Some problems of objective-prism spectra classification

1966 ◽  
Vol 24 ◽  
pp. 51-52
Author(s):  
E. K. Kharadze ◽  
R. A. Bartaya
Keyword(s):  
Short Wave ◽  
High Quality ◽  
Stellar Spectra ◽  
Objective Prism

The unique 70-cm meniscus-type telescope of the Abastumani Astrophysical Observatory supplied with two objective prisms and the seeing conditions characteristic at Mount Kanobili (Abastumani) permit us to obtain stellar spectra of a high quality. No additional design to improve the “climate” immediately around the telescope itself is being applied. The dispersions and photographic magnitude limits are 160 and 660Å/mm, and 12–13, respectively. The short-wave end of spectra reaches 3500–3400Å.

scholarly journals The SeaSWIR dataset

2018 ◽  
Author(s):  
Els Knaeps ◽  
David Doxaran ◽  
Ana Dogliotti ◽  
Bouchra Nechad ◽  
Kevin Ruddick ◽  
...  
Keyword(s):  
Quality Control ◽  
Suspended Matter ◽  
Short Wave ◽  
Total Suspended Matter ◽  
High Quality ◽  
Detailed Measurement ◽  
La Plata ◽  
Measurement Protocol ◽  
Wide Range ◽  
Quality Measurements

Abstract. The SeaSWIR dataset consists of 137 ASD (Analytical Spectral Devices, Inc.) marine reflectances, 137 Total Suspended Matter (TSM) measurements and 97 turbidity measurements gathered at three turbid estuarine sites (Gironde, La Plata, Scheldt). The dataset is valuable because of the high quality measurements of the marine reflectance in the Short Wave InfraRed I region (SWIR-I: 1000–1200 nm) and SWIR-II (1200–1300 nm) and because of the wide range of TSM concentrations from 48 mg L−1 up to 1400 mg L−1. The ASD measurements were gathered using a detailed measurement protocol and were subjected to a strict quality control. The SeaSWIR marine reflectance is characterized by low reflectance at short wavelengths (

scholarly journals The Belgian Repository of fundamental Atomic data and Stellar Spectra (BRASS)

2019 ◽  
Vol 15 (S350) ◽  
pp. 386-387
Author(s):  
M. Laverick ◽  
A. Lobel ◽  
P. Royer ◽  
T. Merle ◽  
C. Martayan ◽  
...  
Keyword(s):  
Quality Assessment ◽  
State Of The Art ◽  
Oscillator Strengths ◽  
Atomic Data ◽  
Synthetic Spectrum ◽  
High Quality ◽  
Data Repositories ◽  
Stellar Spectra ◽  
Atomic Transitions ◽  
Stellar Spectroscopy

AbstractThe Belgian Repository of fundamental Atomic data and Stellar Spectra (BRASS) aims to provide one of the largest systematic and homogeneous quality assessment to date of literature atomic data required for stellar spectroscopy. By comparing state-of-the-art synthetic spectrum calculations with extremely high-quality observed benchmark spectra, we have critically evaluated fundamental atomic data, such as line wavelengths and oscillator strengths, for thousands of astrophysically-relevant transitions found in the literature and across several major atomic data repositories. These proceedings provide a short overview of the BRASS project to date, highlighting our recent efforts to investigate and quality-assess the atomic literature data pertaining to over a thousand atomic transitions present in FGK-type stellar spectra. BRASS provides all quality assessed data, theoretical spectra, and observed spectra in a new interactive database under development at brass.sdf.org.

scholarly journals Automatic extraction and classification of low-dispersion objective prism stellar spectra

2000 ◽  
Vol 142 (2) ◽  
pp. 339-345 ◽  
Author(s):  
E. Bratsolis ◽  
I. Bellas-Velidis ◽  
A. Dapergolas ◽  
E. Kontizas ◽  
M. Kontizas
Keyword(s):  
Automatic Extraction ◽  
Stellar Spectra ◽  
Objective Prism ◽  
Low Dispersion

scholarly journals MUSE library of stellar spectra

2019 ◽  
Vol 629 ◽  
pp. A100 ◽  
Author(s):  
Valentin D. Ivanov ◽  
Lodovico Coccato ◽  
Mark J. Neeser ◽  
Fernando Selman ◽  
Alessandro Pizzella ◽  
...  
Keyword(s):  
Chemical Species ◽  
High Signal ◽  
High Fidelity ◽  
Physical Processes ◽  
High Quality ◽  
Stellar Spectra ◽  
Field Unit ◽  
Spectral Libraries ◽  
Integral Field ◽  
The Continuum

