Related papers: Some Common Problems and Challenges that Emission-…
We have performed 5 night spectroscopic observation of the Halpha line of EV Lac with a medium wavelength resolution (R~ 10,000) using the 2m Nayuta telescope at the Nishi-Harima Astronomical Observatory. EV Lac always possesses the Halpha…
High resolution line profiles are presented for selected forbidden and permitted emission lines of a sample of galactic B[e]-type stars. The spectral resolution corresponds to 5-7 km/s with the exception of some line profiles which were…
Aims: To investigate the spectra and the evolutionary stages of two peculiar emission-line stars: RJHA 49 and SS73 21. Methods: We used low and high resolution optical data. Line identifications and measurements were performed for several…
As a characteristic feature of the spectrum, the emission line carries critical information on the underlying physics of the radiation. After extensive efforts in decades, the first high-significant detection of a series of emission lines…
The Early Universe Molecular Emission Line Galaxies (EMGs) are a population of galaxies with only 36 examples that hold great promise for the study of galaxy formation and evolution at high redshift. The classification, luminosity of…
As a byproduct of its search for the first star forming galaxies, NGST will obtain high-quality spectra for thousands of galaxies in the redshift range z = 0 - 6 and beyond. Most of the galaxies will possess strong emission-line spectra,…
Splitting of the strongest absorption lines with a lower-level excitation potential $\chi<$1eV has been detected for the first time in the optical spectra of the post-AGB star V354Lac obtained with a spectral resolution R=60000 at the 6-m…
Although about a dozen high redshift (z larger than 2) starburst galaxies have been recently detected in the CO lines, spectroscopic detections of molecular gas of very young galaxies are still very difficult. The CO lines are usually…
We present the first medium-resolution ($R\sim 600$) mid-infrared (8-13.3\micron) spectra of 11 Be stars. A large number of lines are observed and identified in these spectra, including, as an example, 39 hydrogen recombination lines in the…
This paper discusses a model where a violent periastron collision of stars in an eccentric binary system induces an eruption or explosion seen as a brief transient source, attributed to LBVs, SN impostors, or other transients. The key…
Extensive spectral observations of eta Carinae over the last cycle, and particularly around the 2003.5 low excitation event, have been obtained. The variability of both narrow and broad lines, when combined with data taken from two earlier…
As the James Webb Space Telescope approaches scientific operation, there is much interest in exploring the redshift range beyond that accessible with Hubble Space Telescope imaging. Currently, the only means to gauge the presence of such…
The nature of the tenuous disks around A stars has raised considerable controversy in the literature during the past decade. The debate whether or not the disk around beta Pictoris contains gaseous molecular hydrogen is only the most recent…
The duration of the prompt emission of long gamma-ray bursts is generally considered to be fairly similar to the duration of the activity of the engine in the center of the progenitor star. Here, we investigate the relation between the…
The evidence for spectral features in gamma-ray bursts is summarized. As a guide for evaluating the evidence, the properties of gamma-ray detectors and the methods of analyzing gamma-ray spectra are reviewed. In the 1980's, observations…
Spitzer observations of SN 1987A have now spanned more than a decade. Since day ~4,000, mid-infrared (mid-IR) emission has been dominated by that from shock-heated dust in the equatorial ring (ER). From 6,000 to 8,000 days after the…
Spectro-astrometry is applied to echelle spectra of the young intermediate mass star T CrA. The aim is to better understand the origin of the [O I] and [S II] emission from T CrA and further explore the usefulness of spectro-astrometry to…
We present a neural network autoencoder structure that is able to extract essential latent spectral features from observed spectra and then reconstruct a spectrum from those features. Because of the training with a set of unpeculiar…
We study the runaway mass loss process of major eruptions of luminous blue variables (LBVs) stars, such as the 1837-1856 Great Eruption of Eta Carinae. We follow the evolution of a massive star with a spherical stellar evolution numerical…
We present multi-epoch photometry and spectroscopy of a light echo from eta Carinae's 19th century Great Eruption. This echo shows a steady decline over a decade, sampling the 1850s plateau of the eruption. Spectra show the bulk outflow…