Search Publications
XMM-Newton observation of the deep minimum state of PG 2112+059. A spectrum dominated by reflection from the accretion disk?
Clavel, J.; Guainazzi, M.; Schartel, N. +5 more
Context: Highly ionised absorbers and the frequent occurrence of relativistically broad iron fluorescence lines characterize the 0.2-10 keV spectra of (soft) X-ray weak quasars.
Aims: We constrain the physical conditions of the absorber and the broad iron line of the X-ray weak quasar
Structure of Titan's mid-range magnetic tail: Cassini magnetometer observations during the T9 flyby
Coates, A. J.; Dougherty, M. K.; Kurth, W. S. +5 more
We analyze the magnetic structure of Titan's mid-range magnetic tail (5-6 Titan radii downstream from the moon) during Cassini's T9 flyby. Cassini magnetometer (MAG) measurements reveal a well-defined, induced magnetic tail consisting of two lobes and a distinct central current sheet. MAG observations also indicate that Saturn's background magneti…
Is There Enhanced Depletion of Gas-Phase Nitrogen in Moderately Reddened Lines of Sight?
Snow, Theodore P.; Rachford, Brian L.; Jensen, Adam G.
We report on the abundance of interstellar neutral nitrogen (N I) for 30 sight lines, using data from the Far Ultraviolet Spectroscopic Explorer (FUSE) and the Hubble Space Telescope (HST). N I column densities are derived by measuring the equivalent widths of several ultraviolet absorption lines and subsequently fitting those to a curve of growth…
Field distributions and shapes of Langmuir wave packets observed by Ulysses in an interplanetary type III burst source region
Nulsen, A. L.; Cairns, Iver H.; Robinson, P. A.
There is no consensus on the mechanisms producing the intense bursty Langmuir wave packets routinely observed in source regions of interplanetary type III radio bursts. Using data from the Ulysses Fast Envelope Sampler (FES) near 4 AU, new analyses of the distributions of wavefields clearly separate the Langmuir waves into "intense localized struc…
Nondetection of Gravitationally Redshifted Absorption Lines in the X-Ray Burst Spectra of GS 1826-24
Kong, Albert K. H.; Miller, Jon M.; Kuulkers, Erik +6 more
During a 200 ks observation with the XMM-Newton Reflection Grating Spectrometer, we detected 16 type I X-ray bursts from GS 1826-24. We combined the burst spectra in an attempt to measure the gravitational redshifts from the surface of the neutron star. We divided the composite GS 1826-24 burst spectrum into three groups based on the blackbody tem…
The Metallicity of Intergalactic Gas in Cosmic Voids
Shull, J. Michael; Danforth, Charles W.; Stocke, John T. +2 more
We have used the Hubble STIS and FUSE archives of ultraviolet spectra of bright AGNs to identify intergalactic Lyα absorbers in nearby (z<=0.1) voids. From a parent sample of 651 Lyα absorbers, we identified 61 ``void absorbers'' located >1.4 h-170 Mpc from the nearest L* or brighter galaxy. Searching for met…
Photospheric flows around a quiescent filament
Bommier, V.; Schmieder, B.; Rondi, S. +7 more
Context: The horizontal photospheric flows below and around a filament are one of the components in the formation and evolution of filaments. Few studies exist because they require multiwalength time sequences at high spatial resolution.
Aims: Our objective is to measure the horizontal photospheric flows associated with the evolution and erupt…
Hubble Ultra Deep Field-JD2: Mid-Infrared Evidence for a z ~ 2 Luminous Infrared Galaxy
Papovich, Casey; Dickinson, Mark E.; Teplitz, Harry I. +5 more
The Hubble Ultra Deep Field source JD2 presented in Mobasher et al. is an unusual galaxy that is very faint at all wavelengths shortward of 1.1 µm. Photometric redshift fits to data between 0.4 and 8 µm yield a significant probability that it is an extremely massive galaxy at z~6.5. In this paper we present new photometry at 16 and 22 …
Interaction of magnetic field systems leading to an X1.7 flare due to large-scale flux tube emergence
Bommier, V.; Schmieder, B.; Li, H. +1 more
Aims:The aim of this paper is to understand the magnetic configuration and evolution of an active region, which permitted an X1.7 flare to be observed during the decaying phase of a long-duration X1.5 flare on 2005 September 13.
Methods: We performed a multi-wavelength analysis using data from space-borne (Solar and Heliospheric Observatory (S…
IGR J08408-4503: A New Recurrent Supergiant Fast X-Ray Transient
Götz, D.; von Kienlin, A.; De Luca, A. +3 more
The supergiant fast X-ray transient IGR J08408-4503 was discovered by INTEGRAL on 2006 May 15 during a bright flare. The source shows sporadic recurrent short bright flares, reaching a peak luminosity of 1036 ergs s-1 within less than 1 hr. The companion star is HD 74194, an Ob5Ib(f) supergiant star located at 3 kpc in the Ve…