Search Publications
Physical parameters of sdB stars from spectral energy distributions
Jeffery, C. S.; Aznar Cuadrado, R.
The atmospheric parameters of 34 hot subdwarf B stars have been obtained using a combination of 61 short and long-wave IUE spectra, together with new and existing optical and infrared photometric data. Using a grid of high-gravity helium-deficient model atmospheres and a chi 2-minimization procedure, 15 single sdB stars and 19 composite…
Photoelectric effect on dust grains across the L1721 cloud in the rho Ophiuchi molecular complex
Boulanger, F.; Habart, E.; Pineau des Forêts, G. +3 more
We present ISO-LWS measurements of the main gas cooling lines, [C+] 158 mu m and [O0] 63 mu m towards a moderate opacity molecular cloud (Av ~ 3), L1721, illuminated by the B2 star nu Sco (chi = 5-10). These data are combined with an extinction map and IRAS dust emission images to test our understanding of gas heat…
XMM-Newton detection of a Comptonized accretion disc in the quasar PKS 0558-504
Dadina, M.; O'Brien, P. T.; Reeves, J. N. +6 more
We present XMM-Newton observations of the bright quasar PKS 0558-504. The 0.2-10 keV spectrum is dominated by a large, variable soft X-ray excess. The fastest flux variations imply accretion onto a Kerr black hole. The XMM-Newton data suggest the presence of a ``big blue bump'' in PKS 0558-504 extending from the optical band to ~ 3 keV. The soft X…
Abundances of planetary nebulae NGC 7662 and NGC 6741
Pottasch, S. R.; Beintema, D. A.; Feibelman, W. A. +1 more
The ISO and IUE spectra of the elliptical nebulae
Gas-phase SO 2 in absorption towards massive protostars
van Dishoeck, E. F.; Tielens, A. G. G. M.; Boonman, A. M. S. +1 more
We present the first detection of the nu3 ro-vibrational band of gas-phase SO2 in absorption in the mid-infrared spectral region around 7.3µm of a sample of deeply embedded massive protostars. Comparison with model spectra shows that the derived excitation temperatures correlate with previous C2H2 …
Mid and Far IR properties of late-type galaxies in the Coma and A1367 clusters: ISOCAM and ISOPHOT observations
Contursi, A.; Boselli, A.; Gavazzi, G. +3 more
We present Mid (MIR) and Far (FIR) Infrared observations of 18 spiral/irregular galaxies belonging to the Coma and A1367 clusters, carried out with the CAM and PHOT instruments on board the ISO satellite. Complementary photometry from the UV to the Near Infrared (NIR) together with Hα imaging, HI and 12CO line measurements allow us to s…
Variable Interstellar Absorption toward the Halo Star HD 219188: Implications for Small-Scale Interstellar Structure
Fitzpatrick, Edward L.; Welty, Daniel E.
Within the last 10 yr, strong, narrow Na I absorption has appeared at vsolar~-38 km s-1 toward the halo star HD 219188; that absorption has continued to strengthen, by a factor of 2-3, over the past 3 yr. The line of sight appears to be moving into/through a relatively cold, quiescent intermediate-velocity (IV) cloud, because…
The Large-Scale Ionized Outflow of CH Cygni
Livio, Mario; Corradi, Romano L. M.; Gonçalves, Denise R. +3 more
Hubble Space Telescope (HST) and ground-based [O II] and [N II] images obtained in the period 1996-1999 reveal a complex, ionized optical nebula around the symbiotic binary CH Cyg extending out to 18" or 5000 AU from the central stars. The observed velocity range of the nebula, derived from long-slit echelle spectra, is 130 km s-1. In s…
On the Nature of Prominence Absorption and Emission in Highly Ionized Iron and in Neutral Hydrogen
Engvold, Oddbjørn; Jakobsson, Hans; Tandberg-Hanssen, Einar +2 more
We have studied the behavior of the emission in the highly ionized EUV lines Fe ix/x, 171 Å, Fe xii, 195 Å, and Fe xv, 284 Å observed in quiescent prominences. Kucera, Andretta, and Poland (1998) have explained the absorption of other highly ionized metallic EUV lines as due to absorption in the hydrogen continuum. However, since the authors notic…
Caltech Faint Galaxy Redshift Survey. XV. Classifications of Galaxies with 0.2<Z<1.1 in the Hubble Deep Field North and its Flanking Fields
Cohen, Judith G.; van den Bergh, Sidney; Crabbe, Christopher
To circumvent the spatial effects of resolution on galaxy classification, the images of 233 objects of known redshift in the Hubble Deep Field (HDF) and its flanking fields that have redshifts in the range 0.20<z<1.10 were degraded to the resolution that they would have had if they were all located at a redshift of z=1.00. As in Paper XIV of…