![Overview of the ML-DH framework. Top: Training stage, using DFT energies, forces, and dipoles to train the NNFF and EPNN. Bottom: Prediction stage, yielding IR spectra via NNFF optimization, normal mode analysis, and EPNN dipole derivatives.-- [astro-ph.GA]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/A-machine.png?resize=1200%2C719&ssl=1)
[astro-ph.GA] The interpretation of interstellar aromatic infrared bands (AIBs) relies on reference spectral libraries, but the chemical space covered by existing databases remains incomplete relative to the vast structural diversity […]
Polycyclic Aromatic Hydrocarbons
Posted inAstrochemistry
Infrared Spectroscopy Of Cyanonaphthalenes Under Interstellar Relevant Conditions And Their Potential Connection With Astronomical Aromatic Infrared Bands
[Astronomy & Astrophysics] Context. Aromatic infrared bands (AIBs) are widely observed in diverse astrophysical environments and are generally attributed to vibrational emission from polycyclic aromatic hydrocarbons (PAHs). The recent interstellar […]
![The per-tile processing chain, applied to the Detector-4 tile of Fig. 1. (a) After flag masking and zodiacal-light subtraction, the input to the stellar subtraction. (b) After fitting and subtracting the empirical PSF at every catalogued source above the magnitude limit, with the saturated cores of the brightest stars masked. (c) After the median filter and the Gaussian smoothing to 2.6 ′ , which is what is coadded into the HEALPix maps. All three panels share a single histogram-equalised colour scale. -- [astro-ph.GA]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/A-Full-Sky.png?resize=1200%2C637&ssl=1)
Posted inAstrochemistry
A Full-Sky SPHEREx Map of Integrated 3.3 And 3.4 μm PAH Emission
[astro-ph.GA] Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the interstellar medium and are among its smallest carbonaceous grains.
![Ratio maps involving the PAH7.7 feature and the F1500W synthetic photometry applied to the MRS cubes for ASPECS galaxies. The first row of panels shows the maps of the total PAH7.7 feature to the synthetic F1500W photometry. Ratios above 1 are possible because the wings of the PAH feature extend well beyond the filter (see text for details and Donnan et al. 2026b). The second row of panels is the fraction of PAH7.7 feature within the F1500W filter to the synthetic F1500W photometry. The third row of panels is the same as the second but for the fraction of continuum emission within the F1500W to the synthetic F1500W photometry -- [astro-ph.GA]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/PAHSPECS.png?resize=1200%2C718&ssl=1)
Posted inAstrochemistry
PAHSPECS: JWST/MIRI Spectroscopy Of PAHs at Cosmic Noon
[astro-ph.GA] The physical conditions of the interstellar medium (ISM) are thought to differ greatly at high redshifts compared to local galaxies. Polycyclic aromatic hydrocarbons (PAHs) are key ISM constituents, mediating […]
Posted inAstrochemistry
Chemists Uncover How Unthinkable Reactions Occur In Unimaginable Conditions
[Florida International University] Before there was Earth, there was chemistry. In the unimaginable cold, dark clouds where stars and planets are born, carbon molecules assemble into more complex forms — […]
Posted inAstrochemistry
Interstellar Aromatic Infrared Bands: IR Absorption Spectroscopy Of The Lowest Triplet State Of Naphthalene
[astro-ph.GA] The aromatic infrared bands (AIBs), emission features observed ubiquitously across a wide variety of interstellar objects, are commonly attributed to radiative cooling of highly-excited ground-state vibrational levels of polycyclic […]
Posted inVenus
Altered Cosmic Organics As Venus’ Ultraviolet Absorbers
[astro-ph.EP] Venus’ ultraviolet (UV) absorbers significantly contribute to the atmosphere’s energy budget. However, the composition of these absorbers remains a mystery.
![Schematic diagram of our spectral line stacking and matched filtering procedures. First, (a) shows relevant spectral regions of the (synthetic) observational data (black) and an initial spectral simulation (red). Each spectral window is then weighted based on the signal-to-noise ratio of each region to create a velocity stack of all relevant molecular rotational transitions (b). Finally, the stacked simulation is used as a matched filter and is cross-correlated with the stacked data to visualize the statistical significance of a given detection (c). -- [astro-ph.GA]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Exploring-the-Limits.png?resize=1200%2C720&ssl=1)
Posted inAstrochemistry
Exploring the Limits of Spectral Line Stacking in Spectral Line Data and Application Toward the Detection of Bulk 13C Enrichment of Aromatics in TMC-1
[astro-ph.GA] The formation history of polycyclic aromatic hydrocarbons (PAHs) in the interstellar medium remains a topic of active debate, with proposed mechanisms ranging from high-temperature stellar ejecta processes to low-temperature […]
![DFT-computed anharmonic absorption spectra of 1-cyanonaphthalene in its neutral (1-CNN0 , top panel), cation (1-CNN+ , middle panel), and anion (1-CNN− , bottom panel) charge states. The calculated vibrational transitions are convolved with a Lorentzian profile using a FWHM of 4 cm−1 to simulate realistic spectral profiles. Numerical labels near the major peaks represent their respective wavelengths. Key vibrational bands, including the CN stretch at ∼ 4.4–4.6 µm and the CH stretch at ∼ 3.2–3.3 µm, are explicitly highlighted.-- [astro-ph.GA]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/Anharmonic-Infrared-Emission.png?resize=1200%2C718&ssl=1)
Posted inAstrochemistry
Anharmonic Infrared Emission Of Cyano-Substituted Polycyclic Aromatic Hydrocarbon Molecules: Cyanonaphthalenes As A Case Study
[astro-ph.GA] Recent detections of cyano-substituted polycyclic aromatic hydrocarbons (cyano-PAHs) highlight them as key tracers of nitrogen heterocycles in the interstellar medium (ISM).
Posted inAtmospheres, Climate, Weather
Triassic Inferno: Fires Raged Across Europe For thousands Of Years During Past Global Warming
[Utrecht University] The end-Triassic mass extinction, 201 million years ago, is linked to volcanism that resulted from the break-up of Pangea and which pumped out vast amounts of CO2 into […]