A strong emission line at 2.8935μm discovered by Rubin et al. (2001) in an ISO SWS02 spectrum of the Orion Nebula is identified as the 4p P − 4s S multiplet of O i. Line formation is due to de-excitation cascades following UV-pumping of high S and D terms and occurs in the O i zone immediately behind the Hydrogen ionization front. This cascade mechanism also accounts for permitted O i triplet l...

We have observed sharp infrared spectral lines ( Deltanu approximately 60 MHz FWHM) in gamma-ray ionized para- H2 crystals. The lines are assigned to the Q1(0) transition of H2 near H+3 and H-, which becomes optically active and Stark shifted by the Coulomb fields of the ions. A simple model calculation gives a spectrum which agrees approximately with the observation. The spectrum stays the sam...

I Zwicky 1 (I Zw 1) is the prototype narrow line quasar. Its narrow line profiles minimize blending effects and thus allow a significantly more accurate study of individual quasar emission lines. We report here the results of our study of the 1150-3250 Å emission of I Zw 1 using a high S/N (50-120) spectrum obtained with the Faint Object Spectrograph (FOS) of the Hubble Space Telescope (HST). T...

The chemically peculiar star HR 1094 has been investigated with respect to its chemical composition and the magnetic influence on its stellar spectrum. By using spectral lines slightly affected by the field v sin i was determined to be ≤ 17 km s −1. The iron-group elements as well as chlorine and the heavy elements platinum, gold and mercury show an overabundance compared to the sun. The analys...

Abstract This work addresses a bottleneck usually encountered in the processing of large amounts LIBS data. It shows how fitting emission lines typical spectrum can be automated. is done by exploiting second derivative to obtain reasonable parameter estimates that, together with divide and conquer approach, used fit numbers crowded without user intervention executed within timeframe. As demonst...

We consider the properties of soft X-ray emission lines in the reprocessed emission from a photoionized accretion disc. Observations of these lines will be important in determining the ionization state and metallicity of the innermost regions of active galaxies. Calculations of reflection from a constant-density disc with an ionization parameter, ξ, between 250 and 1000 erg cm s show that emiss...

We have obtained a near infrared spectrum of the brightest satellite of the large Kuiper Belt Object, 2003 EL61. The spectrum has absorption features at 1.5 and 2.0 microns, indicating that water ice is present on the surface. We find that the satellite's absorption lines are much deeper than water ice features typically found on Kuiper Belt Objects. We argue that the unusual spectrum indicates...

It is shown that the "two-libron" lines in the Raman spectrum of solid hydrogen result from the large cubic anharmonicity of the quadrupole-quadrupole Hamiltonian. A localized picture is used to describe the interaction of two librational excitations on neighboring molecules, and dynamic interactions with other molecules are treated perturbatively. In this approximation the average single-libro...

We present new observations of the fundamental ro-vibrational CO spectrum of V1647 Ori, the young star whose recent outburst illuminated McNeil’s Nebula. Previous spectra, acquired during outburst in 2004 February and July, had shown the CO emission lines to be broad and centrally peaked—similar to the CO spectrum of a typical classical T Tauri star. In this paper, we present CO spectra acquire...

Stroemgren defined a model made up of an extremely hot source plunged in a constant density, huge, static cloud of low pressure hydrogen. The present studies of this model apply qualitatively with relatively small and cold sources, but without these assumptions, we must take into account that:-the source has, at all frequencies, the spectral radiance of a laser at a single frequency, so that th...