Search Publications
Revealing the Nature of Algol Disks through Optical and UV Spectroscopy, Synthetic Spectra, and Tomography of TT Hydrae
Peters, Geraldine J.; Miller, Brendan; Budaj, Ján +2 more
We have developed a systematic procedure to study the disks in Algol-type binaries using spectroscopic analysis, synthetic spectra, and tomography. We analyzed 119 Hα spectra of TT Hya, an Algol-type eclipsing interacting binary, collected from 1985 to 2001. The new radial velocities enabled us to derive reliable orbital elements, including a smal…
The Mid-Infrared Emission of Seyfert Galaxies: A New Analysis of ISOCAM Data
Pérez García, A. M.; Acosta-Pulido, J. A.; Ramos Almeida, C. +1 more
We present mid-infrared data of a sample of 57 AGNs obtained with the instrument ISOCAM on board the Infrared Space Observatory (ISO) satellite. The images were obtained through the LW2 (6.75 µm) and LW7 (9.62 µm) filters. This is a new analysis of the Clavel et al. galaxy sample, which is divided into 26 type 1 (<=1.5) and 28 type …
Solar abundances of oxygen and neon derived from solar wind observations
Bochsler, P.
Context: Recently, a revision of the solar abundances of C, N, and O to substantially lower values has led to a controversy on solar opacities in the solar standard model and to the suggestion to revise the solar abundance of neon upward by as much as a factor of 1.6 leading to enhanced solar neon/oxygen abundance ratios by a factor of 3. Neon and…
Speed of Meridional Flows and Magnetic Flux Transport on the Sun
Zhao, Junwei; Kosovichev, Alexander G.; Švanda, Michal
We use the magnetic butterfly diagram to determine the speed of the magnetic flux transport on the solar surface toward the poles. The manifestation of the flux transport is clearly visible as elongated structures extended from the sunspot belt to the polar regions. The slopes of these structures are measured and interpreted as meridional magnetic…
Hubble Space Telescope NICMOS Imaging Polarimetry of Proto-Planetary Nebulae. II. Macromorphology of the Dust Shell Structure via Polarized Light
Ueta, Toshiya; Meixner, Margaret; Murakawa, Koji
The structure of the dusty circumstellar envelopes (CSEs) of proto-planetary nebulae (PPNs) reveals the mass-loss history of these sources and how such histories may differ for elliptical (SOLE) and bipolar (DUPLEX) PPNs. To study the PPN structures via dust-scattered linearly polarized starlight, we have compiled the imaging-polarimetric data for…
XMM-Newton observation of the NLS1 galaxy Ark 564. I. Spectral analysis of the time-average spectrum
McHardy, I.; Papadakis, I. E.; Page, M. J. +2 more
Context: We present the results from the spectral analysis of the time-average spectrum of the Narrow Line Seyfert 1 (NLS1) galaxy Ark 564 from a ~100 ks XMM-Newton observation.
Aims: Our aim is to characterize accurately the shape of the time-average, X-ray continuum spectrum of the source and search for any emission and/or absorption feature…
X-ray and optical variability of Seyfert 1 galaxies as observed with XMM-Newton
Smith, R.; Vaughan, S.
We have examined simultaneous X-ray and optical light curves of a sample of eight nearby Seyfert 1 galaxies observed using the European Photon Imaging Camera (EPIC) X-ray cameras and Optical Monitor onboard XMM-Newton. The observations span ~1 d and revealed optical variability in four of the eight objects studied. In all the cases, the X-ray vari…
Velocity Structure in the Orion Nebula. I. Spectral Mapping in Low-Ionization Lines
Henney, W. J.; García-Díaz, Ma. T.
High-dispersion echelle spectroscopy in optical forbidden lines of O0, S+, and S2+ is used to construct velocity-resolved images and electron-density maps of the inner region of the Orion Nebula with a resolution of 10 km s-1×3''×2''. Among the objects and regions revealed in this s…
Hemisphere coupling in Enceladus' asymmetric plasma interaction
Saur, Joachim; Neubauer, Fritz M.; Schilling, Nico
The recently discovered neutral gas plume around the south pole of Enceladus introduces a pronounced north-south asymmetry in the plasma interaction of Saturn's magnetosphere with Enceladus. In this work we present an analytic model for such an asymmetric interaction for both an Alfvénic and a unipolar inductor far field model including the Hall e…
Small-Scale X-Ray/EUV Jets Seen in Hinode XRT and TRACE
Chae, Jongchul; Kim, Yeon-Han; Park, Young-Deuk +4 more
We present the morphological and kinematic characteristics of three small-scale X-ray/EUV jets simultaneously observed by the Hinode XRT and the TRACE. For this, we examined all XRT movies with a thin Al/Poly filter from 2006 October 20 to 2007 April 8, and then found 34 small-scale eruptions. We next took a look at the corresponding TRACE 171/195…