Search Publications
Statistical Properties of Ultraluminous IRAS Galaxies from an HST Imaging Survey
Mao, S.; Cui, J.; Xia, X. -Y. +2 more
We perform photometric measurements on a large HST snapshot imaging survey sample of 97 ultraluminous infrared galaxies (ULIRGs). We select putative nuclei from bright clumps in all the sample targets, mainly based on a quantitative criterion of I-band luminosity as well as the global and local morphological information. All the sources are then c…
Unidentified Infrared Emission Bands in the Diffuse Interstellar Medium
Okumura, K.; Nakagawa, T.; Onaka, T. +7 more
Using the mid-infrared spectrometer on board the Infrared Telescope in Space and the low-resolution grating spectrometer (PHT-S) on board the Infrared Space Observatory, we obtained 820 mid-infrared (5-12 µm) spectra of the diffuse interstellar medium (DIM) in the Galactic center, W51, and Carina Nebula regions. These spectra indicate that t…
Screening the Hipparcos-based astrometric orbits of sub-stellar objects
Arenou, F.; Pourbaix, D.
The combination of Hipparcos astrometric data with the spectroscopic data of putative extrasolar planets seems to indicate that a significant fraction of these low-mass companions could be brown or M dwarfs (Han et al. \cite{Han-2001:a}). We show that this is due to the adopted reduction procedure, and consequently that the Hipparcos data do not r…
Stellar populations in NGC 5128 with the VLT: Evidence for recent star formation
Minniti, D.; Rejkuba, M.; Bedding, T. R. +1 more
We resolve stars of the nearest giant elliptical galaxy NGC 5128 using VLT with FORS1 and ISAAC. We construct deep U, V and Ks color-magnitude and color-color diagrams in two different halo fields (in the halo and in the north-eastern diffuse shell). In the outer, shell field, at ~ 14 kpc from the center of the galaxy, there is a signif…
The Tolman Surface Brightness Test for the Reality of the Expansion. IV. A Measurement of the Tolman Signal and the Luminosity Evolution of Early-Type Galaxies
Sandage, Allan; Lubin, Lori M.
We review a sample of the early literature in which the reality of the expansion is discussed. Hubble's reluctance, even as late as 1953, to accept the expansion as real is explained as due to his use of equations for distances and absolute magnitudes of redshifted galaxies that do not conform to the modern Mattig equations of the standard model. …
Observational Tests and Predictive Stellar Evolution
Liebert, James; Mamajek, E. E.; Arnett, David +1 more
We compare 18 binary systems with precisely determined radii and masses from 23 to 1.1 Msolar and stellar evolution models produced with our newly revised code TYCHO. ``Overshooting'' and rotational mixing were suppressed in order to establish a baseline for isolating these and other hydrodynamic effects. Acceptable coeval fits are foun…
Detection of Coronal Mass Ejections in V471 Tauri with the Hubble Space Telescope
Bond, Howard E.; Sion, Edward M.; Mullan, D. J. +1 more
V471 Tauri, an eclipsing system consisting of a hot DA white dwarf (WD) and a dK2 companion in a 12.5 hr orbit, is the prototype of the precataclysmic binaries. The late-type component is magnetically active, due to its being constrained to rotate synchronously with the short orbital period. During a program of ultraviolet spectroscopy of V471 Tau…
Distant Cluster Hunting: A Comparison Between the Optical and X-Ray Luminosity Functions from an Optical/X-Ray Joint Survey
Dickinson, Mark; Mack, Jennifer; Donahue, Megan +6 more
We present a comparison of X-ray and optical luminosities and luminosity functions of cluster candidates from a joint optical/X-ray survey, the ROSAT Optical X-Ray Survey. Completely independent X-ray and optical catalogs of 23 ROSAT fields (4.8 deg2) were created by a matched-filter optical algorithm and by a wavelet technique in the X…
The problem of the Pleiades distance. Constraints from Strömgren photometry of nearby field stars
Stello, D.; Nissen, P. E.
The discrepancy between the Pleiades cluster distance based on Hipparcos parallaxes and main sequence fitting is investigated on the basis of Strömgren photometry of F-type stars. Field stars with the same metallicity as the Pleiades have been selected from the m1 index and a technique has been developed to locate the ZAMS of these fiel…
A new method for ISOCAM data reduction - I. Application to the European Large Area ISO Survey Southern Field: method and results
Aussel, H.; Pozzi, F.; Danese, L. +7 more
We develop a new data reduction technique for ISOCAM LW data and apply it to the European Large Area ISO Survey (ELAIS) LW3 (15-µm) observations in the southern hemisphere (S1). This method, known as LARI technique and based on the assumption of the existence of two different time-scales in ISOCAM transients (accounting for either fast or sl…