Search Publications
Host Galaxies of Two Micron All Sky Survey-selected QSOs at Redshift over 0.3
Hutchings, J. B.; Cutri, R. M.; Cherniawsky, A. +1 more
We have obtained optical imaging with the Canada-France-Hawaii Telescope (CFHT) of 21 2MASS-selected QSOs of redshift greater than 0.3. This paper complements the sample of lower redshift 2MASS QSOs previously published. The QSOs have higher overall and nuclear luminosity, bluer colors, and higher ratio of nuclear to host flux than the lower redsh…
Characterizing three candidate magnetic cataclysmic variables from SDSS: XMM-Newton and optical follow-up observations.
Szkody, P.; Henden, A.; Schmidt, G. D. +4 more
In the latest in our series of papers on XMM-Newton and ground-based optical follow-up of new candidate magnetic cataclysmic variables (mCVs) found in the Sloan Digital Sky Survey, we report classifications of three systems: SDSS J144659.95+025330.3, SDSS J205017.84-053626.8, and SDSS J210131.26+105251.5. Both the X-ray and optical fluxes of SDSS …
Imprints of Environment on Cluster and Field Late-Type Galaxies at z~1
Ford, H. C.; Demarco, R.; Menanteau, F. +6 more
We present a comparison of late-type galaxies (Sa and later) in intermediate-redshift clusters and in the field using images from the Advanced Camera for Surveys aboard the Hubble Space Telescope. Cluster and field galaxies are selected by matching photometric and spectroscopic catalogs of four cluster fields: Cl 0152-1357, Cl 1056-0337 (MS 1054),…
The Astrometric-Spectroscopic Binary System HIP 50796: An Overmassive Companion
Torres, Guillermo
We report spectroscopic observations of the star HIP 50796, previously considered (but later rejected) as a candidate member of the TW Hya association. Our measurements reveal it to be a single-lined binary with an orbital period of 570 days and an eccentricity of e=0.61. The astrometric signature of this orbit was previously detected by Hipparcos…
Cool Customers in the Stellar Graveyard. III. Limits to Substellar Objects around nearby White Dwarfs using the Canada-France-Hawaii Telescope
Ge, Jian; Debes, John H.; Ftaclas, Christ
Results from a ground-based high-contrast imaging survey of 13 nearby white dwarfs for substellar objects are presented. We place strict upper limits on the type of substellar objects present, ruling out the presence of anything larger than ~14MJ for eight of the white dwarfs at separations >19 AU and corresponding to primordial sepa…
The Starburst-Interstellar Medium Interaction in NGC 1569. II. Small-Scale Examination of Nebular Emission, H II Region Size Distribution, and H II Region Luminosity Function
Kobulnicky, Henry A.; Buckalew, Brent A.
As the nearest dramatic example of a poststarburst galaxy driving a galactic wind, NGC 1569 is an ideal test environment to understand the impact of ``feedback'' from massive star lives and deaths on the surrounding interstellar medium. We present Hubble Space Telescope Wide Field Planetary Camera 2 narrowband imagery of NGC 1569 in an attempt to …
A Spectroscopic Study of the Star-Forming Properties of the Center of NGC 4194
Kaiser, M. E.; Weistrop, D.; Nelson, C. H. +1 more
We have obtained Space Telescope Imaging Spectrograph long-slit spectra of the central region of the advanced merger NGC 4194. The spectra cover the wavelength ranges 1150-1750 Å in the UV and 2900-10270 Å in the visible. Results from the study of the properties of 14 star-forming regions (knots) are presented. If the [N II] contribution is 40% of…
X-Ray Pulsations in the Supersoft X-Ray Binary CAL 83
Cowley, A. P.; Schmidtke, P. C.
Chandra and XMM-Newton X-ray data reveal that the supersoft X-ray binary CAL 83 exhibits 38.4 minute pulsations at some epochs. These X-ray variations are similar to those found in some novae and are likely to be caused by nonradial pulsations of the white dwarf. This is the first detection of pulsations in a classical supersoft X-ray binary.
CCD Speckle Observations of Binary Stars from the Southern Hemisphere. IV. Measures during 2001
Horch, Elliott P.; Franz, Otto G.; Baptista, Brian J. +1 more
We present 549 observations of 181 primarily southern binary stars. Of these, 32 are high-quality nondetections, meaning that, if binary, the system had a separation below the diffraction limit at the time of the observation, and relative astrometry is presented for the remaining 517 observations. In addition, a magnitude difference measure is rep…
Lyα Absorption in the Quasar Triplet Q0107-025A, Q0107-025B, and Q0107-0232: Data Calibration and Line Selection
Impey, C. D.; Petry, C. E.; Foltz, C. B. +1 more
We present spectroscopic observations for quasars Q0107-025A, Q0107-025B, and Q0107-0232. For the first time, all data obtained with the Hubble Space Telescope's GHRS and FOS for these three quasars are combined. Lyα absorbers selected from the spectra can be used to trace the coherence of the intergalactic medium (IGM) on scales of 1-2 h-1