Search Publications
Modeling gas-phase H2O between 5 µ m and 540 µ m toward massive protostars
van Dishoeck, E. F.; Bergin, E. A.; Melnick, G. J. +4 more
We present models and observations of gas-phase H2O lines between 5 and 540 mu m toward deeply embedded massive protostars, involving both pure rotational and ro-vibrational transitions. The data have been obtained for 6 sources with both the Short and Long Wavelength Spectrometers (SWS and LWS) on board the Infrared Space Observatory (…
The circumstellar envelope of the C-rich post-AGB star HD 56126
Waters, L. B. F. M.; Hony, S.; de Koter, A. +1 more
We present a detailed study of the circumstellar envelope of the post-asymptotic giant branch ``21 mu m object'' HD 56126. We build a detailed dust radiative transfer model of the circumstellar envelope in order to derive the dust composition and mass, and the mass-loss history of the star. To model the emission of the dust we use amorphous carbon…
Revisiting the solid HDO/H2O abundances
Dartois, E.; Geballe, T. R.; d'Hendecourt, L. +3 more
We revisit the reported detection and upper limits on HDO in ice mantles present in the molecular cloud environments of the massive young protostars Gl 2136 and W33 A, using independent VLT-ISAAC and UKIRT-CGS4 spectroscopic observations. We also present VLT and UKIRT spectra of RAFGL 7009 near the HDO absorption wavelength and reanalyze the ISO-S…
An XMM-Newton observation of IGR J16320-4751 = AX J1631.9-4752
Tomsick, J. A.; Rodriguez, J.; Walter, R. +4 more
The hard X-ray sensitivity and arcminute position accuracy of the recently launched International Gamma-Ray Laboratory (INTEGRAL) has lead to the (re-)discovery of a class of heavily absorbed hard X-ray sources lying in the Galactic plane. We report on the analysis of an XMM observation of such a source IGR J16320-4751 = AX J1631.9-4752. Our analy…
ISOCAM and molecular observations of the edge of the Horsehead nebula
Perault, M.; Olofsson, G.; Boulanger, F. +20 more
We present ISOCAM observations (5-18 mu m) of the Horsehead nebula, together with observations of the (J=1-0) and (J=2-1) transitions of 12CO, 13CO and C18O taken at the IRAM 30-m telescope. The Horsehead nebula presents a typical photodissociation region illuminated by the O9.5 V system sigma Ori. The ISOCAM emiss…
Spectroscopic and photometric studies of low-metallicity star-forming dwarf galaxies. III. SBS 1415+437
Thuan, T. X.; Izotov, Y. I.; Green, R. F. +4 more
We present a detailed optical spectroscopic and B, V, I, Hα photometric study of the metal-deficient cometary blue compact dwarf (BCD) galaxy SBS 1415+437. We derive an oxygen abundance 12 + log (O/H) = 7.61+/-0.01 and 7.62+/-0.03 (Z = Zsun/20) in the two brightest H II regions, among the lowest in BCDs. The helium mass fractions in the…
A wavelet packets equalization technique to reveal the multiple spatial-scale nature of coronal structures
Stenborg, G.; Cobelli, P. J.
Precise determination of onset times of dynamical events as observed by coronagraphs requires a high-degree-of-accuracy tracking of the structures involved. In particular, early steps in the evolution turn to be of utmost importance. However, corresponding features often lack the sharpness needed to obtain unambiguous results. To overcome this con…
A radio continuum and infrared study of Galactic H II regions
Tielens, A. G. G. M.; van der Hulst, J. M.; Martín-Hernández, N. L.
We present observations of the 4.8 and 8.6 GHz continuum emission towards 11 southern H Ii regions made with the Australian Telescope Compact Array. The observed objects were selected from the Infrared Space Observatory (ISO) spectral catalogue of compact H Ii regions \citep{peeters:catalogue}. The morphologies observed for practically all the sou…
The INTEGRAL spacecraft - in-orbit performance
Winkler, C.; Clausen, K.; Much, R. +4 more
The INTEGRAL satellite was successfully launched from Baikonur on 17 October, 2002. INTEGRAL is an observatory for gamma-ray astronomy. The goals are to provide unprecedented high resolution imaging capability for unambiguous identification of gamma ray sources and high energy resolution for line spectroscopy. This paper summarises the actual orbi…
The physical structure of high-mass star-forming cores
van der Tak, F. F. S.; Hatchell, J.
We present models of the temperature and density structure of the envelopes of ten deeply embedded massive stars associated with ultracompact HII regions. Constraints come from 60-1300 mum photometry including ISO-LWS spectra, maps at 450 and 850 mum , and CS emission line data. Radial profiles extracted from the maps after removing neighbouring s…