scholarly journals The metallicity effect on line-depth ratios in APOGEE H-band spectra

2019 ◽  
Vol 485 (1) ◽  
pp. 1310-1319 ◽  
Author(s):  
Mingjie Jian ◽  
Noriyuki Matsunaga ◽  
Kei Fukue
Keyword(s):  
On Line ◽  
Band Spectra ◽  
Line Depth

scholarly journals The effect of surface gravity on line-depth ratios in the wavelength range 0.97–1.32 µm

2020 ◽  
Vol 494 (2) ◽  
pp. 1724-1734
Author(s):  
Mingjie Jian ◽  
Daisuke Taniguchi ◽  
Noriyuki Matsunaga ◽  
Naoto Kobayashi ◽  
Yuji Ikeda ◽  
...  
Keyword(s):  
Spectral Lines ◽  
Surface Gravity ◽  
Line Pair ◽  
On Line ◽  
Optical Wavelengths ◽  
The Difference ◽  
Band Spectra ◽  
Parameter Ranges ◽  
Line Depth ◽  
Effect Of Surface

ABSTRACT A line-depth ratio (LDR) of two spectral lines with different excitation potentials is expected to be correlated with the effective temperature (Teff). It is possible to determine Teff of a star with a precision of tens of Kelvin if dozens or hundreds of tight LDR–Teff relations can be used. Most of the previous studies on the LDR method were limited to optical wavelengths, but Taniguchi and collaborators reported 81 LDR relations in the YJ band, 0.97–1.32 µm, in 2018. However, with their sample of only 10 giants, it was impossible to account for the effects of surface gravity and metallicity on the LDRs well. Here, we investigate the gravity effect based on YJ-band spectra of 63 stars including dwarfs, giants, and supergiants observed with the WINERED spectrograph. We found that some LDR–Teff relations show clear offsets between the sequence of dwarfs and those of giants/supergiants. The difference between the ionization potentials of the elements considered in each line pair and the corresponding difference in the depths can, at least partly, explain the dependency of the LDR on the surface gravity. In order to expand the stellar parameter ranges that the LDR method can cover with high precision, we obtained new sets of LDR–Teff relations for solar-metal G0–K4 dwarfs and F7–K5 supergiants, respectively. The typical precision that can be achieved with our relations is 10–30 K for both dwarfs and supergiants.

scholarly journals Average Variations of Photospheric FeI and FeII Line Parameters as Function of the Magnetic Filling Factor

1990 ◽  
Vol 138 ◽  
pp. 41-46
Author(s):  
P.N. Brandt ◽  
M. Steinegger
Keyword(s):  
Filling Factor ◽  
Line Strength ◽  
Blue Shift ◽  
Disk Center ◽  
Flux Tubes ◽  
On Line ◽  
Fourier Transform Spectra ◽  
Similar Depth ◽  
Line Depth ◽  
The Continuum

A series of 17 Fourier transform spectra taken at the McMath telescope near disk center in regions of different magnetic field strengths were analyzed. Applying a multi-variate regression analysis magnetic filling factors 0 < α ≥ 0.11 were determined. With α increasing from 0 to 0.11, line bisectors averaged over groups of lines of similar depth are found to show a blue shift decreasing from 0.35 km s–1 to nearly 0.1 km s–1, when referred to the MgI line λ5172.7å. The bisectors of FeII lines exhibit smaller blue shifts than FeI lines. The increase of bisector red shift near the continuum with increasing α, found earlier by Brandt and Solanki (1987), was confirmed and is tentatively interpreted as a manifestation of downdrafts in the vicinity of flux tubes (Deinzer et al., 1984).A significant increase of line width (typically between 3 and 8%, depending on line strength) and a decrease of line depth is found with increasing filling factor. For strong lines the equivalent width W shows no variation or a slight increase, while for the weaker lines a reduction of W between a few % and > 10% is found.

scholarly journals A Comparison of Multiscale Permutation Entropy Measures in On-Line Depth of Anesthesia Monitoring

PLoS ONE ◽  
2016 ◽  
Vol 11 (10) ◽  
pp. e0164104 ◽  
Author(s):  
Cui Su ◽  
Zhenhu Liang ◽  
Xiaoli Li ◽  
Duan Li ◽  
Yongwang Li ◽  
...  
Keyword(s):  
Permutation Entropy ◽  
Depth Of Anesthesia ◽  
Entropy Measures ◽  
Anesthesia Monitoring ◽  
On Line ◽  
Line Depth

LINE-DEPTH RATIOS INH-BAND SPECTRA TO DETERMINE EFFECTIVE TEMPERATURES OF G- AND K-TYPE GIANTS AND SUPERGIANTS

2015 ◽  
Vol 812 (1) ◽  
pp. 64 ◽  
Author(s):  
Kei Fukue ◽  
Noriyuki Matsunaga ◽  
Ryo Yamamoto ◽  
Sohei Kondo ◽  
Naoto Kobayashi ◽  
...  
Keyword(s):  
Effective Temperatures ◽  
Band Spectra ◽  
Line Depth

On-line depth measurement for laser-drilled holes based on the intensity of plasma emission

