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Rapid Oscillations in Cataclysmic Variables. VIII. YY Draconis (=3A 1148+719

Caillault, J. -P.; Schwartz, D. A.; Williams, G. A. +3 more

A 16th magnitude cataclysmic variable presumably a dwarf nova, was detected near one of the positions permitted for the hard (2-10 keV) X-ray source 3A 1148 + 719. The optical and UV spectra of YY Dra are fairly typical of cataclysmic variables, except that the TiO absorption bands of an M dwarf can be seen for greater than 5000 A. This shows that…

Lyman-Alpha Emission in Star-forming Galaxies: Low-Redshift Counterparts of Primeval Galaxies?

Calzetti, D.; Kinney, A. L.

We present UV plus optical spectra of three galaxies, Mrk 496, Mrk 357, Tol 1924-416, obtained by matching the size of the optical aperture with that of IUE. From the Hα/Hβ ratios, we estimate values of E(B - V)-extinction due to dust-for the two Markarian galaxies which are higher than those derived in previous works. We have used the new values …

The 0623+71 Bow Shock Nebula

Feibelman, W. A.; Hollis, J. M.; Wagner, R. M. +1 more

Deep radio continuum and deep narrow-band optical emission-line images showing the cataclysmic variable 0623 + 71 engulfed in a bow shock morphology are presented. The limb-brightened H-alpha, forbidden N II and 6 cm radio continuum emission regions define the global nebular morphology, extending to much greater spatial distances than the apex-con…

Detection of a Proton Beam during the Impulsive Phase of a Stellar Flare

Robinson, Richard D.; Shore, Steven N.; Woodgate, Bruce E. +2 more

A transient event consistent with the predicted temporal and spectral signatures of an energetic proton beam was detected in the impulsive phase of a small flare on the red dwarf star AU Microscopii. It consisted of a prominent increase in the flux in the red wing of Lyman-alpha near 1223 A, simultaneously with the peak of a flare observed in the …

The Identification of Highly Ionized Metal Species in the Hot DA1 White Dwarf G191-B2B with the Hubble Space Telescope Faint Object Spectrograph

Sion, Edward M.; Bohlin, Ralph C.; Tweedy, Richard W. +1 more

On the Certification of AM Canum Venaticorum as a Cataclysmic Variable

Halpern, Jules P.; Raymond, John C.; Patterson, Joseph +1 more

The evidence that the peculiar faint blue star AM CVn (= HZ 29) is an ultrashort-period cataclysmic binary is reexamined. The existence of at least two noncommensurate short periods in the light curve, plus the recent discovery of the class of pulsating DB white dwarfs, suggests a need for reappraisal of the binary star model. New photometry and s…

Gravitational Lensing of Quasars as Seen by the Hubble Space Telescope Snapshot Survey

Maoz, D.; Lahav, O.; Schneider, D. P. +4 more

As part of the ongoing HST Snapshot Survey, 152 additional high- luminosity z > 1 quasars were observed, bringing the total to 184 quasars. Each exposure was searched for evidence of gravitational lensing. Only one quasar among those observed, 1208+1011, is a candidate lens system with subarcsecond image separation. Six other quasars have point…

New Calibrators for the Cepheid Period-Luminosity Relation

Evans, Nancy R.

IUE spectra of six Cepheids have been used to determine their absolute magnitudes from the spectral types of their binary companions. The stars observed are U Aql, V659 Cen, Y Lac, S Nor, V350 Sgr, and V636 Sco. The absolute magnitude for V659 Cen is more uncertain than for the others because its reddening is poorly determined and the spectral typ…

Deep Hubble Space Telescope Imaging of a Compact Radio Galaxy at Z = 2.390

Windhorst, Rogier; Keel, William C.; Mathis, Douglas F.

We present deep 4 hr HST/WFC images in V and I of the LBDS radio galaxy 53W002, a weak and compact narrow-line galaxy recently discovered at z = 2.390. After deconvolution, the resolution is 0.2" FWHM. Its I- band structure is quite compact with 30% +/- 10% of its flux in the central <~ 1 kpc, presumably from its AGN. This is surrounded by a cl…

Highly Ionized Atoms toward HD 93521

Fitzpatrick, Edward L.; Spitzer, Lyman, Jr.

Results are reported from the HST High Resolution Spectrograph observations of absorption features of C IV and Si IV in the spectrum of the high-latitude O star HD 93521 (l = 183 deg; b = 62 deg). A comparison of Si IV and C IV profiles showed that the FWHM of both features is about 50 km/sec, in contrast to the 7 km/sec found for one of the sever…