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Constraints on the history of open-basin lakes on Mars from the composition and timing of volcanic resurfacing
Mustard, John F.; Goudge, Timothy A.; Head, James W. +1 more
Abundant evidence exists for valley network-related fluvial activity near the Noachian-Hesperian transition on Mars, and areally significant quantities of volcanic ridged plains were emplaced during this period as well. Thus, it is worthwhile to explore the hypothesis that lava-water interaction occurred on the surface of Mars at this time. We ana…
BR1202-0725: an extreme multiple merger at z = 4.7
Omont, A.; Gavazzi, R.; Salomé, P. +5 more
The radio-quiet quasar BR1202-0725 (z = 4.695) is a remarkable source with a bright northwest (NW) companion detected at submillimeter and radio wavelengths but invisible in the optical. In the absence of amplification by gravitational lensing, BR1202-0725 would be the most luminous binary CO and far-infrared (far-IR) source in the Universe. In th…
SN 2010ay is a Luminous and Broad-lined Type Ic Supernova within a Low-metallicity Host Galaxy
Price, P. A.; Berger, E.; Cline, T. +38 more
We report on our serendipitous pre-discovery detection and follow-up observations of the broad-lined Type Ic supernova (SN Ic) 2010ay at z = 0.067 imaged by the Pan-STARRS1 3π survey just ~4 days after explosion. The supernova (SN) had a peak luminosity, MR ≈ -20.2 mag, significantly more luminous than known GRB-SNe and one of the most …
Numerical Simulations of the Magnetic Rayleigh-Taylor Instability in the Kippenhahn-Schlüter Prominence Model. II. Reconnection-triggered Downflows
Shibata, Kazunari; Isobe, Hiroaki; Hillier, Andrew +1 more
The launch of the Hinode satellite has allowed high-resolution observations of supersonic bright downflows in quiescent prominences, known as prominence knots. We present observations in the Ca II H spectral line using the Solar Optical Telescope on board the Hinode satellite of a descending plasma knot of size ~900 km. The knot initially undergoe…
A clear view of the multifaceted dayside ionosphere of Mars
Tellmann, Silvia; Pätzold, Martin; Häusler, Bernd +10 more
By examining electron density profiles from the Mars Express Radio Science Experiment MaRS, we show that the vertical structure of the dayside ionosphere of Mars is more variable and more complex than previously thought. The top of the ionosphere can be below 250 km (25% occurrence rate) or above 650 km (1%); the topside ionosphere can be well-des…
Correlated X-ray/ultraviolet/optical variability in the very low mass AGN NGC 4395
McHardy, I.; Breedt, E.; Uttley, P. +4 more
We report the results of a 1-yr Swift X-ray/ultraviolet (UV)/optical programme monitoring the dwarf Seyfert nucleus in NGC 4395 in 2008-2009. The UV/optical flux from the nucleus was found to vary dramatically over the monitoring period, with a similar pattern of variation in each of the observed UV/optical bands (spanning 1900-5500 Å). In particu…
Of "Cocktail Parties" and Exoplanets
Waldmann, I. P.
The characterization of ever smaller and fainter extrasolar planets requires an intricate understanding of one's data and the analysis techniques used. Correcting the raw data at the 10-4 level of accuracy in flux is one of the central challenges. This can be difficult for instruments that do not feature a calibration plan for such high…
The Hubble Space Telescope Cluster Supernova Survey. III. Correlated Properties of Type Ia Supernovae and Their Hosts at 0.9 < Z < 1.46
Gladders, M. D.; Lidman, C.; Rubin, D. +36 more
Using the sample of Type Ia supernovae (SNe Ia) discovered by the Hubble Space Telescope (HST) Cluster Supernova Survey and augmented with HST-observed SNe Ia in the Great Observatories Origins Deep Survey (GOODS) fields, we search for correlations between the properties of SNe and their host galaxies at high redshift. We use galaxy color and quan…
Enceladus: A hypothesis for bringing both heat and chemicals to the surface
Matson, Dennis L.; Johnson, Torrence V.; Castillo-Rogez, Julie C. +1 more
The eruptive plumes and large heat flow (∼15 GW) observed by Cassini in the South Polar Region of Enceladus may be expressions of hydrothermal activity inside Enceladus. We hypothesize that a subsurface ocean is the heat reservoir for thermal anomalies on the surface and the source of heat and chemicals necessary for the plumes. The ocean is belie…
Empirical energy spectra of neutralized solar wind protons from the lunar regolith
Barabash, S.; Holmström, M.; Futaana, Y. +7 more
We present an empirical model of the energy spectra for hydrogen energetic neutral atoms (ENA) backscattered from the lunar surface based on Chandrayaan-1 Energetic Neutral Atom (CENA) observations. The observed energy spectra of the backscattered ENAs are well reproduced by Maxwell-Boltzmann distribution functions. The backscatter fraction is con…