2014 ◽  
Vol 25 (9) ◽  
pp. 094007 ◽  
Author(s):  
Chao-Ching Ho ◽  
Chih-Mu Chiu ◽  
Yuan-Jen Chang ◽  
Jin-Chen Hsu ◽  
Chia-Lung Kuo
Keyword(s):  
Plasma Emission ◽  
Depth Measurement ◽  
On Line ◽  
Line Depth

Accurate on-line depth calibration with a laser interferometer during SIMS profiling on the Cameca IMS WF instrument

2004 ◽  
Vol 231-232 ◽  
pp. 954-958 ◽  
Author(s):  
A. Merkulov ◽  
O. Merkulova ◽  
E. de Chambost ◽  
M. Schuhmacher
Keyword(s):  
Laser Interferometer ◽  
On Line ◽  
Line Depth

scholarly journals RASSINE: Interactive tool for normalising stellar spectra

2020 ◽  
Vol 640 ◽  
pp. A42 ◽  
Author(s):  
M. Cretignier ◽  
J. Francfort ◽  
X. Dumusque ◽  
R. Allart ◽  
F. Pepe
Keyword(s):  
Spectral Lines ◽  
Parameter Determination ◽  
Polynomial Fitting ◽  
Stellar Spectra ◽  
Photon Noise ◽  
Graphical Feedback ◽  
Noise Limit ◽  
On Line ◽  
Band Absorption ◽  
Line Depth

Aims. We provide an open-source code allowing an easy, intuitive, and robust normalisation of spectra. Methods. We developed RASSINE, a Python code for normalising merged 1D spectra through the concepts of convex hulls. The code uses six parameters that can be easily fine-tuned. The code also provides a complete user-friendly interactive interface, including graphical feedback, that helps the user to choose the parameters as easily as possible. To facilitate the normalisation even further, RASSINE can provide a first guess for the parameters that are derived directly from the merged 1D spectrum based on previously performed calibrations. Results. For HARPS spectra of the Sun that were obtained with the HELIOS solar telescope, a continuum accuracy of 0.20% on line depth can be reached after normalisation with RASSINE. This is three times better than with the commonly used method of polynomial fitting. For HARPS spectra of α Cen B, a continuum accuracy of 2.0% is reached. This rather poor accuracy is mainly due to molecular band absorption and the high density of spectral lines in the bluest part of the merged 1D spectrum. When wavelengths shorter than 4500 Å are excluded, the continuum accuracy improves by up to 1.2%. The line-depth precision on individual spectrum normalisation is estimated to be ∼0.15%, which can be reduced to the photon-noise limit (0.10%) when a time series of spectra is given as input for RASSINE. Conclusions. With a continuum accuracy higher than the polynomial fitting method and a line-depth precision compatible with photon noise, RASSINE is a tool that can find applications in numerous cases, for example stellar parameter determination, transmission spectroscopy of exoplanet atmospheres, or activity-sensitive line detection.

The on-line use of histogram data for high-speed correction and alignment of electron microscope images

1984 ◽  
Vol 42 ◽  
pp. 556-557
Author(s):  
William Krakow
Keyword(s):  
Power Spectrum ◽  
High Speed ◽  
Direct Memory Access ◽  
Digital Television ◽  
Contrast Transfer Function ◽  
The Past ◽  
High Resolution Tem ◽  
On Line ◽  
Correction Of Astigmatism ◽  
The Fourier Transform

In the past few years on-line digital television frame store devices coupled to computers have been employed to attempt to measure the microscope parameters of defocus and astigmatism. The ultimate goal of such tasks is to fully adjust the operating parameters of the microscope and obtain an optimum image for viewing in terms of its information content. The initial approach to this problem, for high resolution TEM imaging, was to obtain the power spectrum from the Fourier transform of an image, find the contrast transfer function oscillation maxima, and subsequently correct the image. This technique requires a fast computer, a direct memory access device and even an array processor to accomplish these tasks on limited size arrays in a few seconds per image. It is not clear that the power spectrum could be used for more than defocus correction since the correction of astigmatism is a formidable problem of pattern recognition.

Image registration with a computer driven S.T.E.M.

1978 ◽  
Vol 36 (1) ◽  
pp. 98-99
Author(s):  
A.M.H. Schepman ◽  
J.A.P. van der Voort ◽  
J.E. Mellema
Keyword(s):  
Spot Size ◽  
Scanning Transmission Electron Microscope ◽  
Small Computer ◽  
Structural Studies ◽  
Area Of Interest ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Specimen Area ◽  
On Line ◽  
Minimum Distances

A Scanning Transmission Electron Microscope (STEM) was coupled to a small computer. The system (see Fig. 1) has been built using a Philips EM400, equipped with a scanning attachment and a DEC PDP11/34 computer with 34K memory. The gun (Fig. 2) consists of a continuously renewed tip of radius 0.2 to 0.4 μm of a tungsten wire heated just below its melting point by a focussed laser beam (1). On-line operation procedures were developped aiming at the reduction of the amount of radiation of the specimen area of interest, while selecting the various imaging parameters and upon registration of the information content. Whereas the theoretical limiting spot size is 0.75 nm (2), routine resolution checks showed minimum distances in the order 1.2 to 1.5 nm between corresponding intensity maxima in successive scans. This value is sufficient for structural studies of regular biological material to test the performance of STEM over high resolution CTEM.

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