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We have measured the deuterium fractionation (through the column density ratio N(N2D+)/N(N2H+)) and the CO depletion factor (ratio between expected and observed CO abundance) in a sample of 10 high-mass protostellar candidates, in order to…

Astrophysics · Physics 2009-11-11 F. Fontani , P. Caselli , A. Crapsi , R. Cesaroni , S. Molinari , L. Testi , J. Brand

CO$_2$ is an important, stable, and abundant molecule in the Universe, but it is very difficult to detect because it has no observable pure rotational transitions. The unique sensitivity and resolution of the James Webb Space Telescope…

Astrophysics of Galaxies · Physics 2026-02-25 J. Qiu , A. Ciurlo , M. R. Morris , P. Vermot , J. L. Bourlot , D. Rouan , A. Togi , T. Do , A. M. Ghez , E. Bron , F. L. Petit , Y. Clénet , E. A. C. Mills , J. R. Lu

The 12CO J=4-3 to J=13-12 lines of the interstellar medium from nearby galaxies, newly observable with the Herschel SPIRE Fourier Transform Spectrometer (FTS), offer an opportunity to study warmer, more luminous molecular gas than that…

Astrophysics of Galaxies · Physics 2015-06-23 J. Kamenetzky , N. Rangwala , J. Glenn , P. R. Maloney , A. Conley

High angular resolution H2CO line observations have been carried out for the low mass proto-binary star IRAS 16293-2422 using the OVRO millimeter array. Simultaneous continuum observations reveal that the source most probably contains two…

Astrophysics · Physics 2007-05-23 F. L. Schoeier , J. K. Jorgensen , E. F. van Dishoeck , G. A. Blake

H2O is the most abundant component of astrophysical ices. In most lines of sight it is not possible to fit both the H2O 3 um stretching, the 6 um bending and the 13 um libration band intensities with a single pure H2O spectrum. Recent…

Aims. We investigate the dominant formation mechanism of H2CO and CH3OH in the Horsehead PDR and its associated dense core. Methods. We performed deep integrations of several H2CO and CH3OH lines at two positions in the Horsehead, namely…

Astrophysics of Galaxies · Physics 2015-06-17 V. V. Guzman , J. R. Goicoechea , J. Pety , P. Gratier , M. Gerin , E. Roueff , F. Le Petit , J. Le Bourlot , A. Faure

Icy grain mantles are commonly observed through infrared spectroscopy toward dense clouds, cloud cores, protostellar envelopes and protoplanetary disks. Up to 80% of the available oxygen, carbon and nitrogen are found in such ices; the most…

We present observations of CO, 13CO and of H2O in the middle and far-infrared taken with the ISO-SWS and ISO-LWS spectrometers toward two positions in the Galactic Center region (Sgr A* and GCS-3). Both ice and gas phase molecules are…

Astrophysics · Physics 2009-10-31 Andrea Moneti , Jose Cernicharo , Juan Ramon Pardo

Context: It has been proposed that H$_2$ near-infrared lines may be excited by cosmic rays and allow for a determination of the cosmic-ray ionization rate in dense gas. One-dimensional models show that measuring both the H$_2$ gas column…

Astrophysics of Galaxies · Physics 2022-08-24 Brandt A. L. Gaches , Shmuel Bialy , Thomas G. Bisbas , Marco Padovani , Daniel Seifried , Stefanie Walch

Sensitive 5-38 um Spitzer Space Telescope (SST) and ground based 3-5 um spectra of the embedded low mass protostars B5 IRS1 and HH46 IRS show deep ice absorption bands superposed on steeply rising mid-infrared continua. The ices likely…

Formaldehyde is a key precursor in the formation routes of many complex organic molecules (COMs) in space. It is also an intermediate step in CO hydrogenation sequence that leads to methanol formation on the surface of interstellar grains…

Astrophysics of Galaxies · Physics 2025-02-04 A. F. Punanova , K. Borshcheva , G. S. Fedoseev , P. Caselli , D. S. Wiebe , A. I. Vasyunin

We present ISO-SWS observations of H2 pure-rotational line emission from the disks around low and intermediate mass pre-main-sequence stars as well as from young stars thought to be surrounded by debris disks. We detect `warm' (T ~ 100-200…

UV irradiation of simple ices is proposed to efficiently produce complex organic species during star- and planet-formation. Through a series of laboratory experiments, we investigate the effects of the H2O concentration, the dominant ice…

Astrophysics of Galaxies · Physics 2015-05-19 Karin I. Oberg , Ewine F. van Dishoeck , Harold Linnartz , Stefan Andersson

Analyses of infrared signatures of CO$_2$ in water dominated ices in the ISM can give information on the physical state of CO$_2$ in icy grains and on the thermal history of the ices themselves. In many sources, CO$_2$ was found in the…

Instrumentation and Methods for Astrophysics · Physics 2018-12-19 Jiao He , SM Emtiaz , Adwin Boogert , Gianfranco Vidali

We report the detection of D2CO in a sample of starless dense cores, in which we previously measured the degree of CO depletion. The deuterium fractionation is found extremely high, [D2CO]/[H2CO] ~ 1-10 %, similar to that reported in…

Cosmic rays regulate the dynamics and the chemical processes in the densest and coldest regions of the ISM. Still, the determination of the cosmic-ray ionisation rate of H$_2$ (${\zeta^{\rm ion}_{{\rm H}_2}}$) is plagued by uncertainties in…

Astrophysics of Galaxies · Physics 2024-07-03 A. Socci , G. Sabatini , M. Padovani , S. Bovino , A. Hacar

Spectral lines from formaldehyde (H2CO) molecules at cm wavelengths are typically detected in absorption and trace a broad range of environments, from diffuse gas to giant molecular clouds. In contrast, thermal emission of formaldehyde…

Astrophysics of Galaxies · Physics 2021-04-02 Onic I. Shuvo , E. D. Araya , W. S. Tan , P. Hofner , S. Kurtz , Y. M. Pihlstrom , I. M. Hoffman

CO2 ice is one of the most abundant components in ice-coated interstellar ices besides H2O and CO, but the most favorable path to CO2 ice is still unclear. Molecular dynamics calculations on the ultraviolet photodissociation of different…

Chemical Physics · Physics 2015-06-17 Carina Arasa , Marc C. van Hemert , Ewine F. van Dishoeck , Geert-Jan Kroes

Gaseous H2O has been detected in several cold astrophysical environments, where the observed abundances cannot be explained by thermal desorption of H2O ice or by H2O gas phase formation. These observations hence suggest an efficient…

Astrophysics · Physics 2011-02-11 Karin I. Oberg , Harold Linnartz , Ruud Visser , Ewine F. van Dishoeck

The detection of high gas-phase abundances of SO2 and SO in the cold envelope of an intermediate mass protostar suggests that these molecules might form on icy dust grains and subsequently desorb to the gas phase by non-thermal desorption…

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