FUSE Observations of Galactic and Intrinsic Absorption in the Spectrum of the Seyfert 1 Galaxy 2MASX J21362313-6224008

We present the far-ultraviolet spectrum of the Seyfert 1 galaxy 2MASX J21362313-6224008 obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE). The spectrum features absorption from Galactic OVI at two velocities and redshifted HI Lyman beta and gamma, CII, CIII, and O VI. The redshifted absorption features represent a single kinematic component blueshifted by ~310 km/s relative to the AGN. We use photoionization models to derive constraints on the physical parameters of the absorbing gas. An alternative interpretation for the absorption lines is also proposed, whereby the absorbing gas is associated with an intervening galaxy cluster.Comment: Astrophysical Journal, in pres

An Extended FUSE Survey of Diffuse O VI Emission in the Interstellar Medium

We present a survey of diffuse O VI emission in the interstellar medium obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE). Spanning 5.5 years of FUSE observations, from launch through 2004 December, our data set consists of 2925 exposures along 183 sight lines, including all of those with previously-published O VI detections. The data were processed using an implementation of CalFUSE v3.1 modified to optimize the signal-to-noise ratio and velocity scale of spectra from an aperture-filling source. Of our 183 sight lines, 73 show O VI 1032 emission, 29 at > 3-sigma significance. Six of the 3-sigma features have velocities |v_LSR| > 120 km/s, while the others have |v_LSR| < 50 km/s. Measured intensities range from 1800 to 9100 LU, with a median of 3300 LU. Combining our results with published O VI absorption data, we find that an O VI-bearing interface in the local ISM yields an electron density n_e = 0.2--0.3 cm^-3^ and a path length of 0.1 pc, while O VI-emitting regions associated with high-velocity clouds in the Galactic halo have densities an order of magnitude lower and path lengths two orders of magnitude longer. Though the O VI intensities along these sight lines are similar, the emission is produced by gas with very different properties.Comment: 27 pages, 16 figures, accepted by Ap

A New Analysis of the O VI Emitting Nebula around KPD 0005+5106

We present observations of O VI 1032 emission around the helium white dwarf KPD 0005+5106 obtained with the Far Ultraviolet Spectroscopic Explorer. Previously published data, reprocessed with an updated version of the calibration pipeline, are included along with new observations. The recent upward revision of the white dwarf's effective temperature to 200,000 K has motivated us to re-analyze all the data. We compare observations with photoionization models and find that the density of the O VI nebula is about 10 cm^-3, and that the stellar flux must be attenuated by about 90% by the time it impinges on the inner face of the nebula. We infer that this attenuation is due to circumstellar material ejected by KPD 0005+5106 earlier in its evolution.Comment: 21 pages, including 3 figures and 2 tables. Accepted for publication in the Astrophysical Journal. Minor change: a few uncited references remove

Discovery of an OVI Emitting Nebula around the Hot White Dwarf KPD 0005+5106

A survey of diffuse interstellar sight lines observed with the Far Ultraviolet Spectroscopic Explorer has led to the serendipitous discovery of a high-ionization nebula around the hot white dwarf KPD 0005+5106. The nebula has an OVI 1032A surface brightness of up to 25,000 photons/s/cm^2/sr, making it the brightest region of extended OVI emission in our survey. Photoionization models using the incident white dwarf continuum successfully reproduce the observed OVI intensity. The OVI emission arises in the highly ionized inner region of a planetary nebula around KPD 0005+5106. This newly discovered nebula may be one member of a class of high-ionization planetary nebulae that are difficult to detect in the optical, but which can be easily identified in the ultraviolet.Comment: accepted for publication in ApJL, 11 pages including 2 figure

FUSE Detection of Galactic OVI Emission in the Halo above the Perseus Arm

Background observations obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) toward l=95.4, b=36.1 show OVI 1032,1038 in emission. This sight line probes a region of stronger-than-average soft X-ray emission in the direction of high-velocity cloud Complex C above a part of the disk where Halpha filaments rise into the halo. The OVI intensities, 1600+/-300 ph/s/cm^2/sr (1032A) and 800+/-300 ph/s/cm^2/sr (1038A), are the lowest detected in emission in the Milky Way to date. A second sight line nearby (l=99.3, b=43.3) also shows OVI 1032 emission, but with too low a signal-to-noise ratio to obtain reliable measurements. The measured intensities, velocities, and FWHMs of the OVI doublet and the CII* line at 1037A are consistent with a model in which the observed emission is produced in the Galactic halo by hot gas ejected by supernovae in the Perseus arm. An association of the observed gas with Complex C appears unlikely.Comment: accepted for publication in ApJL, 11 pages including 3 figure

The Rapidly Rotating, Hydrogen Deficient, Hot Post-Asymptotic Giant Branch Star ZNG 1 in the Globular Cluster M5

We report observations of the hot post-asymptotic giant branch star ZNG 1 in the globular cluster M5 (NGC 5904) with the Far Ultraviolet Spectroscopic Explorer (FUSE). From the resulting spectrum, we derive an effective temperature T_eff = 44300 +/- 300 K, a surface gravity log g = 4.3 +/- 0.1, a rotational velocity v sin i = 170 +/- 20 km/s, and a luminosity log (L/L_sun) = 3.52 +/- 0.04. The atmosphere is helium-rich (Y = 0.93), with enhanced carbon (2.6% by mass), nitrogen (0.51%) and oxygen (0.37%) abundances. The spectrum shows evidence for a wind with terminal velocity near 1000 km/s and an expanding shell of carbon- and nitrogen-rich material around the star. The abundance pattern of ZNG 1 is suggestive of the ``born-again'' scenario, whereby a star on the white-dwarf cooling curve undergoes a very late shell flash and returns to the AGB, but the star's rapid rotation is more easily explained by a previous interaction with a binary companion.Comment: 8 pages, 2 PostScript figures, Latex with emulateapj5. Accepted for publication in ApJ Letter

Final Calibration of the Berkeley Extreme and Far-Ultraviolet Spectrometer on the ORFEUS-SPAS I and II Missions

The Berkeley Extreme and Far-Ultraviolet Spectrometer (BEFS) flew as part of the ORFEUS telescope on the ORFEUS-SPAS I and II space-shuttle missions in 1993 and 1996, respectively. The data obtained by this instrument have now entered the public domain. To facilitate their use by the astronomical community, we have re-extracted and re-calibrated both data sets, converted them into a standard (FITS) format, and placed them in the Multimission Archive at Space Telescope (MAST). Our final calibration yields improved wavelength scales and effective-area curves for both data sets.Comment: To appear in the January 2002 issue of the PASP. 17 pages with 9 embedded postscript figures; uses emulateapj5.st