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Item Realistic energy deposition and temperature heating in molecular clouds due to cosmic rays: a computation simulation with the GEANT4 code employing light particles and medium-mass and heavy ions(Royal Astronomical Society) Pilling, Sergio; Pazianotto, Maurício Tizziani; Souza, Lucas Alves de; Nascimento, Larissa Maciel doIn the interstellar medium, Galactic and extragalactic cosmic rays (CRs) penetrate deeper in the molecular clouds (MCs) and promote inside several physical and physicochemical changes due to the energy deposition, including gas and grain heating, and triggering also molecular destruction and formation. In this work, in an attempt to simulate, in a more realistic way, the energy delivered by CRs in a typical MC (mass ∼5400 M and size ∼106 au; mainly composed of H atoms), we combine the energy deposition of light particles and heavy ions, with the new calculations considering the medium-mass ions (3 ≤ Z ≤ 11). To execute the calculation, the Monte Carlo toolkit GEANT4 was applied to get the energy deposition rate per mass from many kinds of secondary particles, used in nuclear and hadron physics. The energy deposition by its induced cascade shower within the MC was characterized, as well as the relative energy deposition for all members of the medium-mass group. The results show that the incoming protons are the dominant source in the energy deposition and heating of the cloud, followed by alphas and electrons, with the medium-mass-ion and heavy-ion groups each contributing roughly 8 per cent. The current model also shows a temperature enhancement of up to 10 per cent in the external layers of the cloud (reaching 22.5 K) with respect to the previous calculations where only light particles were considered. However, neither heavy nor medium-mass ions contribute to the temperature enhancement in the deep core of the cloud.Item The Influence of Heavy Cosmic Rays in Energy Deposition in Molecular Clouds Employing the GEANT4 Code and Voyager I Data(IOP science) Pilling, Sergio; Pazianotto, Maurício Tizziani; Souza, Lucas Alves deGalactic and extragalactic cosmic rays fully illuminate and trigger several physical and physicochemical changes in molecular clouds (MCs), including gas and grain heating, molecular destruction and formation, and molecular and atomic desorption (sputtering) from dust/ices to gas phase. Besides the major component in cosmic ray inventory (in flux) being electrons, protons, and alphas, particles with larger atomic numbers have a higher rate of energy delivery (due to richer cosmic ray showers) than the lighter particles, and this may add extra energy input into MCs. To understand this issue, we perform complementary calculations to the previous work on MCs, now adding the heavy ions (12 ≤ Z ≤ 29) in the cosmic ray incoming inventory. Once more, the calculations were performed employing the Monte Carlo toolkit GEANT4 code (considering nuclear and hadron physics). We observe that most projectiles in the heavy ion group have lower deposited energies (roughly 10 times less) than iron with the exception of magnesium (Z = 12) and silicon (Z = 14) which are about double. Cobalt presents the lowest deposited energies with respect to iron (only 0.5%). The total energy deposition in the current model was only roughly 10% higher (outer layers) and virtually the same at the center of the cloud when compared with the previous model (with only protons + alphas + electrons sources). The results show that energy deposition by heavy ions is small compared with the values from light particles, and also suggest a very low temperature enhancement due to heavy ions within the MC, being the protons the dominant agent in the energy delivery and also in the cloud's heating.