Context. Empirical stellar spectral libraries have applications in both extragalactic and stellar studies, and they confer an advantage over theoretical libraries because they naturally include all relevant chemical species and physical processes. In recent years we have seen a stream of new sets of high-quality spectra, but increasing the spectral resolution and widening the wavelength coverage means resorting to multi-order echelle spectrographs. Assembling the spectra from many pieces results in lower fidelity of their shapes. Aims. We aim to offer the community a library of high-signal-to-noise spectra with reliable continuum shapes. Furthermore, the use of an integral field unit (IFU) alleviates the issue of slit losses. Methods. Our library was built with the MUSE (Multi-Unit Spectroscopic Explorer) IFU instrument. We obtained spectra over nearly the entire visual band (λ ∼ 4800–9300 Å). Results. We assembled a library of 35 high-quality MUSE spectra for a subset of the stars from the X-shooter Spectral Library. We verified the continuum shape of these spectra with synthetic broadband colors derived from the spectra. We also report some spectral indices from the Lick system, derived from the new observations. Conclusions. We offer a high-fidelity set of stellar spectra covering the Hertzsprung-Russell diagram. These can be used for both extragalactic and stellar studies and demonstrate that the IFUs are excellent tools for building reliable spectral libraries.

scholarly journals The EDIBLES survey II. The detectability of C60+ bands

2018 ◽  
Vol 614 ◽  
pp. A28 ◽  
Author(s):  
R. Lallement ◽  
N. L. J. Cox ◽  
J. Cami ◽  
J. Smoker ◽  
A. Fahrang ◽  
...  
Keyword(s):  
Gas Phase ◽  
Laboratory Experiments ◽  
Wavelength Shift ◽  
Atmospheric Conditions ◽  
Echelle Spectrograph ◽  
High Quality ◽  
Stellar Spectra ◽  
Diffuse Interstellar Bands ◽  
Infra Red ◽  
The Difference

Gas phase spectroscopic laboratory experiments for the buckminsterfullerene cation C60+ have resulted in accurate rest wavelengths for five C60+ transitions that have been compared with diffuse interstellar bands (DIBs) in the near infra-red. Detecting these in astronomical spectra is difficult because of the strong contamination of ground-based spectra by atmospheric water vapor, to the presence of weak and shallow stellar lines and/or blending with other weak DIBs. The detection of the two strong bands has been claimed by several teams, and the three additional and weaker bands have been detected in a few sources. Certain recent papers have argued against the identification of C60+ based on spectral analyses claiming (i) a large variation in the ratio of the equivalent widths of the 9632 and 9577 Å bands, (ii) a large redshift of the 9632 Å band for the Orion star HD 37022, and (iii) the non-detection of the weaker 9428 Å DIB. Here we address these three points: (i) We show that the model stellar line correction for the 9632 Å DIB overestimates the difference between the strengths of the lines in giant and dwarf star spectra, casting doubts on the conclusions about the ratio variability. (ii) Using high quality stellar spectra from the ESO Diffuse Interstellar Bands Large Exploration Survey (EDIBLES), recorded with the ESO/Paranal Ultraviolet Echelle Spectrograph (UVES) in about the same atmospheric conditions, we find no wavelength shift in the 9632 Å band toward HD 37022. (iii) Using EDIBLES spectra and data from the Echelle SpectroPolarimetric Device for the Observation of Stars (ESPaDOnS) at CFHT we show that the presence of a weak 9428 Å band cannot be ruled out, even in the same observations that a previous study claimed it was not present.

Automated detection and classification of objective prism stellar spectra

1999 ◽  
Vol 18 (3) ◽  
pp. 413-424
Author(s):  
I. Bellas-Velidis ◽  
F. Pasian ◽  
E. Kontizas ◽  
A. Dapergolas ◽  
E. Bratsolis ◽  
...  
Keyword(s):  
Automated Detection ◽  
Stellar Spectra ◽  
Objective Prism

scholarly journals Recent Developments in the Work on Automated Spectral Classification by Means of Objective Prism Spectra

1994 ◽  
Vol 161 ◽  
pp. 253-254
Author(s):  
V. Malyuto ◽  
T. Shvelidze
Keyword(s):  
Spectral Classification ◽  
Proper Motions ◽  
Stellar Spectra ◽  
Meridional Section ◽  
Spectrometric Data ◽  
Software Packages ◽  
The Galaxy ◽  
Recent Developments ◽  
Objective Prism

