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The forward fitting of solar flare observations with radiation-hydrodynamic simulations is a common technique for learning about energy deposition and atmospheric evolution during these explosive events. A frequent spectral line choice for…

Solar and Stellar Astrophysics · Physics 2021-08-11 Christopher M. J. Osborne , Petr Heinzel , Jana Kašparová , Lyndsay Fletcher

We introduce non-equilibrium molecular hydrogen chemistry into the radiation hydrodynamics code Ramses-RT. This is an adaptive mesh refinement grid code with radiation hydrodynamics that couples the thermal chemistry of hydrogen and helium…

Astrophysics of Galaxies · Physics 2018-09-07 Sarah Nickerson , Romain Teyssier , Joakim Rosdahl

We present a systematic study of deuterated molecular hydrogen (HD) at high redshift, detected in absorption in the spectra of quasars. We present four new identifications of HD lines associated with known $\rm H_2$-bearing Damped…

Astrophysics of Galaxies · Physics 2021-06-30 D. N. Kosenko , S. A. Balashev , P. Noterdaeme , J. -K. Krogager , R. Srianand , C. Ledoux

We study the chemistry of small hydrocarbons in the photon-dominated regions (PDRs) associated with the ultra-compact HII region Mon R2. Our goal is to determine the variations of the abundance of small hydrocarbons in a high-UV irradiated…

Recent Herschel and ALMA observations of Photodissociation Regions (PDRs) have revealed the presence of a high thermal pressure (P ~ 10^7-10^8 K cm-3) thin compressed layer at the PDR surface where warm molecular tracer emission (e.g. CH+,…

Astrophysics of Galaxies · Physics 2018-01-08 Emeric Bron , Marcelino Agúndez , Javier R. Goicoechea , José Cernicharo

We present [Ci] and [Cii] observations of a linear edge region in the Taurus molecular cloud, and model this region as a cylindrically symmetric PDR exposed to a low-intensity UV radiation field. The sharp, long profile of the linear edge…

Astrophysics of Galaxies · Physics 2015-06-22 Matthew Orr , Jorge Pineda , Paul Goldsmith

Prompt photon measurements in relativistic nuclear collisions serve as an essential comparative basis for heavy ion studies enabling the separation of medium induced effects. However, the identification of prompt photons is experimentally…

Nuclear Theory · Physics 2025-10-20 Sinjini Chandra , Rupa Chatterjee , Zubayer Ahammed

We present the NLO QCD corrections to diphoton plus jet production at hadron colliders. Our calculation includes contributions from the fragmentation of a hadronic jet into a highly energetic photon, and consequently allows the…

High Energy Physics - Phenomenology · Physics 2014-05-14 T. Gehrmann , N. Greiner , G. Heinrich

Water is an important molecule in interstellar and circumstellar environments. Previous observations of mid-infrared rotational lines of OH suggest that these lines may be used to probe the photodissociation of water. In this work, cross…

Astrophysics of Galaxies · Physics 2021-06-30 Benoît Tabone , Marc C. van Hemert , Ewine F. van Dishoeck , John H. Black

Ultracompact (UC) HII regions constitute one of the earliest phases in the formation of a massive star and are characterized by extreme physical conditions (Go>10^5 Habing field and n>10^6 cm^-3). The UC HII Mon R2 is the closest one and…

Photodissociation regions (PDRs) and shocks give rise to conspicuous emission from rotationally and vibrationally excited molecular hydrogen. This line emission has now been studied with ISO and from the ground in great detail. A remarkable…

With plasma shielding effects of the Debye-H\"uckel model, we investigate the relativistic photoionization processes of H, Nb$^{40+}$ and Pb$^{81+}$ plasmas in the H-isoelectronic series. The shielded nuclear potential of Yukawa-type…

Atomic Physics · Physics 2020-01-06 Xugen Zheng , Hsin-Chang Chi , Shin-Ted Lin , Gang Jiang , Chenkai Qiao , Keh-Ning Huang

Within a dynamical model, rescattering effects are studied in coherent pion photoproduction on the deuteron in the $\Delta$(1232) resonance region. The model consists of a system of coupled equations for the N$\Delta$, NN$\pi$ and NN…

Nuclear Theory · Physics 2009-10-30 P. Wilhelm , H. Arenhoevel

Mon R2, at a distance of 830 pc, is the only ultracompact HII region (UC HII) where the photon-dominated region (PDR) between the ionized gas and the molecular cloud can be resolved with Herschel. HIFI observations of the abundant compounds…

We present a study of the photochemistry of abiotic habitable planets with anoxic CO$_2$-N$_2$ atmospheres. Such worlds are representative of early Earth, Mars and Venus, and analogous exoplanets. H$_2$O photodissociation controls the…

Earth and Planetary Astrophysics · Physics 2020-07-01 Sukrit Ranjan , Edward W. Schwieterman , Chester Harman , Alexander Fateev , Clara Sousa-Silva , Sara Seager , Renyu Hu

Radiative cooling by molecules is a crucial process for hydrodynamic escape, as it can efficiently remove the thermal energy driving the outflow, acquired through X-ray and extreme UV absorption. Carbon oxides, such as CO and CO2, and their…

Earth and Planetary Astrophysics · Physics 2024-11-26 Tatsuya Yoshida , Naoki Terada , Kiyoshi Kuramoto

We have developed a three dimensional Monte Carlo photoionization code tailored for the study of Galactic H II regions and the percolation of ionizing photons in diffuse ionized gas. We describe the code, our calculation of photoionization,…

Astrophysics · Physics 2009-11-10 K. Wood , J. Mathis , B. Ercolano

We derive an expression for the total photodissociation cross section of a molecule incorporating both indirect processes that proceed through excited resonances, and direct processes. We show that this cross section exhibits generalized…

Condensed Matter · Physics 2015-06-24 Y. Alhassid , Y. V. Fyodorov , T. Gorin , W. Ihra , B. Mehlig

Steric effect in the threshold dissociative ionizations of serine conformers [CH2OH-C\alphaH(NH2)-C\betaOOH] is revealed by high-level ab initio calculations combined with our newly developed infrared laser desorption / tunable VUV…

Chemical Physics · Physics 2008-07-02 Shan Xi Tian , Jinlong Yang , Hai-Bei Li , Yang Pan , Taichang Zhang , Liusi Sheng

Water photodissociation in the 114 - 144 nm UV range forms excited OH which emits at mid-infrared wavelengths via highly excited rotational lines. These lines have only been detected with Spitzer in several proto-planetary disks and shocks.…

Astrophysics of Galaxies · Physics 2023-03-08 Marion Zannese , Benoît Tabone , Emilie Habart , Franck Le Petit , Ewine F. van Dishoeck , Emeric Bron