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Surface abundances of light elements for a large sample of early B-type stars - II. Basic parameters of 107 stars
Lambert, David L.; Lyubimkov, Leonid S.; Rostopchin, Sergey I. +1 more
Effective temperatures Teff, surface gravities logg and interstellar extinctions AV are found for 107 B stars. Distances d of the stars, which are based on the derived Teff, logg and AV values, show good agreement with those obtained from the Hipparcos parallaxes. Comparing the Teff and logg v…
The X-ray afterglows of gamma-ray bursts GRB 001025A and GRB 010220 observed with XMM-Newton
Santos-Lleó, M.; Ehle, M.; Watson, D. +5 more
The X-ray afterglows of GRB 001025A and GRB 010220 were detected by XMM-Newton with an average 0.2-10.0 keV flux of 4.4 and 3.3*E-14 erg cm-2 s-1 respectively; the afterglow of GRB 001025A is observed to decay. Afterglows at other wavelengths were not detected for either burst. A set of broadened soft X-ray emissio…
Observations of hyperluminous infrared galaxies with the Infrared Space Observatory: implications for the origin of their extreme luminosities
McMahon, Richard; Verma, Aprajita; Rowan-Robinson, Michael +1 more
We present 7-180 µm photometry of a sample of hyperluminous infrared galaxies (HyLIGs) obtained with the photometer and camera mounted on the Infrared Space Observatory. We have used radiative transfer models of obscured starbursts and dusty torii to model their spectral energy distributions (SEDs). We find that IRAS F00235+1024, IRAS F14218…
Far-Ultraviolet Spectroscopic Explorer Observations of the Magellanic Bridge Gas toward Two Early-Type Stars: Molecules, Physical Conditions, and Relative Abundances
Lehner, N.
We discuss Far Ultraviolet Spectroscopic Explorer (FUSE) observations of two early-type stars, DI 1388 (l=291.3d, b=-41.1d) and DGIK 975 (l=287.3d, b=-36.0d), in the low-density and low-metallicity (Z~0.08 Zsolar) gas of the Magellanic Bridge (MB). The data have a spectral resolution of about 15,000, and signal-to-noise ratios range bet…
QSO 2237+0305 VR Light Curves from Gravitational LensES International Time Project Optical Monitoring
Surdej, J.; Serra-Ricart, M.; Muñoz, J. A. +12 more
We present VR observations of QSO 2237+0305 conducted by the Gravitational Lensing International Time Project collaboration from 1999 October 1 to 2000 February 3. The observations were made with the 2.56 m Nordic Optical Telescope at Roque de los Muchachos Observatory, La Palma (Spain). The point-spread function (PSF) fitting method and an adapte…
The First Detections of the Extragalactic Background Light at 3000, 5500, and 8000 Å. II. Measurement of Foreground Zodiacal Light
Madore, Barry F.; Freedman, Wendy L.; Bernstein, Rebecca A.
We present a measurement of the absolute surface brightness of the zodiacal light (3900-5100 Å) toward a fixed extragalactic target at high ecliptic latitude based on moderate-resolution (~1.3 Å pixel-1) spectrophotometry obtained with the du Pont 2.5 m Telescope at the Las Campanas Observatory in Chile. This measurement and contemporan…
The Ratio of Blue to Red Supergiants in Sextans A from Hubble Space Telescope Imaging
Skillman, Evan D.; Dohm-Palmer, Robbie C.
We have examined the ratio of blue to red supergiants (B/R) in the dwarf irregular galaxy Sextans A. The supergiants were identified in previously published stellar photometry measured from Hubble Space Telescope imaging. The high-resolution imaging and low-dust environment provided high photometric accuracy such that the main sequence and blue he…
Modelling interplanetary CMEs using magnetohydrodynamic simulations
Schmidt, J. M.; Cargill, P. J.
The dynamics of Interplanetary Coronal Mass Ejections (ICMEs) are discussed from the viewpoint of numerical modelling. Hydrodynamic models are shown to give a good zero-order picture of the plasma properties of ICMEs, but they cannot model the important magnetic field effects. Results from MHD simulations are shown for a number of cases of interes…
Are Coronal Loops Isothermal?
Schmelz, J. T.
A controversy over the temperature distribution of coronal loops has arisen recently because different investigators using different techniques have obtained very different answers. Analysis of Solar and Heliospheric Observatory (SOHO) Extreme ultraviolet Imaging Telescope (EIT) and Transition Region and Coronal Explorer (TRACE) data using narrowb…
The Relative Ages of the Globular Cluster Subpopulations in M87
Jordán, Andrés; Marzke, Ronald O.; Côté, Patrick +1 more
Relative ages for the globular cluster (GC) subpopulations in the Virgo giant elliptical galaxy M87 (NGC 4486) have been determined from Strömgren photometry obtained with the Wide Field Planetary Camera 2 on board the Hubble Space Telescope. Using a variety of population synthesis models, and assuming the GC mass at the turnover of the luminosity…