20 papers · 1 filter
Resolving dense photodissociation regions: the structure of photochemical fronts in three-dimensional gas distributions
Brandt A. L. Gaches, Thomas G. Bisbas, Lothar Brendel +1
For decades, the Orion Bar has been the prototypical photodissociation region. Viewed nearly edge-on, it offers a unique window into the stratified chemical structure of the atomic…
Anomalously high deuterium fractionation in a galactic translucent cloud: a challenge to chemical models
Gan Luo, Zhi-Yu Zhang, Thomas G. Bisbas +8
Deuterated (D-) species have long been proposed to diagnose the physical conditions and chemical evolution of cold dense molecular clouds. While deuterium fractionation has been ex…
A HINSA view of cosmic-ray ionization in IC 348 and NGC 1333: evidence for a strong low-energy cosmic-ray disparity
Gan Luo, Marco Padovani, Daniele Galli +5
The cosmic-ray ionization rate (CRIR) is one of the fundamental parameters influencing the chemical and dynamical evolution of molecular clouds. Although observations in recent yea…
Star Formation Drives Production of Low Energy Cosmic Rays
Ningyu Tang, Jiahao Liu, Di Li +18
For over a century, the origin of low-energy cosmic rays (LECRs), the dominant heaters and ionizers of dense interstellar gas, remains elusive owing to solar modulation and uncerta…
Large scale mapping of [CI] and the [CI]-to-CO transition in Ophiuchus molecular cloud
Jifeng Xia, Ningyu Tang, Thomas G. Bisbas +10
Atomic carbon ([CI]) is a key species in the carbon chemistry of the interstellar medium (ISM). Using the Submillimeter Wave Astronomy Satellite (SWAS), we conducted a [CI](P$_…
JWST observations of cosmic-ray-excited H in Barnard 68: spatial variations and constraints on cosmic-ray attenuation
David A. Neufeld, Kedron Silsbee, Alexei V. Ivlev +9
We present James Webb Space Telescope (JWST) NIRSpec observations of the starless dark cloud Barnard 68 that reveal the spatially-resolved signature of cosmic-ray excited molecular…