Search Publications
Solar Energetic Particle Production by Coronal Mass Ejection-driven Shocks in Solar Fast-Wind Regions
Kahler, S. W.; Reames, D. V.
Gradual solar energetic particle (SEP) events at 1 AU are produced by coronal/interplanetary shocks driven by coronal mass ejections (CMEs). Fast (vCME>~900 km s-1) CMEs might produce stronger shocks in solar slow-wind regions, where the flow and fast-mode MHD wave speeds are low, than in fast-wind regions, where those spe…
Gemini-Phoenix infrared high-resolution abundance analysis of five giants in the bulge globular cluster NGC 6553
Zoccali, M.; Bica, E.; Barbuy, B. +4 more
A detailed abundance analysis of 5 giants of the metal-rich bulge globular cluster NGC 6553 was carried out using high resolution infrared spectra in the H band, obtained at the Gemini-South 8m telescope. JK photometry collected at ESO and VI photometry from the Hubble Space Telescope are used to derive effective temperatures. The present analysis…
Vertical distribution of Galactic disk stars. II. The surface mass density in the Galactic plane
Soubiran, C.; Siebert, A.; Bienaymé, O.
High resolution spectral data of red clump stars towards the NGP have been obtained with the high resolution spectrograph Elodie at OHP for Tycho-2 selected stars. Combined with Hipparcos local analogues, we determine both the gravitational force law perpendicular to the Galactic plane and the total surface mass density and thickness of the Galact…
Bashful ballerina: Southward shifted heliospheric current sheet
Mursula, K.; Hiltula, T.
It is known since long [Rosenberg and Coleman, 1969] that one of the two sectors of the interplanetary magnetic field (IMF) observed at the Earth's orbit dominates at high heliographic latitudes during solar minimum times, reflecting the poloidal structure of the global solar magnetic field at these times. Here we find that while this latitudinal …
Joint observations of propagating oscillations with SOHO/CDS and TRACE
Marsh, M. S.; De Moortel, I.; Ireland, J. +1 more
Joint Observing Program (JOP) 83 Solar and Heliospheric Observatory/Coronal Diagnostic Spectrometer (SOHO/CDS) and Transition Region and Coronal Explorer (TRACE) data is analysed for evidence of propagating intensity oscillations along loop structures in the solar corona. A propagating intensity oscillation with a minimum estimated speed of 50-195…
Does M15 Possess an Intermediate-Mass Black Hole in Its Core?
Anderson, J.; Harrison, T. E.; McNamara, B. J.
We present the results of an internal proper motion analysis of the inner region of M15 using Hubble Space Telescope Wide Field Planetary Camera 2 images. The motions of 704 stars with brightnesses above that of the cluster turnoff (V<18.3) are analyzed to determine the velocity dispersion profile within about 15" of the cluster center. The ave…
Local Surface Density of the Galactic Disk from a Three-Dimensional Stellar Velocity Sample
Girard, T. M.; Korchagin, V. I.; van Altena, W. F. +2 more
We have reestimated the surface density of the Galactic disk in the solar neighborhood within +/-0.4 kpc of the Sun using the parallaxes and proper motions of a kinematically and spatially unbiased sample of 1476 old bright red giant stars from the Hipparcos catalog with measured radial velocities from Barbier-Brossat & Figon. We determine the…
First-look XMM-Newton EPIC observations of the prototypical starburst galaxy M82
Stevens, Ian R.; Bravo-Guerrero, Jimena; Read, Andrew M.
We present initial XMM-Newton EPIC observations of the prototypical starburst galaxy M82. The superwind is seen to extend continuously from the starburst region to the X-ray emission associated with the Hα`cap'. We also find evidence for a ridge feature, probably associated with the superwind interacting with an HI streamer. Narrow-band images, ce…
Fe K emission and absorption features in XMM-Newton spectra of Markarian 766: evidence for reprocessing in flare ejecta
O'Brien, P. T.; Reeves, J. N.; Page, K. L. +2 more
We report on the analysis of a long XMM-Newton European Photon Imaging Camera (EPIC) observation in 2001 May of the narrow-line Seyfert 1 galaxy Markarian 766 (Mrk 766). The 3-11 keV spectrum exhibits a moderately steep power-law continuum, with a broad emission line at ~6.7 keV, probably blended with a narrow line at ~6.4 keV, and a broad absorpt…
Long period variables detected by ISO in the Small Magellanic Cloud
Blommaert, J. A. D. L.; Omont, A.; van Loon, J. Th. +8 more
This article presents the study of the light-curves extracted from the MACHO database of a sample of stars observed by the Infrared Space Observatory in the Small Magellanic Cloud. These stars belong to the ISO-Mini-Survey catalogue of the Magellanic Clouds (ISO-MCMS, Loup et al. {in preparation}). Most of them are in the asymptotic giant branch (…