We report the negative results from a search for 6.7 GHz methanol masers in the nearby spiral galaxy M33. We observed 14 GMCs in the central 4 kpc of the Galaxy, and found 3σ upper limits to the flux density of ∼9 mJy in spectral channels having a velocity width of 0.069 kms. By velocity shifting and combining the spectra from the positions observed, we obtain an effective 3σ upper limit on the...

We present the first fully sampled map of CO (1-0) emission from M82 covering the entire galaxy. Our map contains a ∼ 12 ×15 kpc area. We find that extraplanar CO emission, previously reported at short distances above the galactic plane, extends to heights of up to 6 kpc above the disk. Some of this emission is associated with tidal arms seen in HI, implying either that M82 contained substantia...

The rotationally resolved spectrum of the A1 u X 1 g 000–000 transition of C3, centered at 4051.6 Å, has been observed along 10 translucent lines of sight. To interpret these spectra, a new method for the determination of column densities and analysis of excitation profiles involving the simulation and fitting of observed spectra has been developed. The populations of lower rotational levels (J...

A new type of object called “Very Low Luminosity Objects (VeLLOs)” has been discovered by the Spitzer Space Telescope. VeLLOs might be substellar objects forming by accretion. However, some VeLLOs are associated with strong outflows, indicating the previous existence of massive accretion. The thermal history, which significantly affects the chemistry, between substellar objects with a continuou...

Abstract Molecules reside broadly in the interstellar space and can be detected via spectroscopic observations. To date, more than 271 molecular species have been identified medium or circumstellar envelopes. Molecular parameters measured laboratory make identification of new derivation physical possible. These are systematically collected into databases, two most commonly used being CDMS JPL d...

We present new models of the deuterium chemistry in protoplanetary disks, including, for the first time, multiply deuterated species. We use these models to explore whether observations in combination with models can give us clues as to which desorption processes occur in disks. We find, in common with other authors, that photodesorption can allow strongly bound molecules such as HDO to exist i...

The formation of water molecules from the reaction between ozone (O3) and D-atoms is studied experimentally for the first time. Ozone is deposited on nonporous amorphous solid water ice (H2O), and D-atoms are then sent onto the sample held at 10 K. HDO molecules are detected during the desorption of the whole substrate where isotope mixing takes place, indicating that water synthesis has occurr...

(Abridged) Life is distinctly homochiral. The origins of this homochirality are under active debate. Recently, propylene-oxide has been detected in the gas-phase interstellar medium (ISM) (McGuire et al. 2016). enantiomeric composition ISM may be probed through circular polarization measurements, but accurate estimates dichroism properties microwave transitions not available. We develop a model...

Recent experimental results about the formation of molecular hydrogen on astrophysically relevant surfaces under conditions close to those encountered in the interstellar medium are analyzed using rate equations. The parameters of the rate equation model are fitted to temperature-programmed desorption curves obtained in the laboratory. These parameters are the activation energy barriers for ato...

The first optical spectrum of an isolated polycyclic aromatic hydrocarbon large enough to survive the photophysical conditions of the interstellar medium is reported. Vibronic bands of the first electronic transition of the all benzenoid polycyclic aromatic hydrocarbon hexa-peri -hexabenzocoronene were observed in the 4080 − 4530 Å range by resonant 2-color 2-photon ionization spectroscopy. The...