Results 31 to 40 of about 1,184 (154)

Filtration of Interstellar Neutral Helium by Elastic and Charge Exchange Collisions in Heliospheric Boundaries

The Astrophysical Journal, 2023
Interstellar neutral (ISN) helium atoms penetrating the heliosphere are used to find the flow velocity and temperature of the very local interstellar medium near the heliosphere.
P. Swaczyna, F. Rahmanifard, E. J. Zirnstein, J. Heerikhuisen   +3 more
doaj   +1 more source

Charge State Influence on Stability and Isomerism in Dehydrogenated PAHs: Insights from Anthracene, Acridine, and Phenazine

ChemPhysChem, Volume 26, Issue 6, March 15, 2025.
The ionization of anthracene, acridine, and phenazine has been explored, along with the removal of one and two hydrogen atoms, to provide valuable information for astrochemists and to understand the behavior of the resulting structures and their electronic reorganization. Abstract In this study, we systematically explored the stability and isomerism of
Khaldia Zghida, Farouk Hamza Reguig, Manuel Alcamí, Al Mokhtar Lamsabhi   +3 more
wiley   +1 more source

Chemical Kinetics of 2‐, 4‐, and 2,4‐Seleno‐Uracils at Low Temperatures: Tautomerizations and Rotamerizations on Inert Matrices

International Journal of Chemical Kinetics, EarlyView.
ABSTRACT In the interstellar medium, chemical reactions proceed under conditions vastly different to those on Earth; these include extremely low temperatures and densities and take place in the gas phase and on water–ice grains. Understanding the energetics and more importantly the kinetics of such reactions is of relevance to the consequences on how ...
Judith Wurmel, John M. Simmie
wiley   +1 more source

Tiny-scale Properties within the Interstellar Medium toward PSR J1644−4559. I. Observational Evidence of Turbulence-induced Tiny-scale Atomic Structures

The Astrophysical Journal Supplement Series
We investigated H i absorption toward a single pulsar, PSR J1644−4559, and its variability over timescales from days to years, using Murriyang, CSIRO’s Parkes Radio Telescope.
Mengting Liu, Di Li, J. R. Dawson, Joel M. Weisberg, Snežana Stanimirović, George Hobbs, Simon Johnston, Lawrence Toomey, Siyao Xu, Chao-Wei Tsai, Donghui Quan, Stacy Mader, James A. Green, Lei Zhang, Ningyu Tang, Pei Wang, Kai Zhang, Pei Zuo, Gan Luo, Yi Feng, Shi Dai, Aditi Kaushik, Mengyao Xue, Chenchen Miao   +23 more
doaj   +1 more source

Dust and gas in star-forming complexes in NGC 3351, NGC 5055, and NGC 5457

Open Astronomy, 2023
We present a study of the interstellar medium parameters in star-forming complexes (SFCs) in NGC 3351, NGC 5055, and NGC 5457 galaxies. This study concludes our previous investigations of gas and dust in a number of spiral galaxies.
Smirnova Ksenia Ildarovna, Wiebe Dmitri Siegfriedovich   +1 more
doaj   +1 more source

Size Matters: Barrier Heights and Widths in the Kinetics Of Tautomerisation and Rotamerisation of Thiotropolone and Its Five‐ and Three‐Membered Cyclic Analogues

International Journal of Chemical Kinetics, EarlyView.
ABSTRACT Recent experiments by Nunes et al. have demonstrated that unprecedented control of chemical reactions is possible by narrowband infrared vibrational photo‐excitation at low temperatures in inert matrices. The generated higher energy level conformers may then undergo rotamerisation and tautomerisation reactions which provide extremely useful ...
Judith Wurmel, John M. Simmie
wiley   +1 more source

A Neutral Hydrogen Absorption Study of Cold Gas in the Outskirts of the Magellanic Clouds Using the GASKAP-H i Survey

The Astronomical Journal
Cold neutral hydrogen (H i ) is a crucial precursor for molecular gas formation and can be studied via H i absorption. This study investigates H i absorption in low column density regions of the Small and Large Magellanic Clouds (SMC and LMC) using the ...
Hongxing Chen, Snežana Stanimirović, Nickolas M. Pingel, James Dempsey, Frances Buckland-Willis, Susan E. Clark, Helga Dénes, John M. Dickey, Steven Gibson, Katherine Jameson, Ian Kemp, Denis Leahy, Min-Young Lee, Callum Lynn, Yik Ki Ma, N. M. McClure-Griffiths, Claire E. Murray, Hiep Nguyen, Lucero Uscanga, Jacco Th. van Loon, Enrique Vázquez-Semadeni   +20 more
doaj   +1 more source

Neutral Hydrogen (H i) 21 cm as a Probe: Investigating Spatial Variations in Interstellar Turbulent Properties

The Astrophysical Journal, 2023
Interstellar turbulence shapes the H i distribution in the Milky Way (MW). How this affects large-scale statistical properties of H i column density across the MW remains largely unconstrained.
Amit Kumar Mittal, Brian L. Babler, Snežana Stanimirović, Nickolas Pingel   +3 more
doaj   +1 more source

Cis–Trans Rotational Isomerism of Formic Acid, Sulfur, and Selenium Analogues and Their Dimers: Chemical Kinetics Under Interstellar Conditions

International Journal of Chemical Kinetics, EarlyView.
ABSTRACT We present chemical kinetic rate constants for the cis to trans isomerisation or rotamerization of monomeric seleno‐, thio‐, and formic acids and that of three of their dimeric species, based on variational transition state theory and multidimensional tunneling calculations in the gas‐phase, from 10 K to 300 K. These provide, firstly, reliable
Judith Wurmel, John M. Simmie
wiley   +1 more source

oMEGACat. VII. Tracing Interstellar and Intracluster Medium of ω Centauri Using Sodium Absorptions

The Astrophysical Journal
We investigate the foreground interstellar medium along the line of sight and intracluster medium of ω Centauri ( ω Cen) by measuring the equivalent width of Na I D absorptions from MUSE observations. The large line-of-sight velocity difference between ω
Z. Wang, A. C. Seth, M. Latour, J. Strader, M. Häberle, N. Neumayer, C. Clontz, S. Kamann, M. S. Nitschai, M. Alfaro-Cuello, A. Bellini, A. Feldmeier-Krause, M. Libralato, A. P. Milone, P. J. Smith, S. O. Souza, G. van de Ven   +16 more
doaj   +1 more source