molecular clouds Archives

A three-color image of the CygX region constructed from SPHEREx mosaics. In this image, blue is 1.13–1.19 μm, green is 2.9–3.20 μm (containing the H2O ice absorption feature), and red is 4.75–5.1 μm. Continuum emission from warm dust extends across the image, as evidenced by the extended orange clouds. Dark lanes are seen where the dust and H2O ice absorption are the strongest. Red sources appear in these dark lanes where there are background sources or embedded young stars shining through the dust. Blue stars are seen in regions with lower extinction or are foreground objects. -- The Astrophysical Journal

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar, Press Release

Astrochemistry Update: SPHEREx Maps Vast Galactic Ice Regions

by Keith CowingApril 15, 2026April 15, 2026

NASA’s SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer) mission has mapped interstellar ice at an unprecedented scale.

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar, Press Release

Methyl Isocyanate Formation from Oxygen Insertion in Methyl Cyanide Ices

by Keith CowingJuly 29, 2025July 29, 2025

In cold molecular clouds, UV photolysis of icy grain mantles generates radicals that lead to new molecule formation.

Regions surveyed to identify sources likely to present spectra with detectable ice features of H2O, CO, CO2, 13CO2, and other species in the 3 − 5 µm wavelength range where SPHEREx is sensitive. Upper panel: The regions are projected onto a background greyscale image representing the Rowles & Froebrich (2009) extinction map stretched from AV = 0 (white) to 2 mag (black). Solid red lines enclose the fields from which candidate SPHEREx targets have been drawn. Dotted blue lines indicate the boundaries of nearby molecular clouds as defined by Zucker et al. (2019). Red circles indicate the locations and sizes of ‘dark nebulae’ identified on the Palomar plates by Lynds (1962). Lower panel: same symbols as the upper panel, but the background greyscale image is the integrated 12CO(1-0) line intensity survey executed with the CfA 1.2 m telescope and its southern hemisphere counterpart (e.g., Dame et al. 2001; Heyer & Dame 2015). The inverted greyscale stretch ranges from −1 to 25 K km s−1, to indicate the extensive CO survey footprint. The white background indicates regions unobserved by the CfA CO survey except for the Magellanic Clouds (the SMC and LMC maps are described respectively in Rubio et al. (1991) and Cohen et al. (1988)). -- astro-ph.GA

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Imaging & Spectroscopy, Missions & Hardware, Status Report, Stellar Cartography

The SPHEREx Target List of Ice Sources (SPLICES)

by Keith CowingJanuary 31, 2025January 31, 2025

One of the primary objectives of the SPHEREx mission is to understand the origin of molecules such as H2O, CO2, and other volatile compounds at the early stages of planetary […]

CO brightness temperature maps for Cloud 378 at various vLSR. The black, cyan, and yellow polygons denote CO emission significance at 3σ, 6σ, and 9σ, respectively. The lines in the color bar indicate the CO emission at different levels. The red polygon highlights the dust contour boundary of the cloud as identified by Chen et al. (2020b). The method for calculating the dust contour threshold, Amin V , is described in Section 2.1. -- astro-ph.GA

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Interstellar, Status Report

The Correlation Between Dust and Gas Contents in Molecular Clouds

by Keith CowingSeptember 16, 2024September 16, 2024

Molecular clouds are regions of dense gas and dust in space where new stars and planets are born. There is a strong correlation between the distribution of dust and molecular […]

Column density maps of different species in the simulated galaxy after post-processing. The total hydrogen and H2 from the simulation are shown in the first two panels. The remaining panels show the column density of H2, C+ , C, and CO obtained via post-processing. The H2 from post-processing (top row, third panel) is remarkably similar to the H2 from the simulation (top row, second panel). CO dominates the carbon budget in the highest NH2 regions and is essentially absent when NH2 ≲ 1021 cm−2 . Atomic carbon traces the full extent of the H2 distribution while C + extends farther out to regions devoid of a significant amount of H2 -- astro-ph.GA

AI - Data - Apps - Cybernetics, Astrochemistry, Imaging & Spectroscopy, Interstellar, Status Report

HYACINTH: HYdrogen And Carbon chemistry In The INTerstellar Medium In Hydro Simulations

by Keith CowingFebruary 21, 2024February 20, 2024

Aims. We present a new sub-grid model, HYACINTH — HYdrogen And Carbon chemistry in the INTerstellar medium in Hydro simulations, for computing the non-equilibrium abundances of H2 and its carbon-based […]

Dependence of the formation of PO, PN and their ratio with the reaction rate coefficients ki of the 14 chemical reactions of the system. We plot the Pearson correlation r of the abundance of PO (blue bars), PN (red bars) and their ratio (green bars) with all 14 reaction rate coefficients for (a) T=10 K (b) T=100 K and (c) T=300 K, considering times t = 103 (light colors), t = 104 (vivid colors) and t = 105 yrs (dark colors). Correlations |r| > 0.05 are supported by p-values < 0.01. The correlations were calculated with sets consisting of all the combinations of 3 values of each of the 14 ki (bars), and also for a finer grid composed of 11 values of each of the 5 most influential ki (black diamonds). In all cases ki ranges from ki/10 to 10ki, being the values logarithmically distributed, and P-hydrogenation fraction fP = 0.5. -- astro-ph.SR

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar, Status Report

A Theoretical Approach To The Complex Chemical Evolution Of Phosphorus In The Interstellar Medium

by Keith CowingSeptember 18, 2023September 18, 2023

The study of phosphorus chemistry in the interstellar medium has become a topic of growing interest in astrobiology, because it is plausible that a wide range of P-bearing molecules were […]

Two individual lines of C6H5CN (left and middle panels) and the stacked spectrum of C6H5CN (right panels) for L1495B (top row), Lupus-1A (middle row), and L483 (bottom row), using the 130,13-120,12 line at 32833.813 MHz as a reference. The number of stacked lines and the significance level of the line stack signal (in units of σ) are indicated in the right panels. The systemic velocity of each source is indicated by a vertical dotted line. -- astro-ph.GA

Astrochemistry, Astronomy & Telescopes, Imaging & Spectroscopy, Status Report

How Widespread Are Aromatic Cycles In Cold Clouds?

by Keith CowingSeptember 8, 2023September 8, 2023

We report the detection of large hydrocarbon cycles toward several cold dense clouds. We observed four sources (L1495B, Lupus-1A, L483, and L1527) in the Q band (31-50 GHz) using the […]

The x and y axes are offsets in arcmin from the central map position; the z axis is velocity in km s−1. The emission starts at the 5σ level for both tracers. The bright star-forming cloud DR21 and other dense molecular clouds are embedded in a large-scale cloud structure only visible in [CII] (dark blue). An interactive version of these plots is found at https://astro.uni-koeln.de/stutzki/research/feedback/animations -- Nature Astronomy

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Imaging & Spectroscopy, Press Release

SOFIA Helps Complete Picture on Molecular Cloud Formation

by Keith CowingMay 3, 2023May 3, 2023

Molecular clouds — clumps of gas and dust in space, where molecules form — make up the densest regions of the Milky Way, but how they assemble is largely unknown.

Astrochemistry, Biochemistry & Organic Chemistry, Genomics, Proteomics, Bioinformatics, Interstellar, Status Report

A Sequential Acid-base (SAB) Mechanism In The Interstellar Medium: The Emergence Of Cis Formic Acid In Dark Molecular Clouds

by Keith CowingJanuary 19, 2023January 19, 2023

The abundance ratios between isomers of a COM observed in the ISM provides valuable information about the chemistry and physics of the gas and eventually, the history of molecular clouds.