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In this study, an image-assisted Approximate Bayesian Computation (ABC) parameter inverse method is proposed to identify the design parameters. In the proposed method, the images are mapped to a low-dimensional latent space by Variational…

Image and Video Processing · Electrical Eng. & Systems 2019-07-09 Jiaquan Wang , Yang Zeng , Xinchao Jiang , Hu Wang , Enying Li , Guangyao Li

We present high resolution (R=50,000) spectra at 2.2 um of 16 young stars in the rho Ophiuchi dark cloud. Photospheric features are detected in the spectra of 11 of these sources, all Class II young stellar objects. In 10 of these sources,…

Astrophysics · Physics 2009-11-10 G. W. Doppmann , D. T. Jaffe , R. J. White

With the construction of the VLTI (Very Large Telescope Interferometer of the European Observatory ESO for the southern hemisphere) it is now possible to make observations with resolutions of the order of milli-arc-seconds, especially in IR…

Solar and Stellar Astrophysics · Physics 2017-09-22 M. Hadjara

Aims. We attempt to determine if a dependency on spectral subtype or vsini exists for stars undergoing phase-changes between B and Be states, as well as for those stars exhibiting variability in H{\alpha} emission. Methods. We analyse the…

Solar and Stellar Astrophysics · Physics 2015-06-15 R. M. Barnsley , I. A. Steele

The SEparator for CApture Reactions (SECAR) is a next-generation recoil separator system at the Facility for Rare Isotope Beams (FRIB) designed for the direct measurement of capture reactions on unstable nuclei in inverse kinematics. To…

Exploring the possibility that fundamental constants of Nature might vary temporally or spatially constitutes one of the key science drivers for the European Southern Observatory's ESPRESSO spectrograph on the VLT and for the HIRES…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-21 Chung-Chi Lee , John K. Webb , R. F. Carswell , Dinko Milaković

Precise radial velocity measurements (delta v/c ~ 10^{-7}) of FeII lines in damped Ly-alpha systems from very high quality VLT/UVES spectra of quasars HE0515-4414 and Q1101-264 are used to probe cosmological time dependence of the fine…

This note presents a rigorous introduction to a selection of distributions along with their Fourier transforms, which are commonly encountered in signal processing and, in particular, magnetic resonance imaging (MRI). In contrast to many…

Functional Analysis · Mathematics 2025-06-24 Kaibo Tang

We report on the detection of pulsations of three pulsating subdwarf B stars observed by the TESS satellite and our results of mode identification in these stars based on an asymptotic period relation. SB 459 (TIC 067584818), SB 815 (TIC…

Aims. The derivation of spectroscopic parameters for M dwarf stars is very important in the fields of stellar and exoplanet characterization. The goal of this work is the creation of an automatic computational tool, able to derive quickly…

Solar and Stellar Astrophysics · Physics 2020-04-08 A. Antoniadis-Karnavas , S. G. Sousa , E. Delgado-Mena , N. C. Santos , G. D. C. Teixeira , V. Neves

We report a thorough investigation into the absorptive and dispersive properties of hot caesium vapour, culminating in the development of a simple analytical model for off-resonant Faraday rotation. The model, applicable to all hot alkali…

Atomic Physics · Physics 2015-05-28 Stefan L Kemp , Ifan G Hughes , Simon L Cornish

The Bayesian gravitational shear estimation algorithm developed by Bernstein and Armstrong (2014) can potentially be used to overcome multiplicative noise bias and recover shear using very low signal-to-noise ratio (S/N) galaxy images. In…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Erin S. Sheldon

Molecular FeH provides a large number of sharp and isolated absorption lines that can be used to measure radial velocity, rotation, or magnetic field strength with high accuracy. Our aim is to provide an FeH atlas for M-type stars in the…

Solar and Stellar Astrophysics · Physics 2015-05-19 S. Wende , A. Reiners , A. Seifahrt , P. F. Bernath

The imaging spectro-polarimeter VTF (Visible Tunable Filter) will be operated at the Daniel K. Inouye Solar Telescope (DKIST). Due to its capability of resolving dynamic fine structure of smaller than 0.05'', the finite acquisition time of…

Solar and Stellar Astrophysics · Physics 2023-01-18 Rolf Schlichenmaier , Daniel Pitters , Juan Manuel Borrero , Matthias Schubert

Highly-resolution optical spectra of the optical component of the IR-source IRAS01005+7910 are used to determine the spectral type of its central star, B1.5$ \pm $0.3, identify the spectral features, and analyze their profile and radial…

Solar and Stellar Astrophysics · Physics 2015-06-23 V. G. Klochkova , E. L. Chentsov , V. E. Panchuk , E. G. Sendzikas , M. V. Yushkin

We propose a Gauss-Legendre quadrature based sampling on the rotation group for the representation of a band-limited signal such that the Fourier transform (FT) of a signal can be exactly computed from its samples. Our figure of merit is…

Information Theory · Computer Science 2017-11-27 Zubair Khalid , Salman Durrani , Rodney A. Kennedy , Yves Wiaux , Jason D. McEwen

In this paper modified variants of the sparse Fourier transform algorithms from [14] are presented which improve on the approximation error bounds of the original algorithms. In addition, simple methods for extending the improved sparse…

Numerical Analysis · Mathematics 2010-10-04 M. A. Iwen

The power of asteroseismology relies on the ability to infer the stellar structure from the unambiguous frequency identification of the corresponding pulsation mode. Hence, the use of a Fourier transform is in the basis of asteroseismic…

Solar and Stellar Astrophysics · Physics 2015-07-29 J. Pascual-Granado , R. Garrido , J. C. Suárez

Aims. The X-shooter archive of several thousand telluric star spectra was skimmed for Be and Be-shell stars to derive the stellar fundamental parameters and statistical properties, in particular for the less investigated late type Be stars,…

Accurate Fourier-transform spectroscopic absorption measurements of vacuum ultraviolet transitions in atomic nitrogen and carbon were performed at the Soleil synchrotron. For $^{14}$N transitions from the $2s^22p^3\,^4$S$_{3/2}$ ground…

Atomic Physics · Physics 2020-09-04 K. -F. Lai , W. Ubachs , N. de Oliveira , E. J. Salumbides