相关论文: Helium recombination spectra as temperature diagno…

In this work, two aspects of the chemical evolution of 4He in the Galaxy are considered on the basis of a sample of disk planetary nebulae (PN). First, an application of corrections owing to the contamination of 4He from the evolution of…

While solar flares are predominantly characterised by an intense broadband enhancement to the solar radiative output, certain spectral lines and continua will, in theory, exhibit flare-induced dimmings. Observations of transitions of…

The spatial structure of the emission lines and continuum over the 50 arcsecond extent of the nearby, O-rich, planetary nebula NGC 7009 (Saturn Nebula) have been observed with the MUSE integral field spectrograph on the ESO Very Large…

We present multi-configuration Breit-Pauli AUTOSTRUCTURE calculations of distorted-wave photoionization (PI) cross sections, and total and partial final-state resolved radiative recombination (RR) and dielectronic recombination (DR) rate…

Possibility for coexistence of a phonon and one-particle spectra in ${}^4He$ at all temperatures including temperatures below the $\lambda$ - point is shown. An approach developed to consider the problem of the weakly imperfect Bose gas…

We present deep echelle spectrophotometry of the Galactic {\hii} regions M16, M20 and NGC 3603. The data have been taken with the Very Large Telescope Ultraviolet-Visual Echelle Spectrograph in the 3100 to 10400 \AA range. We have detected…

We report detailed analyses of deep, high-resolution spectra of three Galactic planetary nebulae (PNe) with high abundance discrepancy factors (ADFs), Hf2-2, M1-42 and NGC6153, obtained with the Ultraviolet and Visual Echelle Spectrograph…

We present high sensitivity H91$\alpha$ and 3.5 cm radio continuum observations toward the planetary nebula NGC 3242. The electron temperature determined assuming local thermodynamic equilibrium is consistent within $\sim$10% with that…

Helium ionization plays an important role in the energy balance of the upper chromosphere and transition region. Helium spectral lines are also often used as diagnostics of these regions. We carry out 1D radiation-hydrodynamics simulations…

We present echelle spectrophotometry of the Galactic H II region S 311. The data have been taken with the Very Large Telescope UVES echelle spectrograph in the 3100 to 10400 angstroms range. We have measured the intensities of 263 emission…

Large-amplitude electrostatic fluctuations are routinely observed by spacecraft upon traversal of collisionless shocks in the heliosphere. Kinetic simulations of shocks have struggled to reproduce the amplitude of such fluctuations,…

Echelle spectrophotometry of the 30 Doradus nebula in the LMC is presented. The data consists of VLT UVES observations in the 3100 to 10350 A range. The intensities of 366 emission lines have been measured, including 269 identified…

The nebular phase of lanthanide-rich ejecta of a neutron star merger (NSM) is studied by using a one-zone model, in which the atomic properties are represented by a single species, neodymium (Nd). Under the assumption that beta-decay of…

In the recent work Fletcher et al. [Phys. Rev. Lett., v.99, p.145001 (2007)] reported on the novel experimental technique, enabling to measure the temperature of the expanding ultracold plasmas over a considerable time interval (up to 60-70…

Photoionization models of the giant HII region 30 Doradus are built and confronted to available UV, optical, IR (ISO) and radio spectra, under black-body or CoStar SEDs for the primary source and various density distributions for the…

We propose a methodology to perform a self-consistent analysis of the physical properties of the emitting gas of HII galaxies adequate to the data that can be obtained with the XXI century technology. This methodology requires the…

Context: In recent years mid- and far infrared spectra of planetary nebulae have been analysed and lead to more accurate abundances. It may be expected that these better abundances lead to a better understanding of the evolution of these…

Star-forming galaxies with nebular HeII emission contain very energetic ionizing sources of radiation, which can be considered as analogs to the major contributors of the reionization of the Universe in early epochs. It is therefore of…

We present a first study based on the analysis of the DEep Spectra of Ionized REgions Database (DESIRED). This is a compilation of 190 high signal-to-noise ratio optical spectra of HII regions and other photoionized nebulae, mostly observed…

We present integral field unit spectroscopic observations of southern Galactic planetary nebulae (PNe), IC 2501, Hen 2-7, and PB4. The goal of studying these objects together is that, although they have roughly similar intermediate…