astro-ph.GA Archives

The continuum-subtracted KCWI spectrum of 3I/ATLAS between 3325 Å and 5225 Å, extracted from a 2'' aperture centered on the comet. Cometary emission species are denoted as follows: Ni as red dotted lines, Fe as green dashed lines, CN as solid blue lines, C2 as dotted light purple lines, and C3 as dashed dark purple lines. The C2 and C3 lines shown may not be individually resolved. -- astro-ph.EP

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Interstellar, Status Report

Post-Perihelion Integral Field Spectroscopy Of The Interstellar Comet 3I/ATLAS

by Keith CowingJanuary 27, 2026January 27, 2026

The environs of other stellar systems may be directly probed by analyzing the cometary activity of interstellar objects. The recently discovered interstellar object 3I/ATLAS was the subject of an intensive […]

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

CO Diffusion on Interstellar Amorphous Solid Water: A Computational Study

by Keith CowingJanuary 23, 2026January 23, 2026

Surface chemistry on interstellar dust grains is recognized as a central component in astrochemical models, representing a plausible formation route for many of the observed complex molecular species.

A notional Dyson sphere - Grok via Astrobiology.com

Astronomy & Telescopes, Biosignatures & Paleobiology, Imaging & Spectroscopy, Intelligence & Language, Interstellar, SETI & Technosignatures, Status Report

WISE/CatWISE Constraints On Dysonian Waste-Heat Technosignatures In Nearby Galaxies

by Keith CowingJanuary 17, 2026

We search for galaxy-scale (Dysonian) waste heat in the mid-infrared using WISE. Starting from the 2MASS Redshift Survey (2MRS), we cross-match to CatWISE2020 and AllWISE, apply standard MIR AGN/starburst vetoes […]

Relative energies (including zero-point energy, ZPE, corrections)

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

Expanding the C3H6O2 Isomeric Interstellar Inventory: Discovery of Lactaldehyde and Methoxyacetaldehyde in G+0.693-0.027

by Keith CowingJanuary 17, 2026January 17, 2026

The tentative detection of 3-hydroxypropanal (HO(CH2)2C(O)H) toward the Galactic center molecular cloud G+0.693-0.027 prompts a systematic survey in this source aimed at detecting all C3H6O2 isomers with available spectroscopy. We […]

The initial condition of the converging flow simulation. The color shows the number density of hydrogen nuclei on the 𝑧 = 0 plane. -- astro-ph.GA

Astrochemistry, Imaging & Spectroscopy, Intelligence & Language, Status Report

Time-dependent Chemical Evolution During Cloud Formation: H2-regulated Chemistry In Diffuse Molecular Cloud

by Keith CowingJanuary 13, 2026January 13, 2026

We investigate the chemical evolution of a forming molecular cloud behind an interstellar shock wave. We conduct three-dimensional magnetohydrodynamics simulations of the converging flow of atomic gas, including a simple […]

The abundance ratios, log(X/O), versus metallicity for nitrogen (top-left), neon (top-right), sulphur (bottom-left) and argon (bottom-right). The blue lines shows literature relations derived by Izotov et al. (2006), Andrews & Martini (2013), Nicholls et al. (2017) and Berg et al. (2012, 2019). The orange lines show the predicted relations from chemical evolution models for the Solar neighbourhood, Milky Way halo and bulge stars by Kobayashi et al. (2020). The cyan ⊙-sign shows the solar abundance ratio (Asplund et al. 2021). The pink datapoints in the top-left panel show a selection of galaxies with low metallicity and high N/O ratios as discussed in the text. All data points are coloured by the Gaussian kernel density of the plotted distribution. Typical uncertainties are shown by the black error bars in the top-left corner of each panel. -- astro-ph.GA

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

Electron Temperature Relations And The Direct N, O, Ne, S And Ar abundances Of 49959 Star-forming Galaxies In DESI Data Release 2

by Keith CowingJanuary 13, 2026January 13, 2026

We present the largest direct-method abundance catalogue of galaxies to date, containing measurements of 49959 star-forming galaxies at z<0.96 from DESI Data Release 2. By directly measuring electron temperatures across […]

Distribution of the targets observed in this work across the Milky Way in white “+” symbols along with their identifiers, as listed in Table 1. The red asterisk and Sun symbols mark the Galactic centre at (0, 0) kpc and the position of the Solar System at (0, −8.15) kpc, respectively (Reid et al. 2019). The sources are projected onto the Galactic plane with parallax-based distances from Reid et al. (2019). The underlying Milky Way spiral arm pattern follows the log-periodic model from the same study, with colours adapted from Jacob et al. (2022). The background image, is an artist’s impression of the large-scale structure of the Milky Way, courtesy of ESA/Gaia/DPAC/Stefan Payne-Wardenaar. -- astro-ph.GA

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

APEX Survey Of Interstellar HCl: 35Cl/37Cl Isotopic Ratios In Dense Cores And Outflows

by Keith CowingDecember 28, 2025December 28, 2025

Despite being only the 19th most abundant element in the interstellar medium, chlorine’s reactivity and volatility give rise to a unique interstellar chemistry, favouring the formation of several chlorine-bearing hydrides.

