Search Publications
Spectroscopy of polycyclic aromatic hydrocarbons and very small grains in photodissociation regions
Joblin, C.; Rapacioli, M.; Boissel, P.
We have coupled a singular value decomposition method with a Monte Carlo search algorithm to analyse the mid-infrared ISOCAM spectral maps of photodissociation regions (PDRs) in NGC 7023 and ρ Oph-SR3.Three different spectra and their associated spatial distribution were extracted from this analysis. It is shown that they can be associated with po…
ISM properties in low-metallicity environments. III. The spectral energy distributions of II Zw 40, He 2-10 and NGC 1140
Bernard, J. -P.; Madden, S. C.; Galliano, F. +2 more
We present new 450 and 850 µm SCUBA data and 1.3 mm MAMBO data of the dwarf galaxies II Zw 40, He 2-10 and NGC 1140. Additional ISOCAM, IRAS as well as ground based data are used to construct the observed mid-infrared to millimeter spectral energy distribution of these galaxies. These spectral energy distributions are modeled in a self-consi…
Discovery of 10 µm silicate emission in quasars. Evidence of the AGN unification scheme
Siebenmorgen, R.; Schulz, B.; Haas, M. +1 more
According to the unified scheme, AGN are surrounded by a dust-torus, and the observed diversity of AGN properties results from the different orientations relative to our line of sight. The strong resonance of silicate dust at 10 µm is therefore, as expected, seen in absorption towards many type-2 AGN. In type-1 AGN, it should be seen in emis…
Dust-enshrouded giants in clusters in the Magellanic Clouds
van Loon, J. Th.; Zijlstra, A. A.; Marshall, J. R.
We present the results of an investigation of post-Main Sequence mass loss from stars in clusters in the Magellanic Clouds, based around an imaging survey in the L'-band (3.8 µm) performed with the VLT at ESO. The data are complemented with JHKs (ESO and 2MASS) and mid-IR photometry (TIMMI2 at ESO, ISOCAM on-board ISO, and data fr…
Spitzer IRS spectroscopy of 3CR radio galaxies and quasars: testing the unified schemes
Siebenmorgen, R.; Schulz, B.; Haas, M. +2 more
With the Spitzer Space Telescope Infrared Spectrograph (IRS) we have observed seven powerful FR 2 radio galaxies and seven quasars. Both samples, the galaxies and the quasars, are comparable in isotropic 178 MHz luminosity (10^26.5 W/Hz ⪉ P_178 MHz ⪉10^29.5 W/Hz) and in redshift range (0.05 ⪉ z ⪉ 1.5). We find for both samples similar distribution…
Integrated spectrum of the planetary nebula NGC 7027
Barlow, M. J.; Zhang, Y.; Liu, X. -W. +2 more
We present deep optical spectra of the archetypal young planetary nebula (PN)
A 3-5 µm VLT spectroscopic survey of embedded young low mass stars II. Solid OCN-
van Dishoeck, E. F.; Pontoppidan, K. M.; Fraser, H. J. +1 more
The 4.62 µm (2164.5 cm-1) “XCN” band has been detected in the M-band spectra of 34 deeply embedded young stellar objects (YSO's), observed with high signal-to-noise and high spectral resolution with the VLT-ISAAC spectrometer, providing the first opportunity to study the solid OCN- abundance toward a large number of low…
Warm gas in the cold diffuse interstellar medium: Spectral signatures in the H2 pure rotational lines
Falgarone, E.; Hily-Blant, P.; Pineau Des Forêts, G. +1 more
We present ISO-SWS observations of five pure rotational lines of H2 along a line of sight through the Galaxy which avoids regions of massive star formation. It samples 30 mag of gas, half of it (i.e. 15 mag) being diffuse gas running from the solar neighbourhood to the molecular ring, up to the far side of the Galaxy. The intensities of…
Oxygen-rich AGB stars with optically thin dust envelopes
Heras, A. M.; Hony, S.
The dust composition and dynamics of the circumstellar envelopes of oxygen-rich AGB stars with low mass-loss rates (5 × 10-8-10-5 M⊙ yr-1) have been investigated. We have analyzed the ISO-SWS spectra of twenty-eight oxygen-rich AGB stars with optically thin shells, and modelled the observations with the …
Weak-line T Tauri stars: circumstellar disks and companions. I. Spectral energy distributions and infrared excesses
Ray, T. P.; Gras-Velázquez, À.
We have analysed new infrared photometric data taken by the Infrared Space Observatory, in combination with 2MASS data where available, of 12 weak-line T Tauri stars (WTTS), belonging to different molecular clouds. A control study of 6 classical T Tauri stars (CTTS) for comparison with IRAS data has also been made. WTTS traditionally are not expec…