NGC6543 is one of the few planetary nebulae (PNe) whose X-ray emission has been shown to be extended and originate from hot interior gas. Using FUSE observations we have now detected nebular O VI emission from NGC6543. Its central star, with an effective temperature of ∼50,000 K, is too cool to photoionize O V, so the O VI ions must have been produced by thermal collisions at the interface betw...

The majority of nearby early-type galaxies contains detectable amounts of emission-line gas at their centers. The emission-line ratios and gas kinematics potentially form a valuable diagnostic of the nuclear activity and gravitational potential well. The observed central gas velocity dispersion often exceeds the stellar velocity dispersion. This could be due to either the gravitational potentia...

In order to study the origin of the strong Lyα emission of high-redshift starburst galaxies we observed and modeled the emission of the z = 3.304 galaxy FDF-4691 (rest-frame EWLyα = 103 Å). The observations show that FDF-4691 is a young starburst galaxy with a (for this redshift) typical metallicity. The broad, double-peaked profile of the Lyα emission line can be explained assuming a highly tu...

Citation: Feltre A, Charlot S, Mignoli M, Bongiorno A, Calura F, Chevallard J, Curtis-Lake E, Gilli R and Plat A (2017) Ultraviolet/Optical Emission of the Ionized Gas in AGN: Diagnostics of the Ionizing Source and Gas Properties. Front. Astron. Space Sci. 4:32. doi: 10.3389/fspas.2017.00032 Ultraviolet/Optical Emission of the Ionized Gas in AGN: Diagnostics of the Ionizing Source and Gas Prope...

One of the major factors, contributing to the emission of greenhouse gases in the environment is generation of pollutant gases in municipal landfills. As for the design and building of a gas collecting system, it is necessary to properly estimate the amount and type of the landfill emissions. By means of LandGEM model, this study predicts the amount and type of the landfill gases, produced for ...

There are many coal seams in high-gas mining area of China. The permeability is low. The gas extraction from the original coal seam is difficult and the commercial value is little. The conception of the safe high-efficient exploitation of coal and gas is put forward in this article. It changes the conventional exploitation sequence that is from the upper to below. When we exploit coal seams, th...

High spatial resolution, narrow band, infrared line images and CO (1—0) mm interferometer data are presented for NGC 7027. These data trace emission from the central H II region (Bra), the intermediate photodissociation region [H2 1—0S(1) and 3.3 /im dust feature], and the molecular circumstellar envelope [CO (1—0)]. The H II region lies in a cavity in the CO envelope, and consists of a smooth ...

Observations are presented showing the doublet C ivλλ1548, 1551 absorption lines superimposed on the C iv emission in the radio galaxy 0943–242. Within the errors, the redshift of the absorption system that has a column density of NCIV = 1014.5±0.1 cm−2 coincides with that of the deep Lyα absorption trough observed by Röttgering et al. (1995). The gas seen in absorption has a resolved spatial e...

We have analyzed observations with the Chandra X-ray Observatory of the diffuse emission by hot gas in 7 dwarf starburst galaxies, 6 edge-on starburst galaxies, and 9 Ultra Luminous Infrared Galaxies. These systems cover ranges of ∼ 10 4 in X-ray luminosity and several thousand in star formation rate and K-band luminosity (a proxy for stellar mass). Despite this range in fundamental parameters,...

In the fall of 2016, a field study was conducted in the Uinta Basin Utah to improve information on oil and natural gas well pad pneumatic controllers (PCs) and emission measurement methods. A total of 80 PC systems at five oil sites (supporting six wells) and three gas sites (supporting 12 wells) were surveyed, and emissions data were produced using a combination of measurements and engineering...