English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

A study of the interstellar medium (ISM) and cosmic rays (CRs) using FermiLarge Area Telescope (LAT) data, in a region encompassing the nearby molecularclouds MBM 53, 54, and 55 and a far-infrared loop-like structure in Pegasus, isreported. By comparing Planck dust thermal emission model with Fermi-LATgamma-ray data, it was found that neither the dust radiance (R) nor the dustopacity at 353 GHz (tau353) were proportional to the total gas column densityN(Htot) primarily because N(Htot)/R and N(Htot)/tau353 depend on the dusttemperature (Td). The N(Htot) distribution was evaluated using gamma-ray databy assuming the regions of high Td} to be dominated by optically thin atomichydrogen (HI) and by employing an empirical linear relation of N(Htot)/R to Td.It was determined that the mass of the gas not traced by the 21-cm or 2.6-mmsurveys is ~25% of the mass of HI in the optically thin case and is larger thanthe mass of the molecular gas traced by carbon monoxide by a factor of up to 5.The measured gamma-ray emissivity spectrum is consistent with a model based onCR spectra measured at the Earth and the nuclear enhancement factor of <=1.5.It is, however, lower than local HI emissivities reported by previous Fermi-LATstudies employing different analysis methods and assumptions on ISM propertiesby 15%-20% in energies below a few GeV, even if we take account of thestatistical and systematic uncertainties. The origin of the discrepancy is alsodiscussed.

astrophysical journal/the astrophysical journal

Quantifying the Interstellar Medium and Cosmic Rays in the MBM 53, 54,  and 55 Molecular Clouds and the Pegasus Loop using Fermi-LAT Gamma-ray  Observations