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Multi-object or integral field spectrographs are recognized techniques for achieving simultaneous spectroscopic observations of different or extended sky objects with a high multiplex factor. In this communication is described a…

Instrumentation and Detectors · Physics 2016-12-14 Francois Henault , Florence Laurent

A comparison of the most popular techniques for 3D spectroscopy is presented in a way which should hopefully be useful for astronomers intending to use these techniques. Integral field spectroscopy, slitless spectroscopy, tunable imaging…

Astrophysics · Physics 2007-05-23 Sperello di Serego Alighieri

A new method for the classification of respiratory diseases is presented. The method is based on a novel class of features, extracted from pulmonary sounds, by parameterizing their spectrograms that are represented as surfaces, and by…

Signal Processing · Electrical Eng. & Systems 2021-06-07 Jeremy Levy , Alexander Naitsat , Yehoshua Y. Zeevi

We present a semi-empirical spectral classification scheme for normal B-type stars using near-infrared spectra (1.5-1.7 $\mu$m) from the SDSS APOGEE2-N DR14 database. The main motivation for working with B-type stars is their importance in…

Hyperspectral imaging aims at providing information on both the spatial and the spectral distribution of light, with high resolution. However, state-of-the-art protocols are characterized by an intrinsic trade-off imposing to sacrifice…

Optics · Physics 2024-07-22 Gianlorenzo Massaro , Francesco V. Pepe , Milena D'Angelo

We present a method for automated classification of galaxies with low signal-to-noise (S/N) spectra typical of redshift surveys. We develop spectral simulations based on the parameters for the 2dF Galaxy Redshift Survey, and with these…

Astrophysics · Physics 2015-06-24 S. R. Folkes , O. Lahav , S. J. Maddox

In this technical note, we deal with a spectrum approximation problem arising in THREE-like multivariate spectral estimation approaches. The solution to the problem minimizes a suitable divergence index with respect to an a priori spectral…

Optimization and Control · Mathematics 2014-06-27 Mattia Zorzi

The zeros of the spectrogram have proven to be a relevant feature to describe the time-frequency structure of a signal, originated by the destructive interference between components in the time-frequency plane. In this work, a…

Signal Processing · Electrical Eng. & Systems 2022-10-12 Juan M. Miramont , François Auger , Marcelo A. Colominas , Nils Laurent , Sylvain Meignen

One of the possible variants of the classification of trigonometric interpolation splines is considered, depending on the chosen convergence factors, the distribution of signs of the basis functions and the interpolation factors. The…

Numerical Analysis · Mathematics 2019-10-03 V. P. Denysiuk

The combination of photometry, spectroscopy and spectropolarimetry of the chemically peculiar stars often aims to study the complex physical phenomena such as stellar pulsation, chemical inhomogeneity, magnetic field and their interplay…

Solar and Stellar Astrophysics · Physics 2017-01-25 Santosh Joshi , Eugene Semenko , A. Moiseeva , Kaushal Sharma , Y. C. Joshi , M. Sachkov , Harinder P. Singh , Yerra Bharat Kumar

In the past years we have made great efforts to reduce the statistical and systematic uncertainties in stellar parameter and chemical abundance determinations of early B-type stars. Both the construction of robust model atoms for non-LTE…

Solar and Stellar Astrophysics · Physics 2009-02-18 Maria-Fernanda Nieva , Norbert Przybilla

Multilayer networks represent systems in which there are several topological levels each one representing one kind of interaction or interdependency between the systems' elements. These networks have attracted a lot of attention recently…

Physics and Society · Physics 2015-04-22 Emanuele Cozzo , Guilherme Ferraz de Arruda , Francisco A. Rodrigues , Yamir Moreno

Although rare, massive stars, being the main sources of ionizing radiation, chemical enrichment and mechanical energy in the Galaxy, are the most important objects of the stellar population. This review presents the many different aspects…

Astrophysics · Physics 2007-05-23 Yael Naze

Spectral clustering is a fast and popular algorithm for finding clusters in networks. Recently, Chaudhuri et al. (2012) and Amini et al.(2012) proposed inspired variations on the algorithm that artificially inflate the node degrees for…

Machine Learning · Statistics 2013-09-18 Tai Qin , Karl Rohe

We describe a simple step-by-step guide to qualitative interpretation of galaxy spectra. Rather than an alternative to existing automated tools, it is put forward as an instrument for quick-look analysis, and for gaining physical insight…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 J. Sanchez Almeida , R. Terlevich , E. Terlevich , R. Cid Fernandes , A. B. Morales-Luis

Motivation: Tumor classification using Imaging Mass Spectrometry (IMS) data has a high potential for future applications in pathology. Due to the complexity and size of the data, automated feature extraction and classification steps are…

Machine Learning · Statistics 2018-06-28 Jens Behrmann , Christian Etmann , Tobias Boskamp , Rita Casadonte , Jörg Kriegsmann , Peter Maass

We review a range of stastistical methods for analyzing the structures of star clusters, and derive a new measure ${\cal Q}$ which both quantifies, and distinguishes between, a (relatively smooth) large-scale radial density gradient and…

Astrophysics · Physics 2009-11-10 Annabel Cartwright , Anthony P Whitworth

To date, Galactic Astronomy has largely concerned itself with astrophysical processes, and with the locations, space motions and compositions of objects. Consider, for example, the elucidation of the components of the Galaxy over the past…

The wide application of estimation techniques in system analysis enable us to best determine and understand the history of system states. This paper attempts to delineate the theory behind linear and non-linear estimation with a suitable…

Applications · Statistics 2014-10-21 Raja Manish

Libraries of stellar spectra find many uses in astrophysics, from photometric calibration to stellar population synthesis. We present low resolution spectra of 40 stars from 0.2 micrometers (ultraviolet) to 1.0 micrometers (near infrared)…

Solar and Stellar Astrophysics · Physics 2018-07-25 Islam Khan , Guy Worthey