Search Publications
Probing AGB nucleosynthesis via accurate Planetary Nebula abundances
Pottasch, S. R.; Tielens, A. G. G. M.; Marigo, P. +2 more
The elemental abundances of ten planetary nebulae, derived with high accuracy including ISO and IUE spectra, are analysed with the aid of synthetic evolutionary models for the TP-AGB phase. The accuracy on the observed abundances is essential in order to make a reliable comparison with the models. The advantages of the infrared spectra in achievin…
On the nature of moving magnetic feature pairs around sunspots
Solanki, S. K.; Zhang, Jun; Wang, Jingxiu
Employing data recorded by the Michelson Doppler Imager (MDI) instrument on the Solar and Heliospheric Observatory (SOHO), we have identified 144 pairs of opposite magnetic polarity moving magnetic features (MMFs) in two active regions (NOAA ARs 8375 and 9236). The following results are obtained: (1) The majority of MMF pairs first appears at a di…
Compositions of Saturn's rings A, B, and C from high resolution near-infrared spectroscopic observations
Poulet, F.; French, R. G.; Cruikshank, D. P. +2 more
We used the NASA IRTF spectrograph SpeX to obtain near-infrared spectra (0.9-5.4 mu m) of Saturn's rings, achieving spectral resolution lambda / Delta lambda of about 2000. The spatial resolution (about 1 arcsec) is sufficient to distinguish the three main ring components (A, B and C rings) from one another. These new observations of Saturn's ring…
Gas-phase CO2 toward massive protostars
van Dishoeck, E. F.; Lahuis, F.; Doty, S. D. +1 more
We present infrared spectra of gas-phase CO2 around 15 mu m toward 14 deeply embedded massive protostars obtained with the Short Wavelength Spectrometer on board the Infrared Space Observatory. Gas-phase CO2 has been detected toward 8 of the sources. The excitation temperature and the gas/solid ratio increase with the tempera…
An EUV Bright Point as seen by SUMER, CDS, MDI and EIT on-board SoHO
Doyle, J. G.; Madjarska, M. S.; Teriaca, L. +1 more
This paper presents the formation, evolution and decay of a coronal bright point via a spectroscopic analysis of its transition region counterpart and the evolution of the underlying magnetic bipole during 3 days of almost continuous observations. The data were obtained with various instruments on-board SoHO, including the SUMER spectrograph in th…
The manifold spectra and morphologies of EROs
Cimatti, A.; Daddi, E.; Franceschini, A. +13 more
Deep VLT optical spectroscopy, HST+ACS (GOODS) imaging and VLA observations are used to unveil the nature of a complete sample of 47 EROs with R-Ks>5 and Ks<20. The spectroscopic redshift completeness is 62%. Morphological classification was derived for each ERO through visual inspection and surface brightness profile f…
High resolution soft X-ray spectroscopy of the elliptical galaxy NGC 5044. Results from the reflection grating spectrometer on-board XMM-Newton
Kaastra, J. S.; Tamura, T.; Makishima, K. +1 more
The results from an X-ray spectroscopic study of the giant elliptical galaxy NGC 5044 in the center of a galaxy group are presented. The line dominated soft X-ray spectra (mainly Fe-L and O Viii Lyalpha ) from the diffuse gas are resolved for the first time in this system with the Reflection Grating Spectrometers on-board XMM-Newton and provide a …
First identification and modelling of SPI background lines
Knödlseder, J.; Schönfelder, V.; Diehl, R. +17 more
On Oct. 17, 2002, the ESA INTEGRAL observatory was launched into a highly elliptical orbit. SPI, a high resolution Ge spectrometer covering an energy range of 20-8000 keV, is one of its two main instruments. We use data recorded early in the mission (i.e. in March 2003) to characterize the instrumental background, in particular the many gamma-ray …
ISOCAM view of the starburst galaxies M 82 , NGC 253 and NGC 1808
Förster Schreiber, N. M.; Sauvage, M.; Vigroux, L. +4 more
We present results of mid-infrared lambda = 5.0-16.5 µm spectrophotometric imaging of the starburst galaxies
Distances to nearby galaxies around IC 342
Dolphin, A. E.; Grebel, E. K.; Sharina, M. E. +1 more
We present an analysis of Hubble Space Telescope/WFPC2 images of six nearby galaxies in the projected vicinity of IC 342: Cas dSph, KK 35, UGCA 86, Cam A, NGC 1560, and Cam B. We derive distances to five of them from the luminosity of the tip of the red giant branch stars with a typical accuracy of ~ 10%. The galaxy distances are 0.79 Mpc (Cas dSp…