Search Publications
Abundances of planetary nebulae NGC 40 and NGC 6153
Pottasch, S. R.; Beintema, D. A.; Feibelman, W. A. +1 more
The ISO and IUE spectra of the elliptical nebulae NGC 40 and NGC 6153 are presented. These spectra are combined with the spectra in the visual wavelength region to obtain a complete, extinction corrected, spectrum. The chemical composition of the nebulae is then calculated and compared to previous determinations. A discussion is given of: (1) the …
A deep 6.7 mu m survey in the SSA13 field with ISO
Sanders, D. B.; Kawara, K.; Taniguchi, Y. +8 more
We present results of a deep mid-infrared survey in the SSA13 field with the Infrared Space Observatory (ISO). In order to probe the near-infrared light at high redshifts, we surveyed the field with the broad band LW2 (5-8.5 mu m) filter of the mid-infrared camera ISOCAM. Adopting a highly redundant imaging strategy for the 23 h observation and ca…
X-ray emission line gas in the LINER galaxy M 81
Page, M. J.; Branduardi-Raymont, G.; Zane, S. +5 more
We present the soft X-ray spectrum of the LINER galaxy M 81 derived from a long observation with the XMM-Newton RGS. The spectrum is dominated by continuum emission from the active nucleus, but also contains emission lines from Fe L, and H-like and He-like N, O, and Ne. The emission lines are significantly broader than the RGS point-source spectra…
A multi-wavelength test of the FR I-BL Lac unifying model
Capetti, A.; Chiaberge, M.; Celotti, A. +2 more
We collect multi-wavelength measurements of the nuclear emission of 20 low luminosity FR I radio-galaxies to test the viability of the FR I-BL Lac unifying model. Although poorly sampled, the Spectral Energy Distributions (SED) of FR Is are consistent with the double peaked shape characteristic of BL Lacs. Furthermore while the distribution of the…
Far UV spectroscopy of the circumstellar environment of the Herbig Be stars HD 259431 and HD 250550
Deleuil, M.; Bouret, J. -C.; Catala, C. +2 more
We present an analysis of FUSE spectra of HD 259431 and HD 250550, two young Herbig Be stars. Numerous absorption lines of H_2 are seen in the spectrum of each star, revealing large amounts of this gas on the lines of sight. In addition, absorption lines from atomic species in different ionization and excitation states are also identified. We demo…
UV(IUE) spectra of hot post-AGB candidates
Parthasarathy, M.; Gauba, G.
Analysis of the low resolution UV(IUE) spectra (1150 to 3200 Å) of 15 hot post-AGB candidates is presented. The UV(IUE) spectra of 10 stars suggest partial obscuration of the hot stars due to circumstellar dust. The reddened continua of these 10 stars were used to model and estimate the circumstellar extinction. The circumstellar extinction law wa…
ISO-SWS calibration and the accurate modelling of cool-star atmospheres. II. General results
Eriksson, K.; Gustafsson, B.; Decin, L. +5 more
The fine calibration of the ISO-SWS detectors (Infrared Space Observatory - Short Wavelength Spectrometer) has proven to be a delicate problem. We therefore present a detailed spectroscopic study in the 2.38-12 mu m wavelength range of a sample of 16 A0-M2 stars used for the calibration of ISO-SWS. By investigating the discrepancies between the IS…
Mid- to far-infrared spectroscopy of Sharpless 171
Okada, Y.; Onaka, T.; Shibai, H. +1 more
We have collected one-dimensional raster-scan observations of the active star-forming region Sharpless 171 (S171), a typical H Ii region-molecular cloud complex, with the three spectrometers (LWS, SWS, and PHT-S) on board ISO. We have detected 8 far-infrared fine-structure lines, [O Iii] 52 mu m, [N Iii] 57 mu m, [O I] 63 mu m, [O Iii] 88 mu m, [N…
The FERRUM Project: Experimental transition probabilities of [Fe II] and astrophysical applications
Lundberg, H.; Johansson, S.; Hartman, H. +9 more
We report on experimental transition probabilities for thirteen forbidden [Fe II] lines originating from three different metastable Fe Ii levels. Radiative lifetimes have been measured of two metastable states by applying a laser probing technique on a stored ion beam. Branching ratios for the radiative decay channels, i.e. M1 and E2 transitions, …
Tomography of a stellar X-ray corona: alpha Coronae Borealis
Mewe, R.; Audard, M.; Güdel, M. +1 more
We interpret the X-ray light curve obtained by XMM-Newton during a total X-ray eclipse in the nearby binary star