Search Publications
The Calibration of the Hubble Space Telescope Kuiper Belt Object Search: Setting the Record Straight
Stern, S. Alan; Levison, Harold F.; Tamblyn, Peter +2 more
The limiting magnitude of the Hubble Space Telescope (HST) data set used by Cochran and coworkers in 1995 to detect small objects in the Kuiper belt is reevaluated, and the methods used are described in detail. It is shown, by implanting artificial objects in the original HST images and rereducing the images using our original algorithm, that the …
A Photometric and Spectrophotometric Study of MR Cygni
Hubeny, I.; Linnell, A. P.; Etzel, P. B. +1 more
A self-consistent, physically accurate program suite has been used in an accurate simulation of new spectroscopy and photometry of MR Cygni. Analysis of both the spectroscopic and photometric data used spectrum synthesis techniques and a synthetic photometry augmentation of a light synthesis program package. The theoretical light curves closely fi…
Discovery of a 6.4 Micron Dust Feature in Hydrogen-Poor Planetary Nebulae
Borkowski, Kazimierz J.; Bregman, Jesse D.; Tsvetanov, Zlatan I. +2 more
Hydrogen-poor planetary nebulae (PNe) Abell 58, Abell 78, and IRAS 15154-5258 were observed with the ISOPHOT low-resolution spectrometer on board the Infrared Space Observatory. Polycyclic aromatic hydrocarbon (PAH) features, commonly seen in H II regions, PNe, and in the diffuse interstellar medium, are absent from their infrared (IR) spectra. A …
Simultaneous Hubble Space Telescope/Rossi X-Ray Timing Explorer Observations of Scorpius X-1
Kallman, T.; Boroson, B.; Vrtilek, S. D.
Scorpius X-1 is the brightest extrasolar point source of X-rays and may serve as a prototype for low-mass X-ray binaries as a class. It has been suggested that the UV and optical emission arise as a result of reprocessing of X-rays and that a likely site for such reprocessing is an accretion disk around the X-ray source. If UV and optical emission…
Observational Evidence for the Effect of Amplification Bias in Gravitational Microlensing Experiments
Han, Cheongho; Kim, Ho-Il; Jeong, Youngjin
Recently Alard, Mao, & Guibert and Alard proposed to detect the shift of a star's image centroid, δx, as a method to identify the lensed source among blended stars. Goldberg & Woźniak actually applied this method to the OGLE-1 database and found that seven of 15 events showed significant centroid shifts of δx >~ 0.2". The amount of cent…
Atomic Data and Spectral Line Intensities for Mg VIII
Bhatia, A. K.; Thomas, Roger J.
EUV spectral lines of Mg VIII have been observed from the solar corona by Skylab, SERTS, and more recently by SOHO. Atomic data for this astrophysically important ion are presented in this paper. The atomic data include energy levels, oscillator strengths, transition rates, and electron-impact excitation collision strengths. Twenty levels are incl…
ORFEUS II Far-Ultraviolet Observations of the Lunar Atmosphere
Flynn, B.
In 1996 November and December, remote FUV observations of the lunar atmosphere were conducted using the Berkeley spectrograph aboard the ORFEUS-SPAS II satellite. The main goal of the observations was to measure the distribution of Ar above the lunar dayside for the first time and to search for another predicted atmospheric constituent, Ne. During…
Ultraviolet Observations of the Hot R Coronae Borealis-Type Star V348 Sagittarii during a Deep Minimum
Clayton, Geoffrey C.; Jeffery, C. S.; Drilling, John S. +1 more
We obtained three high-quality ultraviolet spectra of the hot R Coronae Borealis type star V348 Sgr using the Faint Object Spectrograph of the Hubble Space Telescope (HST). The first of these spectra was obtained when the star was in a shallow minimum (ΔV less than 1 mag), whereas the other two were obtained during a deep minimum (ΔV ~ 6 mag). Whi…
A New Technique for Performing Two-Dimensional Spectroscopy of Objects of Large Dynamic Range: The Binary System HD 167605 A+B
Arribas, S.; Mediavilla, E.; Fuensalida, J. J.
We present a new technique for performing two-dimensional (integral-field) spectroscopy of objects with a large range in intensity. It is based on the capability of optical fibers to discretize the intensity distribution at the telescope focal plane. This allows not only reformatting but also the equalization of fiber output intensities, matching …
The Variable Central Star of PN G243.8-37.1
Peña, Miriam; Ruiz, María Teresa
Spectroscopic and photometric variations of the central star of the planetary nebula PRTM 1 (PN G243.8-37.1) have been detected from optical spectrophotometric data. The photometric variations can be as large as ΔV~1 mag, but most of the time they are within 0.2 mag. The phenomenon seems to be cyclic. These optical changes confirm the UV variation…