Search Publications
Spatial Distributions of Dust and Polycyclic Aromatic Hydrocarbons in the Nearby Elliptical Galaxy NGC 4589 Observed with AKARI
Onaka, Takashi; Sakon, Itsuki; Kaneda, Hidehiro +2 more
We report on near- to far-infrared (IR) observations of the nearby elliptical galaxy NGC 4589 by AKARI. NGC 4589 has acomplex stellar rotation field with aposition angle difference of 45° between the kinematic and morphological axes, although its morphology shows asmooth optical profile that closely follows the de Vaucouleurs law. The galaxy has a…
Three X-ray transients in M ;31 observed with Swift
Stiele, H.; Pietsch, W.; Haberl, F. +5 more
Aims: The purpose of this study is to find transient X-ray sources in M 31 and to investigate and classify their nature.
Methods: Three X-ray transients were observed with Swift. For each of the three X-ray transients, we used the Swift X-ray and optical data with observations from XMM-Newton and Chandra to investigate the lightcurves and the …
Discovery of a [WO] central star in the planetary nebula Th 2-A
Gamen, R.; Díaz, R. J.; Weidmann, W. A. +1 more
Context: About 2500 planetary nebulae are known in our Galaxy but only 224 have central stars with reported spectral types in the Strasbourg-ESO Catalogue of Galactic Planetary Nebulae (Acker et al. 1992; Acker et al. 1996).
Aims: We have started an observational program aiming to increase the number of PN central stars with spectral classific…
Measuring Stellar Radial Velocities with a Dispersed Fixed-Delay Interferometer
Ge, Jian; Mahadevan, Suvrath; Fleming, Scott W. +5 more
We demonstrate the ability to measure precise stellar barycentric radial velocities with the dispersed fixed-delay interferometer technique using the Exoplanet Tracker (ET), an instrument primarily designed for precision differential Doppler velocity measurements using this technique. Our barycentric radial velocities, derived from observations ta…
XTE J1901+014—the first low-mass Fast X-ray transient?
Lutovinov, A. A.; Karasev, D. I.; Burenin, R. A.
We continue to study the fast X-ray transient XTE J1901+014 discovered in 2002 by the RXTE observatory, whose nature has not yet been established. Based on the XMM-Newton observations of the source in 2006, we have obtained its energy spectrum, light curves, and power spectrum in the energy range 0.5 10 keV, which are in good agreement with our re…
The dynamics of the solar radiative zone
Turck-Chièze, Sylvaine; Talon, Suzanne
The picture of the solar radiative zone is evolving quickly. This review is separated in two parts. We first recall how the two powerful probes of the solar interior, namely the neutrinos and helioseismology have scrutinized the microscopic properties of the solar radiative plasma. Recent observations stimulate today complementary activities beyon…
The Funnel Geometry of Open Flux Tubes in the Low Solar Corona Constrained by O VI and Ne VIII Outflow
Lie-Svendsen, Øystein; Esser, Ruth; Byhring, Hanne S.
We carry out model calculations to show that observed outflow velocities of order 7-10 km s-1 of C IV and O VI ions, and 15-20 km s-1 of Ne VIII ions, are not only consistent with models of the solar wind from coronal holes but also place unique constraints on the degree of flow tube expansion as well as the location of the e…
Analysis of the FUSE Spectrum of the Hot, Evolved Star GD 605
Chayer, P.; Fontaine, G.; Wesemael, F. +2 more
We present an analysis of the atmospheric properties of the evolved, hydrogen-rich object GD 605 using FUSE, IUE, and optical spectra in conjunction with non-LTE (NLTE) model atmospheres and synthetic spectra. We also present an analysis of the interstellar medium along the line of sight toward this star. Our effective temperature determination re…
Unusual stripes in emission and absorption in solar radio bursts: Ropes of fibers in the meter wave band
Chernov, G. P.
Based on data from the spectrographs of IZMIRAN and Tremsdorf station (Astronomical Institute, Potsdam), we analyze the ropes of narrow-band fibers in the spectra of solar radio bursts in the meter wave band by invoking events of satellite data (SOHO/LASCO, EIT, MDI) for the analysis. We consider in detail basic properties of the ropes in four eve…
Cosmic Ray Transport and Production in the Galaxy: A Stochastic Propagation Simulation Approach
Zhang, Ming; Connell, J. J.; Rassoul, Hamid +1 more
Galactic cosmic-ray composition reflects the effects of nuclear interactions during propagation through the interstellar medium. In order to use measurements to determine the source of cosmic rays, one needs a model to deconvolute the propagation effect. This paper presents a new numerical method to solve cosmic-ray diffusive transport equations w…