We use integral field spectroscopy with the Gemini North Telescope to detect probable fluorescent Lyα emission from gas lying close to the luminous QSO PSS 2155+1358 at redshift 4.28. The emission is most likely coming not from primordial gas, but from a multi-phase, chemically enriched cloud of gas lying about 50 kpc from the QSO. It appears to be associated with a highly ionised associated ab...

We present results from a survey of molecular hydrogen emission from a sample of Starburst and Seyfert galaxies carried out with the Infrared Space Observatory (ISO). Pure rotational H2 emission has been detected in a number of extragalactic objects and a variety of environments. A number of transitions from S(7) to S(0) are detected in both Starbursts and Seyferts. Using excitation diagrams we...

introduction energy is one of the most important commodities that make up a large proportion of international trade. among all the countries in the world, iran is known as semi-industrial developing country which is rich in energy such as non-renewable energy in particular fossil fuel. use of energy affects the environment in various forms of pollution. in the agricultural sector, the fao repor...

an increase in energy prices will decrease the fossil fuel consumption; on the other hand, the cost-push will encourage technology improvement for firms and households. these changes will affect the emission level.this paper studies the changes of yearly pollutant emissions after an energy price reform in iran. we apply a computable general equilibrium model which consists of 7 energy goods (el...

Small diesel engines are widely used for commercial vehicle and passenger car applications due to their higher torque requirements, fuel economy, and better thermal efficiency. These engines are exposed to different operating and environmental conditions and hence emissions from these engines are erratic. Strategies are required to enhance performance and reduce engine-out emissions considering...

The objective of the present experiment was to quantify the gas production parameters, methane emission and microbial nitrogen production of a conventional total mixed ration including corn silage, alfalfa hay, wheat straw and concentrate (390, 110, 22 and 478 g/kg of diet DM, respectively) treated with different levels of Natuzyme® and pre-incubation time after enzyme administration. Two hundr...

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 ...

We report on a recent Chandra ACIS-S observation of the Circinus galaxy. These observations confirm that the nuclear spectrum results from reflection of a hard X-ray continuum by “neutral” matter. The nuclear X-ray emission is extended by ∼ 60 pc in the general direction of the optical “ionization cone”. An image in the Fe Kα line has been made and shows that this emission extends up to 200 pc ...

We used a very large set of models of broad emission line (BEL) clouds in AGN to investigate the formation of the observed Fe II emission lines. We show that photoionized BEL clouds cannot produce both the observed shape and observed equivalent width of the 2200 – 2800Å Fe II UV bump unless there is considerable velocity structure corresponding to a microturbulent velocity parameter vturb ≥ 100...