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The mass distribution of the unusual merging cluster Abell 2146 from strong lensing

Baum, Stefi A.; O'Dea, Christopher P.; McNamara, Brian R. +11 more

Abell 2146 consists of two galaxy clusters that have recently collided close to the plane of the sky, and it is unique in showing two large shocks on Chandra X-ray Observatory images. With an early stage merger, shortly after first core passage, one would expect the cluster galaxies and the dark matter to be leading the X-ray emitting plasma. In t…

XMM-Newton observations of the peculiar cataclysmic variable Lanning 386: X-ray evidence for a magnetic primary

Garnavich, P. M.; Kennedy, M. R.; Fausnaugh, M. +2 more

We present the first X-ray observations of the eclipsing cataclysmic variables Lanning 386 and MASTER OTJ192328.22+612413.5, possible SW Sextantis systems. The X-ray light curve of Lanning 386 shows deep eclipses, similar to the eclipses seen in the optical light curve, confirming the high inclination of the system. There is evidence of a periodic…

Magnetic reconnection during steady magnetospheric convection and other magnetospheric modes

Cowley, Stanley W. H.; Gérard, Jean-Claude; Hubert, Benoit +1 more

We use remote sensing of the proton aurora with the IMAGE-FUV SI12 (Imager for Magnetopause to Aurora Global Exploration-Far Ultraviolet-Spectrographic Imaging at 121.8 nm) instrument and radar measurements of the ionospheric convection from the SuperDARN (Super Dual Aurora Radar Network) facility to estimate the open magnetic flux in the Earth's …

The Role of the Upper Atmosphere for Dawn-Dusk Differences in the Coupled Magnetosphere-Ionosphere-Thermosphere System

Haaland, S. E.; Förster, M.; Doornbos, E.

Three-dimensional Monte Carlo dust radiative transfer study of the H-poor planetary nebula IRAS 18333-2357 located in M22

Muthumariappan, C.

We analyse the characteristics of dust and its distribution in the planetary nebula IRAS 18333-2357 located in M22 using a three-dimensional radiative transfer code Hochunk3D. The spectral energy distribution was constructed using ultraviolet, optical and infrared archival data. We also have used Spitzer 8-µm and Wide-field Infrared Survey E…

Candidate exoplanet host HD 131399A: a nascent Am star

Przybilla, N.; Buder, S.; Aschenbrenner, P.

Direct imaging suggests that there is a Jovian exoplanet around the primary A-star in the triple-star system HD 131399. We investigate a high-quality spectrum of the primary component HD 131399A obtained with FEROS on the ESO/MPG 2.2 m telescope, aiming to characterise the star's atmospheric and fundamental parameters, and to determine elemental a…

Modelling the effect of absorption from the interstellar medium on transient black hole X-ray binaries

Vaughan, S.; Wynn, G. A.; Eckersall, A. J.

All observations of Galactic X-ray binaries are affected by absorption from gas and dust in the interstellar medium (ISM) which imprints narrow (line) and broad (photoelectric edges) features on the continuum emission spectrum of the binary. Any spectral model used to fit data from a Galactic X-ray binary must therefore take account of these featu…

Hot DA white dwarf model atmosphere calculations: including improved Ni PI cross-sections

Barstow, M. A.; Holberg, J. B.; Hubeny, I. +2 more

To calculate realistic models of objects with Ni in their atmospheres, accurate atomic data for the relevant ionization stages need to be included in model atmosphere calculations. In the context of white dwarf stars, we investigate the effect of changing the Ni IV-VI bound-bound and bound-free atomic data on model atmosphere calculations. Models …

Multiwavelength monitoring of a very active dwarf nova AX J1549.8-5416 with an unusually high duty cycle

Gelfand, Joseph D.; Bernardini, Federico; Lewis, Fraser +5 more

We present the results of our analysis of new optical, ultraviolet (UV) and X-ray observations of a highly variable source - AX J1549.8-5416. Both the detection of several fast rise, exponential decay outbursts in the optical light curve and the lack of He II emission lines in the optical spectra suggest AX J1549.8-5416 is a cataclysmic variable o…

LISA Pathfinder first results

Vetrugno, D.

LISA Pathfinder (LPF) is an in-flight technological demonstrator designed and launched to prove the feasibility of sub-femto-g free fall of kilo-sized test masses (TM), an essential ingredient for the future gravitational wave observatory from space. Half a year after launch, the first results are available and show an incredibly well-performing i…