Results 41 to 50 of about 345 (143)

Emergence of Optical Activity and Surface Morphology Changes in Racemic Amino Acid Films Under Circularly Polarized Lyman‐α Light Irradiation

open access: yesChirality, Volume 36, Issue 11, November 2024.
The photoreaction induced by Lyman‐α circularly polarized light (CPL) irradiation in racemic alanine film is more complex than simple preferential photolysis of enantiopure alanine molecules, and formation of larger molecules is observed. Circular networks of order of 100 nm scale are introduced in the alanine film surface by the irradiation.
Masahiro Kobayashi   +10 more
wiley   +1 more source

Two‐Step Electron Acceleration During a Flux Rope Crossing of Earth's Bow Shock

open access: yesGeophysical Research Letters, Volume 51, Issue 17, 16 September 2024.
Abstract The generation of cosmic ray particles with ultra‐relativistic energies is a crucial issue in astrophysical and space physics. Shocks have been acknowledged as efficient accelerators in the universe which can produce energetic particles through a variety of mechanisms, such as diffusive shock acceleration (DSA), shock surfing acceleration (SSA)
D. K. Hu   +3 more
wiley   +1 more source

Gamma-Ray Burst Interaction with the Circumburst Medium: The CBM Phase Following the Prompt Phase in GRBs

open access: yesThe Astrophysical Journal
Progenitor stars of long gamma-ray bursts (GRBs) could be surrounded by a significant and complex nebula structure lying at a parsec-scale distance. After the initial release of energy from the GRB jet, the jet will interact with this nebula environment.
Asaf Pe’er, Felix Ryde
doaj   +1 more source

Electron microscopy observations of the diversity of Ryugu organic matter and its relationship to minerals at the micro‐ to nano‐scale

open access: yesMeteoritics &Planetary Science, Volume 59, Issue 8, Page 2023-2043, August 2024.
Abstract Transmission electron microscopy analyses of Hayabusa2 samples show that Ryugu organic matter exhibits a range of morphologies, elemental compositions, and carbon functional chemistries consistent with those of carbonaceous chondrites that have experienced low‐temperature aqueous alteration.
Rhonda M. Stroud   +112 more
wiley   +1 more source

Model for Synchrotron Emission from Shell Supernova Remnants in Nonuniform Interstellar Medium and Nonuniform Magnetic Field

open access: yes, 2002
6 pages. Contribution to the conference "Selected tasks in Astronomy and Astrophysics" (Lviv, April 2002)
openaire   +2 more sources

Coevolution of phyllosilicate, carbon, sulfide, and apatite in Ryugu's parent body

open access: yesMeteoritics &Planetary Science, Volume 59, Issue 8, Page 2073-2096, August 2024.
Abstract We analyzed an asteroid Ryugu sample returned to Earth by JAXA's Hayabusa2 mission using nanoIR, SEM, and TEM microscopy. We identified multiple distinct carbon reservoirs within the phyllosilicate matrix and demonstrate infrared spectral affinities for some of the carbon to insoluble organic matter (IOM).
Zack Gainsforth   +31 more
wiley   +1 more source

Synchrotron Break Frequencies of Mildly to Highly Relativistic Outflows Observed Off-axis

open access: yesThe Astrophysical Journal
We consider the synchrotron spectrum produced by mildly to highly relativistic collisionless shocks. Simple analytic formulae are derived for the break frequencies (peak frequency, self-absorption frequency, synchrotron, and inverse Compton cooling ...
Gilad Sadeh
doaj   +1 more source

Possible Evidence for Extended X-Ray Emission Surrounding PSR B0656+14 with eROSITA

open access: yesThe Astrophysical Journal
Extended very-high-energy γ -ray emission from middle-aged pulsars as revealed recently by several ground-based γ -ray experiments has strong implication on the transport of high-energy particles in the interstellar medium surrounding those pulsars.
Shu Niu   +5 more
doaj   +1 more source

A Catalog of Filaments in the Central Molecular Zone

open access: yesThe Astrophysical Journal Supplement Series
We present a catalog of 1.28 GHz radio filaments observed by MeerKAT over the innermost 200 pc of the Galaxy (roughly ±1 $\mathop{.}\limits^{\unicode{x000b0}}$ 5), which includes the central molecular zone.
Richard G. Arendt   +2 more
doaj   +1 more source

Probing Three-dimensional Magnetic Fields. III. Synchrotron Emission and Machine Learning

open access: yesThe Astrophysical Journal
Synchrotron observation serves as a tool for studying magnetic fields in the interstellar medium and intracluster medium, yet its ability to unveil three-dimensional (3D) magnetic fields, meaning probing the field’s plane-of-the-sky (POS) orientation ...
Yue Hu, A. Lazarian
doaj   +1 more source

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