The different views of B3LYP-D3(BJ)/6- 311++G(d,p) level optimized geometric structures for 9- iminofluorene (left) and benzophenone imine (right). The arrow shows C9 position of iminofluorene. -- astro-ph.GA

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

Rotational Spectra And Search For Aromatic Imines: 9-Iminofluorene And Benzophenone Imine

by Keith CowingDecember 26, 2025December 26, 2025

Interstellar detections of several cyano derivatives of large polycyclic aromatic hydrocarbons (PAHs) have now been achieved, enabled by accurate laboratory measurements of their microwave rotational spectra.

Structures and relative energy levels of cis-HNSO (left, as the ground state), trans-HNSO (right, at 3.7 kcal/mol), and the transition state (middle, at 14.5 kcal/mol); energy values were derived by Kumar and Francisco (2017). Red atom corresponds to oxygen, yellow to sulfur, blue to nitrogen, and grey to hydrogen. -- astro-ph.GA

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

Laboratory Detection and Rotational Spectroscopy of trans-HNSO: Implications for Astronomical Observations

by Keith CowingDecember 26, 2025December 26, 2025

Sulfur-bearing molecules are central to interstellar chemistry, yet their observed abundances in the gas phase remain far below cosmic expectations in dense interstellar regions. Mixed N-S-O species such as thionylimide […]

Schematic summary of COM-poor hot cores in low-metallicity environments. In the LMC, COM-poor hot cores are currently found only outside the bar region (i.e., lower metallicity, Z), where all of them have high bolometric luminosity (Lbol) and are associated with high star-formation (SF) activity (S24µm,10pc indicates 24 µm surface brightness averaged over a 10 pc radius around each hot core). In the even lower-metallicity SMC, both known hot cores are COM-poor despite having only moderate luminosity and star-formation activity. In contrast, the two known hot cores in the outer Galaxy are COM-rich despite the low metallicity, highlighting that low metallicity alone does not necessarily result in COM-poor chemistry. -- astro-ph.GA

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

MAGellanic Outflow And Chemistry Survey (MAGOS): Hot Cores In The LMC

by Keith CowingDecember 25, 2025December 25, 2025

The Large Magellanic Cloud (LMC) provides a key laboratory for exploring the diversity of star formation and interstellar chemistry under subsolar metallicity conditions.

astro-ph.GA

Post-Perihelion Integral Field Spectroscopy Of The Interstellar Comet 3I/ATLAS

CO Diffusion on Interstellar Amorphous Solid Water: A Computational Study

WISE/CatWISE Constraints On Dysonian Waste-Heat Technosignatures In Nearby Galaxies

Expanding the C3H6O2 Isomeric Interstellar Inventory: Discovery of Lactaldehyde and Methoxyacetaldehyde in G+0.693-0.027

Time-dependent Chemical Evolution During Cloud Formation: H2-regulated Chemistry In Diffuse Molecular Cloud

Electron Temperature Relations And The Direct N, O, Ne, S And Ar abundances Of 49959 Star-forming Galaxies In DESI Data Release 2

APEX Survey Of Interstellar HCl: 35Cl/37Cl Isotopic Ratios In Dense Cores And Outflows

Rotational Spectra And Search For Aromatic Imines: 9-Iminofluorene And Benzophenone Imine

Laboratory Detection and Rotational Spectroscopy of trans-HNSO: Implications for Astronomical Observations

MAGellanic Outflow And Chemistry Survey (MAGOS): Hot Cores In The LMC

Tricorder Tech: New Handheld Device Maps Chemical Composition Using Infrared Light

No Statistically Significant Evidence For A Correlation Between Stellar And planetary Composition

Water Planet Recon: How Accurately Can We Measure Earth Ocean’s Deepest Point?

Webb Reveals A Stunning Panorama Of Star Formation

Deep Learning of SHERLOC Raman Spectra For Facilitating Mars Astromaterial Identification