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A Multiwavelength Study of PSR B0628-28: The First Overluminous Rotation-powered Pulsar?
Becker, Werner; Jessner, Axel; Kramer, Michael +2 more
The ROSAT source RX J0630.8-2834 was suggested by positional coincidence to be the X-ray counterpart of the pulsar PSR B0628-28. This association, however, was regarded to be unlikely on the basis of the computed energetics of the putative X-ray counterpart. In this paper we report on multiwavelength observations of PSR B0628-28 made with the ESO …
Discovery of Multiple Coaxial Rings in the Quadrupolar Planetary Nebula NGC 6881
Kwok, Sun; Su, Kate Y. L.
We report the discovery of multiple two-dimensional rings in the quadrupolar planetary nebula NGC 6881. As many as four pairs of rings are seen in the bipolar lobes, and three rings are seen in the central torus. While the rings in the lobes have the same axis as one pair of the bipolar lobes, the inner rings are aligned with the other pair. The t…
Supersolar Metallicity in the NLS1 Galaxy Markarian 1044
Pogge, Richard W.; Nicastro, Fabrizio; Mathur, Smita +3 more
We present measurements of the metallicity of the circumnuclear gas in the narrow-line Seyfert 1 (NLS1) galaxy Markarian 1044 using O VI column density measurements from the Far Ultraviolet Spectroscopic Explorer (FUSE) together with C IV, N V, and H I measurements from the Hubble Space Telescope (HST). From the absorption lines we find that the c…
Water clouds and dust aerosols observations with PFS MEX at Mars
Grigoriev, A.; Lellouch, E.; Piccioni, G. +18 more
Observations of water ice clouds and dust are among the main scientific goals of the Planetary Fourier Spectrometer (PFS), a payload instrument of the European Mars Express mission. We report some results, obtained in three orbits: 37, 41 and 68. The temperature profile, and dust and water ice cloud opacities are retrieved from the thermal infrare…
The Lens Galaxy in PG 1115+080 is an Ellipse
Kochanek, Christopher S.; Falco, Emilio E.; Yoo, Jaiyul +1 more
We use the structure of the Einstein ring image of the quasar host galaxy in the four-image quasar lens PG 1115+080 to determine the angular structure of the gravitational potential of the lens galaxy. We find that it is well described as an ellipsoid and that the best-fit nonellipsoidal models are consistent with the ellipsoidal model. We find up…
The Reverse Shock of SNR 1987A at 18 Years after Outburst
Smith, Nathan; Zhekov, Svetozar A.; Heng, Kevin +3 more
We use low-dispersion spectra obtained at the Magellan Observatory to study the broad Hα emission from the reverse shock of the infant supernova remnant SNR 1987A. These spectra demonstrate that the spatiokinematic structure of the reverse shock can be distinguished from that of the circumstellar ring and hot spots, even at ground-based spatial re…
Periodic variability during the X-ray decline of 4U 1636-53
Charles, P. A.; Bird, A. J.; Cornelisse, R. +2 more
We report the onset of a large amplitude, statistically significant periodicity (~46 d) in the Rossi X-ray Timing Explorer/All Sky Monitor (RXTE/ASM) data of the prototype X-ray burster 4U 1636-53, the X-ray flux of which has been gradually declining over the last 4 yr. This behaviour is remarkably similar to that observed in the neutron star low …
Stellar Populations in the Wing of the Small Magellanic Cloud from Hubble Space Telescope Photometry
Garnett, Donald R.; Dufour, Reginald J.; McCumber, Michael P.
We have used the Wide Field Planetary Camera 2 on the Hubble Space Telescope to image a star field in the wing of the Small Magellanic Cloud (SMC), near the H II region N81. The images were taken in the F336W, F547M, F675W, and F814W filters. From photometry of stars in this field, we construct color-magnitude diagrams (CMDs) for about 4200 stars …
The Nuclear Disk in the Dwarf Elliptical Galaxy NGC 4486A
Gebhardt, Karl; Kormendy, John; Sparks, W. B. +3 more
Many ellipticals contain nuclear disks of dust and gas. Some ellipticals contain nuclear disks of stars that are distinct from the rest of the galaxy. We show that the dwarf E2 galaxy NGC 4486A contains both-it is a ``Rosetta stone'' object that tells us how nuclear disks evolve. Its properties suggest that, as accreted gas dissipates and settles …
On the 3-dimensional structure of the streamer belt of the solar corona
Llebaria, A.; Zhukov, A. N.; Lamy, P. +1 more
We investigate the three-dimensional structure of the streamer belt of the solar corona using a model that allows us to simulate its quasi-stationary configuration. Starting from the National Solar Observatory photospheric magnetograms, the position of the neutral line at the source surface (2.5 ~R_⊙) is determined using the potential field source…