Cosmological shock waves are a ubiquitous consequence of cosmic structure formation. They play a major role in heating baryonic gas in the large scale structure of the universe. In this contribution we study the shock-heated gas in connection with shocks themselves, using a set of N-body/hydrodynamic simulation data of a ΛCDM universe. The distributions of shock speed and temperature of shock-h...

This paper addresses the problem of reconstructing the 3D structure of planetary nebulae from 2D observations. Assuming axial symmetry, our method jointly reconstructs the distribution of dust and ionized gas in the nebulae from observations at two different wavelengths. In an inverse rendering framework we optimize for the emission and absorption densities which are correlated to the gas and d...

Amide-iminol tautomerism was studied for ionized oxamic acid (OA+•) in the gas phase using theDFT method with the UB3LYP functional and various basis sets {6-31++G(d,p), 6-311+G(d,p), and augcc-pVDZ}. Among twenty tautomers-rotamers possible for OA+•, eleven isomers were found to bethermodynamically stable. Similarly as for the neutral molecule, ionization (OA → OA+• + e) favors theamidization ...

Two long-slit spectra of the diffuse ionized gas in NGC 891 are presented. The first reveals variations parallel to the major axis in emission line ratios in the halo gas at z = 700 pc. It is found that filaments of Hα emission show lower values of [N II]/Hα, [S II]/Hα and [O I]/Hα. Although this result is expected if the filaments represent the walls of evacuated chimneys, it merely reflects a...

The circumnuclear disk and ionized gas filaments as remnants of tidally disrupted clouds Abstract. Sticky particle calculations indicate that a coherent structure , a dispersion ring, forms when a cloud on a low angular momentum orbit passes close to the dynamical center of a potential containing a point mass. The cloud is tidally stretched and differentially wrapped, and dissipation in shocks ...

Sub-arcsecond images, taken in B, R, and Hα filters, and area spectroscopy obtained with the WIYN 3.5-m telescope provide the basis for an investigation of the unusual structures in the stellar body and ionized gas in and around the Perseus cluster central galaxy, NGC 1275. Our Hα filter is tuned to gas at the velocity of NGC 1275, revealing complex, probably unresolved, small-scale features in...