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Larmor radius size density holes discovered in the solar wind upstream of Earth's bow shock
Dandouras, I.; Lucek, E.; Rème, H. +9 more
The Cluster and Double Star satellites recently observed plasma density holes upstream of Earth's collisionless bow shock to apogee distances of ∼19 and 13 earth radii, respectively. A survey of 147 isolated density holes using 4s time resolution data shows they have a mean duration of ∼17.9±10.4s, but holes as short as 4s are observed. The averag…
Multiwavelength Observations of EXO 0748-676. I. Reprocessing of X-Ray Bursts
Charles, P. A.; Horne, Keith; O'Brien, K. +5 more
We present high time-resolution multiwavelength observations of X-ray bursts in the low-mass X-ray binary UY Vol. Strong reprocessed signals are present in the ultraviolet and optical, lagged and smeared with respect to the X-rays. The addition of far-ultraviolet coverage for one burst allows much tighter constraints on the temperature and geometr…
Computational Acoustics in Spherical Geometry: Steps toward Validating Helioseismology
Christensen-Dalsgaard, J.; Schou, J.; Roth, M. +6 more
Throughout the past decade, detailed helioseismic analyses of observations of solar surface oscillations have led to advances in our knowledge of the structure and dynamics of the solar interior. Such analyses involve the decomposition of time series of the observed surface oscillation pattern into its constituent wave modes, followed by inversion…
Three-dimensional Simulation of Gamma-Ray Emission from Asymmetric Supernovae and Hypernovae
Maeda, Keiichi
Hard X- and γ-ray spectra and light curves resulting from radioactive decays are computed for aspherical (jetlike) and energetic supernova models (representing the prototypical hypernova SN 1998bw), using a three-dimensional energy- and time-dependent Monte Carlo scheme. The emission is characterized by (1) early emergence of high-energy emission,…
Gemini/GMOS spectra of globular clusters in the Virgo giant elliptical NGC 4649
Forbes, Duncan A.; Beasley, Michael A.; Zepf, Stephen E. +8 more
NGC 4649 (M60) is one of a handful of giant Virgo ellipticals. We have obtained Gemini/GMOS (Gemini North Multi-Object Spectrograph) spectra for 38 globular clusters (GCs) associated with this galaxy. Applying the multi-index χ2 minimization technique of Proctor and Sansom with the single stellar population models of Thomas, Maraston an…
Dwarf novae in the Hamburg quasar survey: rarer than expected
Gänsicke, B. T.; Hagen, H. -J.; Engels, D. +12 more
Aims.We report the discovery of five new dwarf novae that were spectroscopically identified in the Hamburg Quasar Survey (HQS), and discuss the properties of the sample of new dwarf novae from the HQS.
Methods.Follow-up time-resolved spectroscopy and photometry have been obtained to characterise the new systems.
Results.The orbital periods d…
XMM-Newton and Optical Follow-up Observations of SDSS J093249.57+472523.0 and SDSS J102347.67+003841.2
Anderson, Scott F.; Brinkmann, J.; Szkody, Paula +5 more
We report follow-up XMM-Newton and ground-based optical observations of the unusual X-ray binary SDSS J102347.67+003841.2 (=FIRST J102347.6+003841) and a new candidate intermediate polar (IP) found in the Sloan Digital Sky Survey: SDSS J093249.57+472523.0. SDSS J1023 was observed in its low state, with similar magnitude/color (V=17.4 and B=17.9) a…
The role of the LIRG and ULIRG phases in the evolution of Ks-selected galaxies
Le Floc'h, E.; Dole, H.; Lagache, G. +5 more
Aims.We investigate the role of the luminous infrared galaxy (LIRG) and ultra-luminous infrared galaxy (ULIRG) phases in the evolution of K_s-selected galaxies and, in particular, Extremely Red Galaxies (ERGs).
Methods: .With this aim, we compare the properties of a sample of 2905 K_s<21.5 (Vega mag) galaxies in the GOODS/CDFS with the sub-…
SS 433: a phenomenon imitating a Wolf-Rayet star
Ábrahám, P.; Fuchs, Y.; Koch Miramond, L.
We present mid-infrared (2-12 µm) spectra of the microquasar SS 433 obtained with the Infrared Space Observatory (spectroscopic mode of ISOPHOT and ISOCAM). We compare them to the spectra of four Wolf-Rayet stars: WR 78, WR 134, WR 136, and WR 147 in the same wavelength range. The mid-infrared spectrum of SS 433 mainly shows ion{H}{i} and io…
A Stellar-Mass Black Hole in the Ultraluminous X-Ray Source M82 X-1?
Okajima, Takashi; Ebisawa, Ken; Kawaguchi, Toshihiro
We have analyzed the archival XMM-Newton data of the bright ultraluminous X-ray source M82 X-1 with a 105 ks exposure when the source was in the steady state. Thanks to the high photon statistics from the large effective area and long exposure, we were able to discriminate different X-ray continuum spectral models. Neither the standard accretion d…