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In Data Release 9 of LAMOST, we present measurements of v sin i for a total of 121,698 stars measured using the Medium Resolution Spectrograph (MRS) and 80,108 stars using the Low Resolution Spectrograph (LRS). These values were obtained…

Solar and Stellar Astrophysics · Physics 2024-01-09 Fang Zuo , A-Li Luo , Bing Du , Yinbi Li , Hugh R. A. Jones , Yi-han Song , Xiao Kong , Yan-xin Guo

A method is developed for fitting theoretically predicted astronomical spectra to an observed spectrum. Using a hierarchical Bayesian principle, the method takes both systematic and statistical measurement errors into account, which has not…

Astrophysics · Physics 2008-11-26 Z. Shkedy , L. Decin , G. Molenberghs , C. Aerts

The rapidly rotating Be star phi Persei was spun up by mass and angular momentum transfer from a now stripped-down, hot subdwarf companion. Here we present the first high angular resolution images of phi Persei made possible by new…

[abridged] Inversion techniques are the most powerful methods to obtain information about the thermodynamical and magnetic properties of solar and stellar atmospheres. In the last years, we have witnessed the development of highly…

Astrophysics · Physics 2009-11-13 A. Asensio Ramos , M. J. Martinez Gonzalez , J. A. Rubino-Martin

We analyse medium-resolution spectra (R\sim 18000) of 19 late type dwarfs in order to determine vsini-s using synthetic rather than observational template spectra. For this purpose observational data around 2.2 $\mu$m of stars with spectral…

Solar and Stellar Astrophysics · Physics 2015-06-04 Yu. Lyubchik , H. R. A. Jones , Ya. V. Pavlenko , D. J. Pinfield , K. R. Covey

We test the viability of training machine learning algorithms with synthetic H alpha line profiles to determine the inclination angles of Be stars (the angle between the central B star's rotation axis and the observer's line of sight) from…

Solar and Stellar Astrophysics · Physics 2023-10-31 B. D. Lailey , T. A. A. Sigut

It is possible to learn about the orientation of a star's rotation axis by combining measurements of the star's rotation velocity ($v$) and its projection onto our line of sight ($v\sin i$). This idea has found many applications, including…

Instrumentation and Methods for Astrophysics · Physics 2020-02-19 Kento Masuda , Joshua N. Winn

We develop a new method to determine oscillator strength values of atomic absorption lines with state-of-the-art detailed spectral synthesis calculations of the optical spectrum of the Sun and of standard spectral reference stars. We update…

Solar and Stellar Astrophysics · Physics 2015-05-20 A. Lobel

In this paper we propose a new fast Fourier transform to recover a real nonnegative signal ${\bf x}$ from its discrete Fourier transform. If the signal ${\mathbf x}$ appears to have a short support, i.e., vanishes outside a support interval…

Numerical Analysis · Mathematics 2020-02-19 Gerlind Plonka , Katrin Wannenwetsch

The convolution potential arises in a wide variety of application areas, and its efficient and accurate evaluation encounters three challenges: singularity, nonlocality and anisotropy. We introduce a fast algorithm based on a far-field…

Numerical Analysis · Mathematics 2025-04-29 Xin Liu , Yong Zhang

High-dispersion IUE data encode significant information about aggregate line absorptions that cannot be conveniently extracted from individual spectra. We apply a new technique in which fluxes from each echelle order of a short wavelength…

Astrophysics · Physics 2009-11-06 Myron A. Smith

Galaxy profile fitting is a ubiquitous technique that provides the backbone for photometric and morphological measurements in modern extragalactic surveys. A recent innovation in profile fitting algorithms is to render, or create, the model…

Instrumentation and Methods for Astrophysics · Physics 2026-04-17 Tim B. Miller , Imad Pasha

Fourier single-pixel imaging (FSI) is a data-efficient single-pixel imaging (SPI). However, there is still a serious challenge to obtain higher imaging quality using fewer measurements, which limits the development of real-time SPI. In this…

Image and Video Processing · Electrical Eng. & Systems 2023-11-07 Huan Cui , Jie Cao , Qun Hao , Haoyu Zhang , Chang Zhou

Classification of young stellar objects (YSOs) into different evolutionary stages helps us to understand the formation process of new stars and planetary systems. Such classification has traditionally been based on spectral energy…

Astrophysics of Galaxies · Physics 2018-09-05 Oskari Miettinen

We conduct a systematic study on the effects of rapid rotation on predicted Be star observables. We use the three-dimensional Monte Carlo radiative transfer code, \textsc{hdust}, to model a comprehensive range of Be star subtypes at varying…

We have developed a new three-dimensional algorithm, based on the standard P$^3$M method, for computing deflections due to weak gravitational lensing. We compare the results of this method with those of the two-dimensional planar approach,…

Astrophysics · Physics 2009-10-31 H. M. P. Couchman , Andrew J. Barber , Peter A. Thomas

Spectral analysis is a powerful tool to investigate stellar properties and it has been widely used for decades now. However, the methods considered to perform this kind of analysis are mostly based on iteration among a few diagnostic lines…

Instrumentation and Methods for Astrophysics · Physics 2015-09-30 J-M. Mugnes , C. Robert

We present $V$-band photometry of the 20,000 brightest asteroids using data from the All-Sky Automated Survey for Supernovae (ASAS-SN) between 2012 and 2018. We were able to apply the convex inversion method to more than 5,000 asteroids…

Earth and Planetary Astrophysics · Physics 2021-10-13 J. Hanuš , O. Pejcha , B. J. Shappee , C. S. Kochanek , K. Z. Stanek , T. W. -S. Holoien

We present a moderate-resolution (~20 km/s) spectrum of the mini broad-absorption-line QSO PG1351+64 between 915-1180 A, obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE). Additional spectra at longer wavelengths were also…

We demonstrate a means of detecting weak optical transitions in cold atoms that undergo cyclic routines with high sensitivity. The gain in sensitivity is made by probing atoms on alternate cycles leading to a regular modulation of the…

Atomic Physics · Physics 2021-01-08 Jesse S. Schelfhout , Lilani D. Toms-Hardman , John J. McFerran