Search Publications
Solar irradiances of UV and EUV lines during the minimum of the sunspot activity in 1996
Wilhelm, K.; Curdt, W.; Schühle, U. +6 more
Full Sun observations in UV and EUV emission lines were performed by SUMER (Solar Ultraviolet Measurements of Emitted Radiation) on SOHO (Solar and Heliospheric Observatory) in 1996. The radiometric preflight calibration of SUMER is traceable to a primary radiometric source standard - the electron storage ring BESSY. Based on this calibration and …
Candidate high-redshift and primeval galaxies in Hubble Deep Field South
Clements, D. L.; Eales, S. A.; Baker, A. C.
We present the results of colour selection of candidate high-redshift galaxies in Hubble Deep Field South (HDF-S) using the Lyman dropout scheme. The HDF-S data we discuss were taken in a number of different filters extending from the near-UV (F300W) to the infrared (F222M) in two different fields. This allows us to select candidates with redshift…
Geneva photometry of the Be star HR 1960: periodicity and extremely small amplitude
Burki, G.
The Be star HR 1960 has been monitored from 1982 to 1998 in Geneva photometry and from November 1989 to March 1993 by the Hipparcos satellite. This star shows two kinds of luminosity variation: i) The mean luminosity in V has slightly increased, by 5 millimags, during the survey (long-term variation); ii) A periodic light variation with a period o…
Working Group 4 Report: Composition and Elemental Abundance Variations in the Solar Atmosphere and Solar Wind
Bochsler, Peter; Mason, Helen E.
This paper contains a summary of the topics treated in the working group on abundance variations in the solar atmosphere and in the solar wind. The FIP bias (overabundance of particles with low First Ionization Potentials over photospheric abundances) in coronal holes and coronal hole associated solar wind amounts to values between 1 and 2. The FI…
Constraints on Coronal Outflow Velocities Derived from UVCS Doppler Dimming Measurements and in-Situ Charge State Data
Romoli, M.; Dobrzycka, D.; Biesecker, D. A. +6 more
We constrain coronal outflow velocity solutions, resolved along the line-of-sight, by using Doppler dimming models of H I Lyman alpha and O VI 1032/1037 Å emissivities obtained with data from the Ultraviolet Coronagraph Spectrometer (UVCS) on SOHO. The local emissivities, from heliocentric heights of 1.5 to 3.0 solar radii, were determined from 3-…
Old, Low-Mass, Metal-Rich (SMR) Stars
Soubiran, C.; Lebreton, Y.; Cayrel de Strobel, G. +1 more
The authors of this paper try to disentangle the many problems arisen from a new enlarged sample of nearby low-mass,metal-rich-stars. These stars have reliable absolute magnitudes, deduced from Hipparcos parallaxes, precise bolometric corrections, effective temperatures and metal abundances from high resolution detailed spectroscopic analyses. The…
Observations of GRBs with the Infrared Space Observatory
Altieri, B.; Piro, L.; Palazzi, E. +17 more
We present results from the Target of Opportunity (TOO) program to observe GRB locations with the CAM and PHOT instruments aboard the Infrared Space Observatory (ISO). Four BeppoSAX/ GRB error circles were observed by ISO on timescales ranging from days to months after the GRB events. These observations represent the first prompt GRB counterpart s…
The Role of Reconnection in the Formation of Flux Ropes in the Solar Wind
Gosling, J. T.
New magnetic loops formed in the corona beneath coronal mass ejections, CMEs, provide strong evidence that magnetic reconnection commonly occurs within the magnetic `legs' of the departing CMEs. Such reconnection is inherently 3-dimensional and produces a magnetic flux rope structure within a CME. Depending upon how far reconnection proceeds, the …
Coronal Heating by Magnetic Explosions
Falconer, D. A.; Moore, R. L.; Porter, J. G. +1 more
From magnetic fields and coronal heating observed in flares, active regions, quiet regions, and coronal holes, we propose that exploding sheared core magnetic fields are the drivers of most of the dynamics and heating of the solar atmosphere, ranging from the largest and most powerful coronal mass ejections and flares, to the vigorous microflaring…
Results from the GOLF instrument on SOHO
Baudin, F.; García, R. A.; Pallé, P. L. +9 more
An 800 day series of GOLF velocity data, with uniquely high continuity and stability, offers the best ever signal to noise ratio obtained in global Sun observations. Following meticulous efforts to provide reliable calibration, these data have been used for measurements of frequencies, line-widths and power in the p-modes, which are used for inver…