K. Mattila

Low upper limits on the O2 abundance from the Odin satellite

For the first time, a search has been conducted in our Galaxy for the 119 GHz transition connecting to the ground state of O2, using the Odin satellite. Equipped with a sensitive 3 mm receiver (Tsy ...

The Small Magellanic Cloud in the far infrared. II. Global properties

We present global IR properties of the Small Magellanic Cloud using an ISOPHOT 170 µm map and re-visited IRAS data. The integrated 170 µm flux is 14 950 ± 2300 Jy, and the integrated IR flux is F1−1000 = 7.48 × 10 −10 Wm −2 . Discrete sources contribute 28%, 29%, and 36% to the integrated flux at 60 µm, 100 µm, and 170 µm, respectively. Most of the total emission arises from diffuse emission regions surrounding the HII regions. The SED can be modelled by the composition of a 45 K, a 20.5 K and a 10 K blackbody component with emissivity index n = 2. A color temperature map is constructed from the ISOPHOT 170 µm and the IRAS 100 µm HiRes maps. The average dust temperature is TD = 20.3 K. The total dust mass is found to be MD = 7.8 × 10 5 M� , yielding a gas-to-dust mass ratio Mgas/Mdust ≈ 540, a value 25 times lower than found by former studies. The global star formation rate is estimated to SFRtotal ≈ 0.05 Myr −1 . The comparison with other irregular

Far-infrared and molecular line observations of Lynds 183 – Studies of cold gas and dust

We have mapped the dark cloud L183 in the far-infrared at 100 m and 200 m with the ISOPHOT photometer aboard the ISO satellite. The observations make it possible for the rst time to study the distribution and properties of the large dust grains in L183 without confusion from smaller grains. The observations show clear colour temperature variations which are likely to be caused by changes in the emission properties of the dust particles. In the cloud core the far-infrared colour temperature drops below 12 K. The data allow a new determination of the cloud mass and the mass distribution based on dust emission. The estimated mass within ar adius of 10 0 from the cloud centre is 25M. We have mapped the cloud in several molecular lines including DCO+(2{1) and H 13 CO+(1{0). These species are believed to be tracers of cold and dense molecular material and we detect a strong anticorrelation between the DCO+ emission and the dust colour temperatures. In particular, the DCO+(2{1) emission is not detected towards the maximum of the 100 m emission where the colour temperature rises above 15 K. The H 13 CO+ emission follows closely the DCO+ distribution but CO isotopes show strong emission even towards the 100m peak. Detailed comparison of the DCO+ and C 18 O maps shows sharp variations in the relative intensities of the species. Morphologically the 200 m dust emission traces the distribution of dense molecular material as seen e.g. in C 18 O lines. A comparison with dust column density shows, however, that C 18 O is depleted by a factor of1.5 in the cloud core. We present results of R -a ndB-band starcounts. The extinction is much better correlated with the 200 mt han with the 100m emission. Based on the 200m correlation at low extinction values we deduce a value of 17 m for the visual extinction towards the cloud centre where no background stars are observed anymore.

Unidentified infrared bands in the interstellar medium across the Galaxy

We present a set of 6–12

Discovery and imaging of a Galactic cirrus cloud with the far ultraviolet space telescope

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First detection of NH3 (10 -g 00) from a low mass cloud core. On the low ammonia abundance of the rho Oph A core

ISOPHOT-S spectra of the general interstellar medium of the Milky Way. This part of the spectrum is dominated by a series of strong, wide emission features commonly called the Unidentified Infrared Bands. The sampled area covers the inner Milky Way from l = -60°to +60° with a ten-degree step in longitude and nominal latitudes b = 0°, ± 1°. For each grid position the actual observed direction was selected from IRAS 100

Detection of 6 K gas in Ophiuchus D

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A far infrared view of low mass star formation in the Cederblad 110 nebula of Chamaeleon I

maps to minimize contamination by point sources and molecular clouds. All spectra were found to display the same spectral features. Band ratios are independent of band strength and Galactic coordinates. A comparison of total observed flux in band features and IRAS 100

A Corona Australis cloud filament seen in NIR scattered light - I. Comparison with extinction of background stars

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ISO far-infrared observations of the high-latitude cloud L1642 - II. Correlated variations of far-infrared emissivity and temperature of “classical large” dust particles

emission, a tracer for large interstellar dust grains, shows high correlation at large as well as small (1´) scales. This implies a strong connection between large dust grains and the elusive band carriers; the evolutionary history and heating energy source of these populations must be strongly linked. The average mid-infrared spectrum of the Milky Way is found to be GROUP the average spectrum of spiral galaxy NGC 891 GROUP The common spectrum can therefore be used as a template for the 6–12