telescope-imaged O vi absorbing (EW > 0.1 Å) and 24 non-absorbing (EW < 0.1 Å) isolated galaxies (0.08 \lt z \lt 0.67) within ∼200 kpc of background quasar…