First velocity-resolved [O I] 63/145 um maps of the Orion BN/KL outflow show broad components from dense warm postshock gas, with line ratios matching 30-40 km/s dissociative J-shocks illuminated by external UV, yielding [O I] luminosity 86.5 L_sun and mass-loss rate ~9e-3 M_sun/yr.
Investigating the Cosmic-Ray Ionization Rate in the Galactic Diffuse Interstellar Medium through Observations of H3+
3 Pith papers cite this work. Polarity classification is still indexing.
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abstract
Observations of H3+ in the Galactic diffuse interstellar medium (ISM) have led to various surprising results, including the conclusion that the cosmic-ray ionization rate (zeta_2) is about 1 order of magnitude larger than previously thought. The present survey expands the sample of diffuse cloud sight lines with H3+ observations to 50, with detections in 21 of those. Ionization rates inferred from these observations are in the range (1.7+-1.3)x10^-16 s^-1<zeta_2<(10.6+-8.2)x10^-16 s^-1 with a mean value of zeta_2=(3.5^+5.3_-3.0)x10^-16 s^-1. Upper limits (3 sigma) derived from non-detections of H3+ are as low as zeta_2<0.4x10^-16 s^-1. These low upper-limits, in combination with the wide range of inferred cosmic-ray ionization rates, indicate variations in zeta_2 between different diffuse cloud sight lines. A study of zeta_2 versus N_H (total hydrogen column density) shows that the two parameters are not correlated for diffuse molecular cloud sight lines, but that the ionization rate decreases when N_H increases to values typical of dense molecular clouds. Both the difference in ionization rates between diffuse and dense clouds and the variation of zeta_2 among diffuse cloud sight lines are likely the result of particle propagation effects. The lower ionization rate in dense clouds is due to the inability of low-energy (few MeV) protons to penetrate such regions, while the ionization rate in diffuse clouds is controlled by the proximity of the observed cloud to a site of particle acceleration.
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UNVERDICTED 3representative citing papers
HINSA observations show CRIR decreasing with H2 column density in both clouds, with IC 348 values an order of magnitude above NGC 1333, modeled as an order-of-magnitude difference in low-energy CR populations from local acceleration sources.
Bayesian inference on ALMA observations with a neural network emulator for chemical models reveals radial and azimuthal variations in gas density, temperature, column density, and cosmic-ray ionization rate across NGC 1068.
citing papers explorer
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Velocity-resolved [O I] 63,145 um, [C II] 158 um, and OH mapping along the Orion BN/KL explosive outflow and irradiated shocks
First velocity-resolved [O I] 63/145 um maps of the Orion BN/KL outflow show broad components from dense warm postshock gas, with line ratios matching 30-40 km/s dissociative J-shocks illuminated by external UV, yielding [O I] luminosity 86.5 L_sun and mass-loss rate ~9e-3 M_sun/yr.
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A HINSA view of cosmic-ray ionization in IC 348 and NGC 1333: evidence for a strong low-energy cosmic-ray disparity
HINSA observations show CRIR decreasing with H2 column density in both clouds, with IC 348 values an order of magnitude above NGC 1333, modeled as an order-of-magnitude difference in low-energy CR populations from local acceleration sources.
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Physical and Chemical Conditions of Molecular Gas in NGC 1068: The nuclear feedback in the circumnuclear disk and starburst ring
Bayesian inference on ALMA observations with a neural network emulator for chemical models reveals radial and azimuthal variations in gas density, temperature, column density, and cosmic-ray ionization rate across NGC 1068.