The molecular and solid-state models of the UIB widths are confronted with observations from ground-based telescopes and the ISO satellite. The PAH (Polycyclic Aromatic Hydrocarbons) model requires that free-flying molecules be excited by vacuum UV radiation. However, recent laboratory measurements of vibrational emission reveal that, in this case, band widths are several times larger than obse...

Aims. Supernovae offer the unique possibility to probe diffuse extra-galactic sightlines via observation of the optical transitions of atoms, molecules and the diffuse interstellar bands (DIBs). Through optical spectroscopy the presence of (complex) molecules in distant galaxies can be established and used to derive local physical conditions of the interstellar medium (ISM). Methods. High resol...

Outflows from young stellar objects have been identified as a possible source of turbulence in molecular clouds. To investigate the relationship between outflows, cloud dynamics and turbulence, we compare the kinematics of the molecular gas associated with NGC 1333, traced in CO(1-0), with the distribution of young stellar objects (YSOs) within. We find a velocity dispersion of ∼ 1− 1.6km/s in ...

We present initial results from the first optical spectroscopic survey of high latitude Galactic cirrus clouds. The observed shape of the cirrus spectrum does not agree with that of scattered ambient Galactic starlight. This mismatch can be explained by the presence of Extended Red Emission (ERE) in the diffuse interstellar medium, as found in many other astronomical objects, probably caused by...

We found high molecular fractions ( fmol; ratio of the molecular to total gas surface densities) in three of five Virgo spiral galaxies in spite of their low total gas column density, based on 12CO(J = 1−0) observations with the Nobeyama 45 m telescope equipped with a multi-beam receiver, BEARS. We interpret this as a result of environmental effects. Combining the CO data with HI data, the rela...

Context. Many C-, O-, and H-containing complex organic molecules (COMs) have been observed in the interstellar medium (ISM) their formation has investigated laboratory experiments. An increasing number of recent detections large N-bearing COMs motivates our experimental investigation chemical origin. Aims. We investigate potential role acetonitrile (CH 3 CN) as a parent molecule to COMs, motiva...

We mapped a 13×22 pc region in emission from 492 GHz [C I] and, for the first time, 551 GHz 13CO(5→4) in the giant molecular cloud M17SW. The morphologies of the [C I] and 13CO emission are strikingly similar. The extent and intensity of the [C I] and 13CO(5→4) emission is explained as arising from photodissociation regions on the surfaces of embedded molecular clumps. Modeling of the 13CO(5→4)...

We report Mopra (ATNF), Anglo-Australian Telescope, and Atacama Submillimeter Telescope Experiment observations of a molecular core in Carina, BY72 = G286.21+0.17, which give evidence of large-scale gravitational infall in the dense gas. From the millimetre and far-infrared data, the core has mass ∼ 5,000 M⊙, luminosity ∼ 2–3×10 L⊙, diameter ∼ 0.9 pc, and mass infall rate ∼ 2.4×10 −2 M⊙yr . If ...

The HH1/2 system has been observed with the two spectrometers on board the Infrared Space Observatory. Diffuse [Cii]158μm emission indicate the presence of a Photo-Dissociation Region (PDR) which is only in part due to the external Far-UV irradiation from the nearby Orion Nebula. Additional irradiation must be originated locally and we show that the FUV field produced in the recombination regio...

We report the detection of fully resolved absorption lines of A–X bands from interstellar CO and CO, through high-resolution spectroscopy of X Persei with the Space Telescope Imaging Spectrograph. The first ultraviolet measurement of an interstellar CO column density shows that its isotopomeric ratio is CO/CO p . Simultaneously, the second ultraviolet detection of interstellar CO establishes it...