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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
The GM Values of Mimas and Tethys and the Libration of Methone
Porco, C. C.; Jacobson, R. A.; Spitale, J. +1 more
We have determined the GM of the Saturnian satellite Mimas from an analysis of its resonance with Tethys and with the newly discovered satellite Methone (GM is the product of the Newtonian constant of gravitation G and the satellite's mass M). Observations of the latter permit a factor of 5 improvement in our knowledge of Mimas's GM; its value is …
Dynamical Masses of the Components in o Andromedae
Cvetković, Z.; Olević, D.
It has been shown in earlier papers that o And is a quadruple star. Based on spectroscopic observations, Hill and coworkers calculated the orbital elements for a binary, assigning it to the B component. We have calculated the orbital elements for the subsystems Aa-B and Aa using speckle interferometry measurements. The individual masses of the o A…
An Inverse Look at the Center of M15
Chakrabarty, Dalia
The observed radial and transverse velocities of individual stars in the globular cluster M15 are used as inputs to a fully nonparametric code (CHASSIS) in order to estimate the equilibrium stellar distribution function and the three-dimensional mass density profile, from which are estimated the mass-to-light ratio, enclosed mass, and velocity dis…
Faint U-Band Dropouts in the WFPC2 Parallels of the Hubble Ultra Deep Field
Casertano, Stefano; de Mello, Duilia; Wadadekar, Yogesh
We combine data from the extremely deep Hubble Space Telescope U (F300W) image, obtained using WFPC2 as part of the parallel observations of the Hubble Ultra Deep Field campaign, with BVi images from the Great Observatories Origins Deep Survey to identify a sample of Lyman break galaxies in the redshift range 2.0<~z<~3.5. We use recent stell…
VI Photometry of Globular Clusters NGC 6293 and NGC 6541: The Formation of the Metal-poor Inner Halo Globular Clusters
Lee, Jae-Woo; Carney, Bruce W.
We present VI photometry of the metal-poor inner halo globular clusters NGC 6293 and NGC 6541 using the WFPC2 on board the Hubble Space Telescope (HST). Our color-magnitude diagrams of the clusters show well-defined blue horizontal-branch populations, consistent with their low metallicities and old ages. NGC 6293 appears to have blue straggler sta…
The Algol System XX Cephei
Angione, Ronald J.; Sievers, John R.
We present new five-color photometric and spectroscopic observations of the Algol system XX Cephei (V=9.13, P=2.3 days). This system is known to have a variable period. From analysis of both the period variations and the light curve we found no support for apsidal motion. However, there is a possible light-time effect. The period changes could als…
Fourier Analysis of Hubble Space Telescope Fine Guidance Sensor Data of Binary Stars and Application to the Multiple System HD 157948
Wasserman, Lawrence H.; Horch, Elliott P.; Franz, Otto G. +1 more
A Fourier-based method is presented for the analysis of binary and multiple star data taken with the Hubble Space Telescope Fine Guidance Sensors (FGSs). Relative astrometry and magnitude differences are obtained as with standard FGS analysis techniques, and although the FGS system is essentially unfiltered, this method also permits the characteri…
An X-Ray Observation of the L1251 Dark Cloud
Simon, Theodore
An X-ray image of the L1251 dark cloud in Cepheus was obtained with the XMM-Newton telescope. More than three dozen sources were detected above a 3 σ limit in X-ray luminosity of LX=1029.0 ergs s-1. Among the detections are eight optically visible T Tauri stars, which had been identified in earlier work from their …