Some years ago a complex programme of studying the main meridional section of the Galaxy was started by astronomers of Kiev, Tartu, Abastumani and Vilnius Observatories with the aim of improving our knowledge of spatial and kinematic characteristics of stellar populations. Characteristic to the programme is the use of absolute proper motions of stars together with automated quantitative spectral classification for large stellar-statistical samples. The data are gathered in areas lying within 30° of the main meridional section of the Galaxy. To classify stars, objective prism stellar spectra of intermediate dispersion (166 å/mm at Hγ), obtained with the 70 cm meniscus telescope at the Abastumani Astrophysical Observatory, are used. The field diameter is 4° 50′, and the limiting photographical stellar magnitude is about 12 m . Our system of automated quantitative spectral classification of F-K stars applies criteria evaluation and is mainly based on two software packages: the SDR package for spectrometric data reduction and the CTATEC-2 package determining the linear regression model used for classification (Malyuto & Shvelidze 1989; Malyuto, Pelt & Shvelidze 1993).

scholarly journals The University of Texas Catalog of Ultraviolet and Optical Stellar Data

1977 ◽  
Vol 35 ◽  
pp. 93-101
Author(s):  
Sidney B. Parsons ◽  
James D. Wray
Keyword(s):  
Early Type ◽  
Previous Knowledge ◽  
Auxiliary Data ◽  
Stellar Spectra ◽  
University Of Texas ◽  
Data Files ◽  
Objective Prism ◽  
Early Type Stars ◽  
The University ◽  
Proper Analysis

At the University of Texas we are working on the reduction and analysis of ultraviolet stellar spectra obtained with the S-019 experiment on Skylab (Karl Henize, principal investigator). Our objective prism photographs recorded nearly 10,000 stars at wavelengths shortward of 3000Å, many of them of 9th or 10th visual mag., and for proper analysis we need to assemble ground-based data into a workable master catalog. The most immediate application of this catalog will be computer simulation of the ultraviolet photographs in order to point out significant anomalies with respect to previous knowledge. We need to have a catalog, then, which is as complete as possible in terms of the existence of early-type stars to at least 10th mag., their spectral types, photometry, known peculiarities, duplicity, and so forth. Also the master catalog must contain only a single value for each magnitude and for the spectral type, rather than a listing of various determinations, in order to be useful for the simulation. This means that auxiliary data files are needed for recording data in more detail so that the master catalog may be kept at a workable size, while at the same time the basic data are readily available.

scholarly journals The Belgian Repository of Fundamental Atomic Data and Stellar Spectra (BRASS) Identifying Fruitful Methods for Producing Atomic Data

Galaxies ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 78 ◽  
Author(s):  
Mike Laverick ◽  
Alex Lobel ◽  
Pierre Royer ◽  
Christophe Martayan ◽  
Thibault Merle ◽  
...  
Keyword(s):  
Quality Assessment ◽  
Atomic Physics ◽  
Spectral Synthesis ◽  
Atomic Data ◽  
High Quality ◽  
Stellar Spectra ◽  
Physics Community

The Belgian repository of fundamental atomic data and stellar spectra (BRASS) aims to provide the largest systematic and homogeneous quality assessment to-date of input atomic data required for stellar spectral synthesis. In addition to quality-assessed atomic data, BRASS shall also provide of a range of extremely high-quality benchmark stellar spectra spanning late B-type stars to early K-type stars. In this paper, we summarise the project’s progress and available results to-date. We provide a brief comparison between our results and the BRASS project’s compiled and cross-matched atomic literature, with the goal of providing useful feedback to the atomic community on which methods may produce more reliable and accurate atomic data. We hope that the examples presented here stimulate further investigation by the atomic physics community.

BRASS: Cross-match of atomic repositories and spectral line blending investigations

2017 ◽  
Vol 95 (9) ◽  
pp. 843-846 ◽  
Author(s):  
M. Laverick ◽  
A. Lobel ◽  
P. Royer ◽  
C. Martayan ◽  
T. Merle
Keyword(s):  
Spectral Line ◽  
State Of The Art ◽  
Spectral Synthesis ◽  
Atomic Data ◽  
High Quality ◽  
Stellar Spectra ◽  
Synthetic Spectra ◽  
Atomic Lines ◽  
Quality Assessments ◽  
Cross Match

The Belgian repository of fundamental atomic data and stellar spectra (BRASS) aims to critically evaluate atomic data, from publicly available repositories, by comparing state-of-the-art synthetic spectra against high-quality benchmark stellar spectra. In preparation for our assessment we have cross-matched atomic line transitions from several different databases. Our investigation revealed significant updates in log(gf) values, sometimes as large as 2–4 dex, that fully justify the need for systematic quality assessments of the atomic data. We have also investigated the spectral line blending of an initial subset of 2647 atomic lines using spectral synthesis calculations, for the spectral types BAFGK.

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