相关论文: Molecular absorption lines toward star-forming reg…
New HCN, HNC, and HCO+ measurements of 46 normal galaxies in transitions up to J=4-3 are included in a multitransition database covering HCN and HCO+ (130 galaxies) and HNC (94 galaxies). The near-linear luminosity relations are dominated…
Context. Radio frequency molecular absorption lines appear along sight lines with AV well below 1 mag, revealing the presence of H2 in diffuse gas even when 2.6mm CO emission is absent. Aims. We discuss absorption lines of HCO+, C2H, HCN,…
The star forming processes strongly influence the ISM chemistry. Nowadays, there are available many high-quality databases at millimeter wavelengths. Using them, it is possible to carry out studies that review and deepen previous results.…
As a complement to the HyGAL Stratospheric Observatory for Infrared Astronomy Legacy Program, we report the results of a ground-based absorption line survey of simple molecules in diffuse and translucent Galactic clouds. Using the Institut…
We have complemented existing observations of HI absorption with new observations of HCO$^+$, C$_2$H, HCN, and HNC absorption from the Atacama Large Millimeter/submillimeter Array (ALMA) and the Northern Extended Millimeter Array (NOEMA) in…
While the best tracer of the molecular component and its dynamics in galaxies is the CO molecule, which excitation is revealed by its isotopic and (2-1)/(1-0) ratios, the denser gas is revealed by molecules such as HCN, HNC, HCO+ or CN,…
We used the ARO 12m antenna to observe emission from the J=1-0 lines of carbon monoxide, \hcop\ and HNC and the J=2-1 line of CS toward and around the continuum peak used for absorption studies and we compare them with CH, HNC, C\p\ and…
We aim to better understand the emission of molecular tracers of the diffuse and dense gas in giant molecular clouds and the influence that metallicity, optical extinction, density, far-UV field, and star formation rate have on these…
The aim of this study is to investigate systematic chemical differentiation of molecules in regions of high mass star formation. We observed five prominent sites of high mass star formation in HCN, HNC, HCO+, their isotopes, C18O, C34S and…
Based on measurements with the Effelsberg 100-m telescope, a multi-line study of molecular species is presented toward the south-western source of the gravitational lens system PKS 1830-211, which is by far the best known target to study…
We present high-resolution observations of interstellar CN, CH, CH^{+}, \ion{Ca}{1}, and \ion{Ca}{2} absorption lines toward the multiple star systems HD206267 and HD217035. Substantial variations in CN absorption are observed among three…
ALMA data toward QSO J1851+0035 ($l$=$33.498^{\circ}$, $b$=$+0.194^{\circ}$) were used to study absorption lines by Galactic molecular gas. We detected 17 species (CO, $^{13}$CO, C$^{18}$O, HCO$^+$, H$^{13}$CO$^+$, HCO, H$_2$CO, C$_2$H,…
We have observed rovibrational transitions of acetylene and HCN near 13 microns in absorption toward GL2591. We also observed rotational lines of CS, HCN, H2CO, and HCO+. The combined data are analyzed in terms of models with a cloud…
The transition between atomic and molecular hydrogen is associated with important changes in the structure of interstellar clouds, and marks the beginning of interstellar chemistry. Because of the relatively simple networks controlling…
We report single-dish multi-transition measurements of the 12^CO, HCN, and HCO^+ molecular line emission as well as HNC J=1-0 and HNCO in the two ultraluminous infra-red galaxies Arp220 and NGC6240. Using this new molecular line inventory,…
We present 3 mm observations obtained with the IRAM 30-m telescope for ten nearby gas-rich active galaxies spanning three orders of magnitude in infrared luminosity. Emission lines of HCO+(1-0), HCN(1-0), and C2H(1-0) were simultaneously…
Trends observed in galaxies, such as the Gao \& Solomon relation, suggest a linear relation between the star formation rate and the mass of dense gas available for star formation. Validation of such relations requires the establishment of…
We present very high signal-to-noise ratio absorption-line observations of CN and CH+ along 13 lines of sight through diffuse molecular clouds. The data are examined to extract precise isotopologic ratios of 12CN/13CN and 12CH+/13CH+ in…
We report the detection of molecular absorption lines at z=0.7645 towards the radio-loud QSO PMN 0134-0931. The CO J=2-1 and HCO+ J=2-1 lines are seen in absorption along two different lines of sight to lensed images of the background QSO.…
Stars form out of the densest parts of molecular clouds. Far-IR emission can be used to estimate the Star Formation Rate (SFR) and high dipole moment molecules, typically HCN, trace the dense gas. A strong correlation exists between HCN and…