Search Publications
IRAS 04296+3429: a 21 MU M source with a very strong 30 MU M emission band
Henning, Th.; Szczerba, R.; Cox, P. +2 more
We report the detection of the 30 mu m emission feature from the C-rich post-Asymptotic Giant Branch (post-AGB) star IRAS 04296+3429 based on ISO SWS observations. ISO data show that there is a clear substructure in the 30 mu m feature in the form of a plateau which extends from 26 to 27 mu m. This is confirmed by the ISO SWS data for another post…
The mass function of M 4 from near IR and optical HST observations
Paresce, Francesco; de Marchi, Guido; Pulone, Luigi
Deep images of the galactic globular cluster M 4 taken at various locations with the NIC 3 and the WFPC 2 cameras on HST were used to derive detailed local optical and near IR luminosity functions. White dwarfs have been detected for the first time on a color sequence at constant luminosity in the F110W band. Transformation of the observed luminos…
A classical approach to faint extragalactic source extraction from ISOCAM deep surveys. Application to the Hubble Deep Field
Abergel, A.; Bernard, J. -P.; Clements, D. L. +4 more
We have developed a general data reduction technique for ISOCAM data coming from various deep surveys of faint galaxies. In order to reach the fundamental limits of the camera (due to the background photon noise and the readout noise), we have devised several steps in the reduction processes that transform the raw data to a sky map which is then u…
A determination of the outflow speeds in the lower solar wind
Simnett, G. M.; Tappin, S. J.; Lyons, M. A.
The acceleration of the low-latitude solar wind, which comes from regions of the corona above large, closed magnetic loops, is a theoretical challenge. Until recently we have lacked direct measurements close to the Sun with which to constrain the theory. When a series of high-resolution coronagraph images is viewed in the form of a movie the conti…
Intensity oscillations in a sunspot plume
Fludra, A.
Observations of a sunspot plume (a compact feature, bright in the transition region line of O V 629.7 Angstroms at 2.2 x 10(5) K), seen above a sunspot in the active region AR8249, have been made with a 15-second time resolution with the Coronal Diagnostic Spectrometer on SOHO. Intensity of the O V 629.7 Angstroms line in the sunspot plume oscilla…
A deep 12 micron survey with ISO
Cesarsky, C.; Clements, D. L.; Reach, W. T. +4 more
We present the first results of a study of faint 12 mu m sources detected with the Infrared Space Observatory (ISO) in four deep, high galactic latitude fields. The sample includes 50 such sources in an area of 0.1 square degrees down to a 5sigma flux limit of ~ 500 mu Jy. From optical identifications based on the US Naval Observatory (USNO) catal…
The circumstellar environment of UX ORI
Prusti, T.; Thi, W. F.; Natta, A. +3 more
This paper presents new observations of UX Ori obtained with the millimeter interferometer of Plateau de Bure and with ISO. UX Ori is the prototype of a group of pre-main-sequence, intermediate-mass stars, often indicated as precursors of beta Pic. The interferometry observations at 1.2 and 2.6 mm show that UX Ori has a circumstellar disk, with ou…
Interstellar oxygen in the heliospheric interface: influence of electron impact ionization
Geiss, J.; Lallement, R.; Izmodenov, V. V.
A fraction of the interstellar atoms crosses the interface between the solar wind and the ionized component of the local interstellar medium (the heliospheric interface), and enters the heliosphere. The number of penetrating atoms depends on the strength of the atom-plasma interaction, i.e. on the atom type. In this paper we consider the penetrati…
Late A-type stars: new Strömgren photometric calibrations of absolute magnitudes from HIPPARCOS
Figueras, F.; Domingo, A.
Hipparcos trigonometric parallaxes have been used to derive a photometric absolute magnitude calibration of main-sequence late A-type stars in terms of Strömgren photometric indices - accounting for temperature, evolution and metallicity effects - and projected equatorial rotational velocities. The derived calibrations are valid for main-sequence …
Radiation scattering in the solar corona
Noci, G.; Maccari, L.
This paper discusses the scattering in the solar corona of the radiation emitted by the solar disk. We obtain expressions for the emissivity which permit to deduce the spectral characteristics of the scattered radiation. With these expressions, assuming a Maxwellian distribution for the velocities of the scattering ions and a simple spectral shape…