We have observed the planetary nebula NGC 2440 in the transitions [O II] λ3727, He II λ4686, [O III] λλ(4363+5007), H I λλ(4861+6563), He I λ5876, [N II] λ6584, [S II] λλ(6717+6731), and [S III] λ9061, as well as in various continuum filters. As a result, we are able to evaluate the excitation structure of the source and determine the projected

Gravitational lensing is a powerful astrophysical and cosmological probe and is particularly valuable at submillimeter wavelengths for the study of the statistical and individual properties of dusty star-forming galaxies. However, the identification of gravitational lenses is often time-intensive, involving the sifting of large volumes of imaging

We use deep Herschel Space Observatory observations of a 90 per cent complete sample of 32 intermediate-redshift 2Jy radio galaxies (0.05 z 0.7) with strong emission lines to estimate the dust masses of their host galaxies and thereby investigate the triggering mechanisms for their quasar-like AGN. The dust masses derived for the radio galaxies

We present the high-resolution spectroscopic study of five -3.9 ≤ [Fe/H] ≤ -2.5 stars in the Local Group dwarf spheroidal, Sculptor, thereby doubling the number of stars with comparable observations in this metallicity range. We carry out a detailed analysis of the chemical abundances of α, iron peak, and light and heavy elements, and draw

We present results from the EDGE survey, a spatially resolved CO(1‑0) follow-up to CALIFA, an optical Integral Field Unit survey of local galaxies. By combining the data products of EDGE and CALIFA, we study the variation in molecular gas depletion time (τ dep) on kiloparsec scales in 52 galaxies. We divide each galaxy into two parts: the center

The effect of scattering processes in the continuum on the formation of spectral lines in a static atmosphere with an arbitrary distribution of the internal energy sources is investigated using Ambartsumian's principle of invariance. Spectral line profiles are calculated to illustrate the effect the assumption of the complete redistribution on