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The Chemical Evolution of the Galactic Disk - Part One - Analysis and Results
Gustafsson, B.; Andersen, J.; Lambert, D. L. +3 more
A Catalog of Intracluster Gas Temperatures
Forman, W.; Jones, C.; Vrtilek, S. D. +3 more
We have searched the Einstein Monitor Proportional Counter (MPC) data base for observations of clusters of galaxies. The MPC was a nonfocal plane instrument on board the Einstein Observatory and accumulated data during all pointed observations with the four focal plane instruments. By co-adding the MPC spectra obtained during all pointed observati…
Discovery of New Objects in the Orion Nebula on HST Images: Shocks, Compact Sources, and Protoplanetary Disks
O'Dell, C. R.; Wen, Zheng; Hu, Xihai
We have reduced and analyzed a set of narrow-band HST images of a portion of M42 south of the Trapezium. Many new emission-line sources were found, some quite long but so narrow that they are not seen on ground-based images. These include thin shells which are high-ionization shocks. The structure around Orion HH 3 is resolved into multiple compon…
The ultraviolet to soft X-ray bump of Seyfert 1 type active galactic nuclei.
Walter, R.; Fink, H. H.
The soft X-ray (0.1 - 2.4 keV) emission of 58 Seyfert type active galactic nuclei have been studied using the spectra obtained during the ROSAT all sky survey. These spectra are well represented by power law models with photon indices ranging between 1.6 and 3.4. The spectra usually do not show intrinsic absorption. A notable exception is Mrk 766 …
An Atlas of Ultraviolet Spectra of Star-forming Galaxies
Panagia, N.; Calzetti, D.; Wyse, Rosemary F. G. +2 more
An atlas of ultraviolet spectra of the central regions of 143 spiral, irregular, blue compact, Seyfert 2, and starburst galaxies is produced by combining 387 low-resolution spectra from the IUE data archives. The spectra have been extracted with an optimal algorithm and co-added to produce spectra with the best possible signal-to-noise ratio. Our …
Discovery of Jovian dust streams and interstellar grains by the Ulysses spacecraft
Forsyth, R.; Balogh, A.; Bame, S. J. +20 more
ON 8 February 1992, the Ulysses spacecraft flew by Jupiter at a distance of 5.4 AU from the Sun. During the encounter, the spacecraft was deflected into a new orbit, inclined at about 80° to the ecliptic plane, which will ultimately lead Ulysses over the polar regions of the Sun1. Within 1 AU from Jupiter, the onboard dust de…
SN 1991bg: A Type IA Supernova With a Difference
Suntzeff, N. B.; Walker, A. R.; Caldwell, Nelson +28 more
We present 13 spectra and 31 photometric observations covering the first 150 days of SN 1991bg in NGC 4374 (M 84). Although SN 1991bg was a type Ia supernova displaying the characteristic Si II absorption at 6150 A near maximum and the Fe emission lines at late phases, it varied from the well-defined norm for SNe Ia in several important respects. …
Hubble Space Telescope Discovery of Candidate Young Globular Clusters in the Merger Remnant NGC 7252
Robert, Carmelle; Leitherer, Claus; Whitmore, Bradley C. +2 more
New, high-resolution images of the central region of NGC 7252 obtained with the Planetary Camera of the Hubble Space Telescope are presented. NGC 7252 (sometimes referred to as the "Atoms-for-Peace" Galaxy) is a prototypical example of a remnant of two merged disk galaxies. Our most striking result is the discovery of a population of about 40 blue…
Goddard High-Resolution Spectrograph Observations of the Local Interstellar Medium and the Deuterium/Hydrogen Ratio along the Line of Sight toward Capella
Ayres, Thomas R.; Savage, Blair D.; Brown, Alexander +6 more
HST Goddard High-Resolution Spectrograph observations of the 1216, 2600, and 2800 A spectral regions are analyzed for the spectroscopic binary system Capella, obtained at orbital phase 0.26 with 3.27-3.57 km/s resolution and high SNR. The column densities of H I, D I, Mg II, and Fe II for the local interstellar medium along this 12.5 pc line of si…
Detection of Interstellar Pick-Up Hydrogen in the Solar System
Balsiger, H.; Geiss, J.; Galvin, A. B. +6 more
Interstellar hydrogen ionized primarily by the solar wind has been detected by the SWICS instrument on the Ulysses spacecraft at a distance of 4.8 astronomical units from the sun. This "pick-up" hydrogen is identified by its distinct velocity distribution function, which drops abruptly at twice the local solar wind speed. From the measured fluxes …