Gaseous halos of nine nearby galaxies (with redshifts cz < 6000 km s) were probed at large galactocentric radii using background quasars observed with HST GHRS and STIS. The projected quasar-galaxy separations range from 55 to 387 h 75 kpc. Lyα absorption lines were successfully detected in the spectra

We present phase-resolved spectroscopy of AM Herculis obtained with the HST/GHRS when the system was in a high state. The ultraviolet light curve shows a quasi-sinusoidal modulation, which can be explained by a hot spot on the rotating white dwarf. The broad Lyα absorption expected for photospheric radiation of a moderately hot white dwarf is largely filled in with emission. The UV/FUV spectrum...

We present a simple, e†ective approach for estimating the on-order backgrounds of spectra taken with the highest resolution modes of the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope. Our scheme for determining the on-order background spectrum for STIS E140H and E230H observations uses moderate-order polynomial Ðts to the interorder scattered light visible in t...

Comet Hyakutake (C/1996 B2) provided a target of opportunity for performing a systematic study of water photodissociation products in which we obtained data from three instruments on the Hubble Space T elescope (HST ). The HST Goddard High Resolution Spectrograph (GHRS) was used to measure the line proÐle of hydrogen Lya (H Lya) at six locations around the coma of the comet, ranging from the nu...

Recent HST/GHRS observations of the z = 0.7010 absorber toward the QSO 1718+4807 (selected because of apparently ideal characteristics for measuring D/H) yield a D/H significantly higher D/H than some recent high-redshift measurements. Our analysis indicates D/H = 1.8 − 2.5 × 10 −4. This may indicate a cosmological inhomogeneity in the deuterium abundance of at least a factor of ten.

We have obtained spectra of the yellow giant S1040 in the open cluster M67 using the Goddard High-Resolution Spectrograph (GHRS) and the Faint Object Spectrograph on the Hubble Space Telescope. S1040 is a single-lined spectroscopic binary with a 42.8d period that occupies a “red straggler” position in the M67 color-magnitude diagram (CMD), 0.2 mag blueward of the giant branch. A detection of S1...

Research about recommender systems emerges over the last decade and comprises valuable services to increase different companies' revenue. Several approaches exist in handling paper systems. While most existing rely either on a content-based approach or collaborative approach, there are hybrid that can improve recommendation accuracy using combination of both approaches. Even though many algorit...

We present HST-GHRS observations of four stars in search of β Pictoris-like circumstellar gaseous disks. We detected gas around HR 10, HR 2174 and 51 Oph at large distances from the stars; this gas is circumstellar since the absorption lines from very excited levels require densities incompatible with those found in the diffuse interstellar medium. The shape of the lines and the Mg ii doublet r...

BACKGROUND The hallmark of neurofibromatosis type 1 (NF1) is the development of multiple neurofibromas. Solitary neurofibroma may occur in an individual who does not have NF1, but multiple neurofibromas tend to develop only in those with NF1. It has been suggested that hormones may influence the neurofibromas of patients with NF1. The evidence that hormones may influence the growth of neurofibr...