Search Publications

Variable Circumstellar Structure of Luminous Hot Stars: the Impact of Spectroscopic Long-term Campaigns

Kaufer, Andreas

The formation and evolution of galaxies.

Ellis, Richard

Galaxies represent the visible fabric of the Universe and there has been considerable progress recently in both observational and theoretical studies. The underlying goal is to understand the present-day diversity of galaxy forms, masses and luminosities. Popular models predict the bulk of the population assembled recently, in apparent agreement w…

Ultraviolet images of the gravitationally lensed quadruple quasar Q2237+0305 with the HST WFPC2

Turner, Edwin L.; Blanton, Michael; Wambsganss, Joachim

We present and analyse observations of the quadruple lensed quasar Q2237+0305, obtained with the HST WFPC2 camera in the F336W and F300W filters. 25 exposures were performed within 15h real time on 1995 November 3. On a time-scale of 3-4h, we observe no variation in component A greater than 0.02 mag. The other components remain constant over a per…

Number counts and redshift distribution of gravitational arclets as a probe of galaxy evolution

Pello, R.; Soucail, G.; Bezecourt, J.

We present a detailed model of the absolute number counts, color and redshift distributions of gravitational arclets observed in clusters of galaxies. The framework adopted for galaxy evolution is chosen to reproduce the observed number counts and redshift distribution of field galaxies. Then, a spectrophotometric evolutionary code is coupled with…

Assessment of Degradation of VIRGO Radiometers on Board SOHO

Finsterle, W.; Dewitte, S.; Anklin, M. +2 more

The Metal Absorption Systems of the Hubble Deep Field South QSO

Savaglio, Sandra

The Hubble Deep Field South (HDFS) has been recently selected, and the observations are planned for 1998 October. We present a high-resolution (FWHM ~= 14 km s^-1) spectrum of the quasar J2233-606 (z_em ~= 2.22), which is located 5.1‧ east of the HDFS. The spectrum obtained with the New Technology Telescope redward of the Lyalpha emission line cov…

Are solar granules the only source of acoustic oscillations?

Foglizzo, T.

The excitation mechanism of low degree acoustic modes is investigated through the analysis of the stochastic time variations of their energy. The correlation between the energies of two different modes is interpreted as the signature of the occurrence rate of their excitation source. The different correlations determined by Foglizzo etal (1998) co…

Epilogue: Cosmic Rays in the Active Heliosphere

Wibberenz, G.; Jokipii, J. R.

The lower main sequence of the globular cluster M3 with the Hubble Space Telescope: luminosity and mass functions

Montegriffo, P.; Paresce, F.; de Marchi, G. +6 more

We present HST observations of the lower main sequence of the Galactic globular cluster M3. Our data, obtained with WFPC2 in the F814W and F555W filters, sample a region centred about 4 arcmin away from the cluster centre (at ~4.2 core radii). The photometry of the WF2, WF3 and WF4 fields extends down to V~26.5 (I~25), much deeper than any previou…

Space Telescope Imaging Spectrograph Observations of the Interstellar Velocity Structure and Chemical Composition toward the Carina Nebula

Walborn, Nolan R.; Jenkins, Edward B.; Sembach, Kenneth R. +9 more

We have observed the O-type star CPD -59°2603 in the Carina Nebula with the Space Telescope Imaging Spectrograph near-UV and far-UV high-resolution echelles, at a resolving power of ~110,000 (FWHM) and S/N ~ 30. This sight line has complex velocity and excitation structure in the interstellar absorption lines, corresponding to three distinct regio…