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Metal Abundances in the Magellanic Stream
Shull, J. Michael; Stocke, John T.; Gibson, Brad K. +3 more
We report on the first metallicity determination for gas in the Magellanic Stream, using archival Hubble Space Telescope (HST) GHRS data for the background targets Fairall 9, III Zw 2, and NGC 7469. For Fairall 9, using two subsequent HST revisits and new Parkes multibeam narrowband observations, we have unequivocally detected the MS I H I compone…
Hubble Space Telescope Studies of the WLM Galaxy. II. The Star Formation History from Field Stars
Dolphin, Andrew E.
HST F555W and F814W photometry of a portion of the WLM galaxy is presented. The distance modulus is determined via fitting of the entire color-magnitude diagram to be (m-M)0=24.88+/-0.09, which is consistent with the red giant branch tip distance. The galaxy's measurable star formation history appears to have begun no more than 12 Gyr a…
Detection of the extra-Galactic background fluctuations at 170 mu m
Lagache, G.; Puget, J. L.
We have used the Marano1 field observations with ISOPHOT at 170 mu m to search for the Cosmic Far-InfraRed Background fluctuations. This field is part of the FIRBACK project (Puget et al. 1999). For the first time, fluctuations due to unresolved extra-Galactic sources are isolated. The emission of such sources clearly dominates, at arcminute scale…
Resolved Spectroscopy of the Narrow-Line Region in NGC 1068. III. Physical Conditions in the Emission-Line Gas
Crenshaw, D. Michael; Kraemer, Steven B.
The physical conditions in the inner narrow-line region (NLR) of the Seyfert 2 galaxy NGC 1068 are examined using ultraviolet and optical spectra and photoionization models. The spectra were taken with the Hubble Space Telescope Space Telescope Imaging Spectrograph (STIS), through the 0.1"×52.0" slit, covering the full STIS 1200-10000 Å waveband. …
Caltech Faint Galaxy Redshift Survey. IX. Source Detection and Photometry in the Hubble Deep Field Region
Steidel, Charles C.; Hogg, David W.; Neugebauer, Gerry +6 more
Detection and photometry of sources in the Un, G, \Rscr, and Ks bands in a 9×9 arcmin2 region of the sky, centered on the Hubble Deep Field, are described. The data permit construction of complete photometric catalogs to roughly Un=25, G=26, \Rscr=25.5, Ks=20 mag and significant photometric me…
Identification of Spectral Lines in the 500-1600 Å Wavelength Range of Highly Ionized Ne, Na, Mg, Ar, K, Ca, Ti, Cr, Mn, Fe, Co, and Ni Emitted by Flares (Te>=3×106 K) and Their Potential Use in Plasma Diagnostics
Wilhelm, K.; Curdt, W.; Landi, E. +1 more
On 1999 May 9 the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrometer on the Solar and Heliospheric Observatory (SOHO) recorded spectra from a high-temperature region located in the solar corona above the west limb. These spectra contain lines from rather less-abundant elements in solar plasmas. In this paper we present identi…
Radial Velocity Studies of Close Binary Stars. III
Rucinski, Slavek M.; Lu, Wenxian; Mochnacki, Stefan W.
Radial velocity measurements and simple sine-curve fits to the orbital velocity variations are presented for the third set of 10 close binary systems: CN And, HV Aqr, AO Cam, YY CrB, FU Dra, RZ Dra, UX Eri, RT LMi, V753 Mon, and OU Ser. All systems except two (CN And and RZ Dra) are contact, double-line spectroscopic binaries, with four of them (Y…
High Angular Resolution Determination of Extinction in the Orion Nebula
O'Dell, C. R.; Yusef-Zadeh, F.
The optical appearance of the Orion Nebula is significantly altered by the presence of interstellar extinction. Since Orion is high above the Galactic plane and is nearby, most of this extinction is due to material immediately in front of the associated star cluster. This extinction fundamentally alters the optical appearance of the Orion Nebula. …
Elemental composition of the inner source pickup ions
Geiss, J.; Schwadron, N. A.; Zurbuchen, T. H. +2 more
Observations of the composition of inner source pickup ions in the solar wind, from the Solar Wind Ion Composition Spectrometer on Ulysses, are presented. The composition is similar to that of the solar wind and, in particular, contains volatile elements such as neon. These observations suggest strongly, and perhaps conclusively, that inner source…
The ortho:para-H_2 ratio in C- and J-type shocks
Pineau des Forêts, G.; Cabrit, S.; Flower, D. R. +1 more
We have computed extensive grids of models of both C- and J-type planar shock waves, propagating in dark, cold molecular clouds, in order to study systematically the behaviour of the ortho:para-H_2 ratio. Careful attention was paid to both macroscopic (dynamical) and microscopic (chemical reactions and collisional population transfer in H_2) aspec…