Search Publications
Cassini Visual and Infrared Mapping Spectrometer Observations of Iapetus: Detection of CO2
Sotin, C.; Brown, R. H.; Baines, K. H. +26 more
The Visual and Infrared Mapping Spectrometer (VIMS) instrument aboard the Cassini spacecraft obtained its first spectral map of the satellite Iapetus in which new absorption bands are seen in the spectra of both the low-albedo hemisphere and the H2O ice-rich hemisphere. Carbon dioxide is identified in the low-albedo material, probably a…
Sources of Oscillation Frequency Increase with Rising Solar Activity
Dziembowski, W. A.; Goode, P. R.
We analyze and interpret SOHO MDI data on oscillation frequency changes between 1996 and 2004, focusing on differences between the activity minimum and maximum of solar cycle 23. We study only the behavior of the centroid frequencies, which reflect changes averaged over spherical surfaces. Both the f-mode and p-mode frequencies are correlated with…
The B-Band Luminosity Function of Red and Blue Galaxies up to z = 3.5
Dickinson, M.; Fontana, A.; Cristiani, S. +5 more
We have explored the redshift evolution of the luminosity function of red and blue galaxies up to z=3.5. This was possible by joining a deep I-band composite galaxy sample, which includes the spectroscopic K20 sample and the Hubble Deep Field samples, with the deep HAB=26 and KAB=25 samples derived from the deep NIR images of…
Discovery of a Planetary-Mass Brown Dwarf with a Circumstellar Disk
Luhman, K. L.; Fazio, G. G.; Megeath, S. T. +4 more
Using the Hubble Space Telescope, the 4 m Blanco Telescope at the Cerro Tololo Inter-American Observatory, and the Spitzer Space Telescope, we have performed deep imaging from 0.8 to 8 µm of the southern subcluster in the Chamaeleon I star-forming region. In these data, we have discovered an object, Cha 110913-773444, whose colors and magnit…
A Systematic Search for Gravitationally Lensed Arcs in the Hubble Space Telescope WFPC2 Archive
Smith, Graham P.; Treu, Tommaso; Ellis, Richard S. +1 more
We present the results of a systematic search for gravitationally lensed arcs in clusters of galaxies located in the Hubble Space Telescope Wide Field and Planetary Camera 2 data archive. By carefully examining the images of 128 clusters we have located 12 candidate radial arcs and 104 tangential arcs, each of whose length-to-width ratio exceeds 7…
Simultaneous Ultraviolet and X-Ray Observations of Seyfert Galaxy NGC 4151. I. Physical Conditions in the X-Ray Absorbers
Gull, T. R.; Kriss, G. A.; Turner, T. J. +9 more
We present a detailed analysis of the intrinsic X-ray absorption in the Seyfert 1 galaxy NGC 4151 using Chandra High Energy Transmission Grating Spectrometer data obtained in 2002 May as part of a program that included simultaneous ultraviolet (UV) spectra using the Hubble Space Telescope Space Telescope Imaging Spectrograph and the Far Ultraviole…
UBVR and Hubble Space Telescope Mid-Ultraviolet and Near-Infrared Surface Photometry and Radial Color Gradients of Late-Type, Irregular, and Peculiar Galaxies
Windhorst, Rogier A.; Jansen, Rolf A.; Hibbard, John E. +2 more
We introduce a data set of 142 mostly late-type spiral, irregular, and peculiar (interacting or merging) nearby galaxies observed in UBVR at the Vatican Advanced Technology Telescope (VATT), and we present an analysis of their radial color gradients. We confirm that nearby elliptical and early- to mid-type spiral galaxies show either no or only sm…
X-Ray Observations of the Boundary Layer in Dwarf Novae at Low Accretion Rates
Pandel, Dirk; Mason, Keith O.; Córdova, France A. +1 more
We present a spectral analysis of XMM-Newton data of 10 dwarf novae, 9 of which were observed during a quiescent state. The X-ray spectra indicate the presence of a hot, optically thin plasma with a temperature distribution consistent with a simple, isobaric cooling flow. The likely origin of the X-ray emission is cooling plasma in the boundary la…
A Large X-Ray Outburst in Mira A
Wood, Brian E.; Schlegel, Eric; Raymond, John C. +2 more
We report the Chandra ACIS-S detection of a bright soft X-ray transient in the Mira AB interacting symbiotic-like binary. We have resolved the system for the first time in X-rays. Using Chandra and Hubble Space Telescope images, we determine that the unprecedented outburst is likely associated with the cool asymptotic giant branch (AGB) star, Mira…
Dynamical Masses for Low-Mass Pre-Main-Sequence Stars: A Preliminary Physical Orbit for HD 98800 B
Torres, Guillermo; Latham, David W.; Wasserman, Lawrence H. +7 more
We report on Keck Interferometer observations of the double-lined binary (B) component of the quadruple pre-main-sequence (PMS) system HD 98800. With these interferometric observations, combined with astrometric measurements made by the Hubble Space Telescope (HST) Fine Guidance Sensors (FGS) and published radial velocity observations, we have est…