An attempt is made to synthesize the intrinsic hydrogen line spectrum of QSOs. These observations allow the determination of the hydrogen L.cap alpha./Balmer line ratios in high redshift objects and the P.cap alpha./Balmer line ratios in low redshift objects. « lessĬombined optical and infrared spectrophotometry of the emission line spectra of 14 QSOs are presented. These properties and others that we find in this work could lead to misidentification of lines or misattribution of properties of line-forming material at post-photospheric times in SN optical spectra. Most notably, resonance lines in these conditions form P Cygni-like profiles, but the emission peaks and absorption troughs shift redward and blueward, respectively, from the line's rest wavelength by a significant amount, despite the spherically symmetric distribution of the line optical depth in the ejecta.
#Spectra line formation code#
Our comparisons with analogous results from the Elementary Supernova code SYNOW reveal several marked differences in line formation. We develop the mathematical framework necessary for solving the radiative transfer equation under these conditions and calculate spectra for both isolated and blended lines. To explore this possibility, we present a geometrical approach to SN spectrum formation based on the 'Elementary Supernova' model, wherein we investigate the characteristics of resonance-scattering in optically thick lines while more » replacing the photosphere with a transparent central core emitting non-blackbody continuum radiation, akin to the optical continuum provided by decaying Co formed during the explosion. However, evidence exists that suggests that some spectra exhibit line profiles formed via optically thick resonance-scattering even months or years after the SN explosion. Most treatments and analyses of post-photospheric optical spectra of SNe assume that forbidden-line emission comprises most if not all spectral features. In supernova (SN) spectroscopy relatively little attention has been given to the properties of optically thick spectral lines in epochs following the photosphere's recession. Assuming optically thin formation with the standard coronal approximation leads to several errors: neglecting photoionization severly underestimates the amount of C ii at temperatures below 16 kK, erroneously shifts the formation from 10 kK to 25 kK, and leads to too low intensities. The smaller opacity broadening happens for single peak intensity profiles where the chromospheric temperature is low with a steep source function increase into the transition region, the larger broadening happens when there is a temperature increase from the photosphere to the low chromosphere leading to a local source function maximum and a double peak intensity profile with a central reversal. The lines are 1.2–4 times wider than the atomic absorption profile due to the formation in the optically thick regime. The core intensity is formed in layers where the temperature is about 10 kK at the base of the transition region. The lines are formed in the optically thick regime. 3D scattering effects are important for more » the intensity in the core of the line. We find that a nine-level model atom of C i–C iii with the transitions treated assuming complete frequency redistribution (CRD) suffices to describe the C ii 133.5 nm lines. We here develop such a model atom and we study the general formation properties of the C ii lines. To make three-dimensional (3D) non-LTE radiative transfer computationally feasible, it is crucial to have a model atom with as few levels as possible while retaining the main physical processes.
The C ii 133.5 nm lines are important observables for the NASA/SMEX mission Interface Region Imaging Spectrograph.
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