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The mass ratio of Charon to Pluto from Hubble Space Telescope astrometry with the fine guidance sensors
Olkin, C. B.; Franz, O. G.; Wasserman, L. H.
The mass ratio of Charon to Pluto is a basic parameter describing the binary system and is necessary for determining the individual masses and densities of these two bodies. Previous measurements of the mass ratio have been made, but the solutions differ significantly (Null et al., 1993; Young et al., 1994; Null and Owen, 1996; Foust et al., 1997;…
Detection of Pulsed X-Ray Emission from XMM-Newton Observations of PSR J0538+2817
Cropper, M.; McGowan, K. E.; Kennea, J. A. +5 more
We report on the XMM-Newton observations of the 143 ms pulsar PSR J0538+2817. We present evidence for the first detections of pulsed X-rays from the source at a frequency that is consistent with the predicted radio frequency. The pulse profile is broad and asymmetric, with a pulse fraction of 18%+/-3%. We find that the spectrum of the source is we…
Active Star Formation in the N11B Nebula in the Large Magellanic Cloud: A Sequential Star Formation Scenario Confirmed
Barbá, Rodolfo H.; Rubio, Mónica; Roth, Miguel R. +1 more
The second largest H II region in the Large Magellanic Cloud, N11B has been surveyed in the near-IR. We present JHKs images of the N11B nebula. These images are combined with CO (1-->0) emission-line data and with archival New Technology Telescope and Hubble Space Telescope WFPC2 optical images to address the star formation activity …
Galaxies under the Cosmic Microscope: A Gemini Multiobject Spectrograph Study of Lensed Disk Galaxy 289 in A2218
Smail, I.; Kneib, J. -P.; Smith, Graham P. +7 more
In this paper, we exploit the gravitational potential of the rich cluster A2218 as a magnifying glass. We demonstrate that the magnification due to the cluster allows us to observe distant background galaxies at a comparable level of detail to galaxies at z~0.1. Using the Gemini Multiobject Spectrograph (GMOS) integral field unit (IFU) on Gemini N…
Ultraviolet Spectroscopy of Narrow Coronal Mass Ejections
Raymond, J. C.; Dobrzycka, D.; Biesecker, D. A. +2 more
We present Ultraviolet Coronagraph Spectrometer (UVCS) observations of five narrow coronal mass ejections (CMEs) that were among 15 narrow CMEs originally selected by Gilbert and coworkers. Two events (1999 March 27, April 15) were ``structured,'' i.e., in white-light data they exhibited well-defined interior features, and three (1999 May 9, May 2…
The 2001 April Burst Activation of SGR 1900+14: X-Ray Afterglow Emission
Hurley, K.; Costa, E.; Mereghetti, S. +8 more
After nearly two years of quiescence, the soft gamma-ray repeater SGR 1900+14 again became burst-active on 2001 April 18, when it emitted a large flare, preceded by few weak and soft short bursts. After having detected the X- and gamma-prompt emission of the flare, BeppoSAX pointed its narrow field X-ray telescopes to the source in less than 8 hr.…
Mid-IR emission of galaxies in the Virgo cluster III. The data
Sauvage, M.; Boselli, A.; Gavazzi, G. +2 more
We present ISOCAM imaging data at 6.75 and 15 mu m for 145 galaxies in the Virgo cluster and in the Coma/A1367 supercluster. Of these, 99 form a complete, optically-selected, volume-limited sample including galaxies in the core and in the periphery of the Virgo cluster, suitable for statistical analysis. 34 of the Virgo galaxies were resolved by I…
A Scattered Light Echo around SN 1993J in M81
Bregman, Joel N.; Seitzer, Patrick; Liu, Ji-Feng
A light echo around SN 1993J was observed 8.2 yr after explosion by a Hubble Space Telescope Wide Field Planetary Camera 2 observation, adding to the small family of supernovae with light echoes. The light echo was formed by supernova light scattered from a dust sheet that lies 220 pc away from the supernova, 50 pc thick along the line of sight, a…
The Line Emission Region in III Zw 2: Kinematics and Variability
Bon, E.; Popović, L. Č.; Mediavilla, E. G. +2 more
We have studied the Lyα, Hβ, Hα, and Mg II λ2798 line profiles of the Seyfert 1 galaxy III Zw 2. The shapes of these broad emission lines show evidence of a multicomponent origin and also features that may be identified as the peaks due to a rotating disk. We have proposed a two-component broad-line region (BLR) model consisting of an inner Kepler…
X-ray spectroscopy of the cluster of galaxies PKS 0745-191 with XMM-Newton
Böhringer, H.; Chen, Y.; Ikebe, Y.
We present the results from XMM-Newton observations of the cluster of galaxies