Search Publications
Dust and Extinction Curves in Galaxies with z>0: The Interstellar Medium of Gravitational Lens Galaxies
Peng, C. Y.; Keeton, C. R.; Kochanek, C. S. +6 more
We determine 37 differential extinctions in 23 gravitational lens galaxies over the range 0<~zl<~1. Only seven of the 23 systems have spectral differences consistent with no differential extinction. The median differential extinction for the optically selected (radio-selected) subsample is ΔE(B-V)=0.04 (0.06) mag. The extinction i…
Fundamental parameters of nearby stars from the comparison with evolutionary calculations: masses, radii and effective temperatures
Allende Prieto, C.; Lambert, D. L.
The Hipparcos mission has made it possible to constrain the positions of nearby field stars in the colour-magnitude diagram with very high accuracy. These positions can be compared with the predictions of stellar evolutionary calculations to provide information on the basic parameters of the stars: masses, radii, effective temperatures, ages, and …
NICMOS Imaging of the HR 4796A Circumstellar Disk
Schneider, Glenn; Hines, Dean C.; Terrile, Richard J. +7 more
We report the first near-infrared (NIR) imaging of a circumstellar annular disk around the young (~8 Myr), Vega-like star HR 4796A. NICMOS coronagraph observations at 1.1 and 1.6 µm reveal a ringlike symmetrical structure that peaks in reflected intensity 1.05"+/-0.02" (~70 AU) from the central A0 V star. The ring geometry, with an inclinati…
The ROSAT all-sky survey catalogue of the nearby stars
Schmitt, J. H. M. M.; Sterzik, M. F.; Voges, W. +1 more
We present X-ray data for all entries of the Third Catalogue of Nearby Stars \cite[(Gliese & Jahreiss 1991)]{gli91} that have been detected as X-ray sources in the ROSAT all-sky survey. The catalogue contains 1252 entries yielding an average detection rate of 32.9 percent. In addition to count rates, source detection parameters, hardness ratio…
A High Merger Fraction in the Rich Cluster MS 1054-03 at Z = 0.83: Direct Evidence for Hierarchical Formation of Massive Galaxies
van Dokkum, Pieter G.; Franx, Marijn; Kelson, Daniel D. +2 more
We present a morphological study of the galaxy population of the luminous X-ray cluster MS 1054-03 at z=0.83. The sample consists of 81 spectroscopically confirmed cluster members in a 3×2 h-150 Mpc area imaged in F606W and F814W with WFPC2. We find 13 ongoing mergers in MS 1054-03, comprising 17% of the L>~L* c…
Slow Magnetosonic Waves in Coronal Plumes
Nakariakov, V. M.; DeForest, C. E.; Ofman, L.
Recent observations of polar plumes in the southern solar coronal hole by the Extreme-Ultraviolet Imaging Telescope (EIT) on board the SOHO spacecraft show signatures of quasi-periodic compressional waves with periods of 10-15 minutes. The relative wave amplitude was found to increase with height in the plumes up to about 1.2 Rsolar. Us…
Mapping the contours of the Local bubble: preliminary results
Crifo, F.; Lallement, R.; Welsh, B. Y. +1 more
We present preliminary results from a long-term program of mapping the neutral absorption characteristics of the local interstellar medium, taking advantage of Hipparcos stellar distances. Equivalent widths of the NaI D-line doublet at 5890 Å are presented for the lines-of-sight towards some 143 new target stars lying within 300 pc of the Sun. Usi…
Open clusters with Hipparcos. I. Mean astrometric parameters
Arenou, F.; Robichon, N.; Turon, C. +1 more
New memberships, mean parallaxes and proper motions of all 9 open clusters closer than 300 pc (except the
Active region EUV transient brightenings - First Results by EIT of SOHO JOP 80
Berghmans, D.; Clette, F.
On 13 May 1998, the Extreme-Ultraviolet Imaging Telescope (EIT, on board SOHO) has produced a unique image sequence operating in 'shutterless mode' (SOHO JOP 80). In JOP 80, EIT is the lead instrument, followed by several space-born instruments (SXT, TRACE, MDI, CDS, SUMER), as well as two observatories on the ground (in La Palma and Sac Peak). Th…
ISOCAM observations of the Hubble Deep Field reduced with the PRETI method
Aussel, H.; Elbaz, D.; Cesarsky, C. J. +1 more
We have developed a new ISOCAM data reduction technique based on wavelet analysis, especially designed for the detection of faint sources in mid-infrared surveys. This method, the Pattern REcognition Technique for Isocam data (PRETI) has been used to reduce the observations of the Hubble Deep Field (HDF) and flanking fields with ISOCAM at 6.75 (LW…