A comparison of near-infrared spectra of the galactic center compact He I emission-line sources and early-type mass-losing stars

1995 ◽  
Vol 441 ◽  
pp. 603 ◽  
Author(s):  
R. D. Blum ◽  
D. L. Depoy ◽  
K. Sellgren
Keyword(s):  
Emission Line ◽  
Infrared Spectra ◽  
Near Infrared ◽  
Galactic Center ◽  
Early Type ◽  
Near Infrared Spectra ◽  
Type Mass

scholarly journals A Comparison of Near Infrared Spectra of the Galactic Center He I Emission Line Sources and Early Type Mass Losing Stars

1996 ◽  
Vol 169 ◽  
pp. 225-230
Author(s):  
R. D. Blum ◽  
D. L. Depoy ◽  
K. Sellgren
Keyword(s):  
Emission Line ◽  
Infrared Spectra ◽  
Near Infrared ◽  
Galactic Center ◽  
Early Type ◽  
Near Infrared Spectra ◽  
Wide Range ◽  
Comparison Stars ◽  
Band Spectra ◽  
Type Mass

We have obtained R ≈ 570 resolution K band spectra of eight sources in the Galactic Center, including four sources within the IRS 16 cluster, IRS 13, IRS 1W, and the compact He I emission line sources AF (also known as AHH) and AHH NW. We have also obtained R ≈ 570 H and K band spectra of nine galactic and LMC early–type mass–losing stars, including Ofpe/WN9 and WN stars. The spectra of both the Galactic Center sources and the comparison stars show a wide range of behavior in the He I (1.70 μm, 2.06 μm, 2.11 μm) and H I (Brackett series) lines. We find significantly larger He I equivalent widths in the AF source and two galactic early type mass losing stars than in any of the LMC stars. Several of the Galactic Center He I sources are found to have higher He I velocity widths than any of the galactic or LMC early type mass losing stars. At least one source, IRS 13, shows a strong red wing to the He I 2.06 μm emission.

scholarly journals Near Infrared Spectroscopic Observations of Early-type Be Stars

2000 ◽  
Vol 175 ◽  
pp. 468-471 ◽  
Author(s):  
N. M. Ashok ◽  
D. P. K. Banerjee
Keyword(s):  
Emission Line ◽  
Infrared Spectra ◽  
Near Infrared ◽  
Be Stars ◽  
Early Type ◽  
Line Flux ◽  
Near Infrared Spectra ◽  
Medium Resolution ◽  
Significant Strength ◽  
Lower Temperature

AbstractThe medium resolution (R=1000) near infrared spectra of 30 early type Be stars obtained during the period October 1998-April 1999 are presented. The Paschen β and Brackett γ lines are seen in emission in majority of these stars. The higher order Brackett series lines from m=10 to 19 are detected in emission with significant strength compared to the Brackett γ emission line flux indicating the effect of optical depth. The Fe II line at 1.6873μm is detected in a small number of stars indicating existence of higher density and lower temperature emission zone.

Near-infrared spectra of compact stellar wind sources at the Galactic center

1995 ◽  
Vol 439 ◽  
pp. 202 ◽  
Author(s):  
S. Libonate ◽  
J. L. Pipher ◽  
W. J. Forrest ◽  
M. L. N. Ashby
Keyword(s):  
Infrared Spectra ◽  
Stellar Wind ◽  
Near Infrared ◽  
Galactic Center ◽  
Near Infrared Spectra

scholarly journals Emission Lines in the Near-infrared Spectra of the Infrared Quintuplet Stars in the Galactic Center

2017 ◽  
Vol 845 (2) ◽  
pp. 127 ◽  
Author(s):  
F. Najarro ◽  
T. R. Geballe ◽  
D. F. Figer ◽  
D. de la Fuente
Keyword(s):  
Infrared Spectra ◽  
Near Infrared ◽  
Galactic Center ◽  
Emission Lines ◽  
Near Infrared Spectra

scholarly journals The Origin of Weak Emission-Line AGNs

2012 ◽  
Vol 8 (S290) ◽  
pp. 267-268
Author(s):  
Yuan Liu ◽  
Jin Zhang ◽  
Shuang-Nan Zhang
Keyword(s):  
Emission Line ◽  
Optical Spectroscopy ◽  
Infrared Spectra ◽  
Near Infrared ◽  
Early Stage ◽  
Optical Emission ◽  
Emission Lines ◽  
Near Infrared Spectra

AbstractSome abnormal AGNs are discovered in the SDSS data recently. The usual UV/optical emission lines are exceptionally weak in their UV/optical spectroscopy, though the shapes and luminosities of their continua are comparable with that of the normal AGNs. We investigated the optical variations and the near-infrared spectra of these weak emission-line AGNs. We propose that these AGNs can be interpreted as the early stage of an active cycle of AGNs.

Rapid Determining Contents of the Rhubarb Anthraquinones Compounds by Support Vector Machines Modeling based on Near Infrared Spectra

2020 ◽  
Vol 16 ◽  
Author(s):  
Linqi Liu ◽  
JInhua Luo ◽  
Chenxi Zhao ◽  
Bingxue Zhang ◽  
Wei Fan ◽  
...  
Keyword(s):  
Infrared Spectra ◽  
Near Infrared ◽  
Mean Squared Error ◽  
Rapid Determination ◽  
Partial Least Square ◽  
Least Square ◽  
Support Vector ◽  
Near Infrared Spectra ◽  
Aloe Emodin ◽  
Relative Differences

BACKGROUND: Measuring medicinal compounds to evaluate their quality and efficacy has been recognized as a useful approach in treatment. Rhubarb anthraquinones compounds (mainly including aloe-emodin, rhein, emodin, chrysophanol and physcion) are its main effective components as purgating drug. In the current Chinese Pharmacopoeia, the total anthraquinones content is designated as its quantitative quality and control index while the content of each compound has not been specified. METHODS: On the basis of forty rhubarb samples, the correlation models between the near infrared spectra and UPLC analysis data were constructed using support vector machine (SVM) and partial least square (PLS) methods according to Kennard and Stone algorithm for dividing the calibration/prediction datasets. Good models mean they have high correlation coefficients (R2) and low root mean squared error of prediction (RMSEP) values. RESULTS: The models constructed by SVM have much better performance than those by PLS methods. The SVM models have high R2 of 0.8951, 0.9738, 0.9849, 0.9779, 0.9411 and 0.9862 that correspond to aloe-emodin, rhein, emodin, chrysophanol, physcion and total anthraquinones contents, respectively. The corresponding RMSEPs are 0.3592, 0.4182, 0.4508, 0.7121, 0.8365 and 1.7910, respectively. 75% of the predicted results have relative differences being lower than 10%. As for rhein and total anthraquinones, all of the predicted results have relative differences being lower than 10%. CONCLUSION: The nonlinear models constructed by SVM showed good performances with predicted values close to the experimental values. This can perform the rapid determination of the main medicinal ingredients in rhubarb medicinal materials.

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