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We investigate the integrated spectra of a sample of 24 normal galaxies. A principal component analysis suggests that most of the variance present in the spectra is due to the differences in morphology of the galaxies in the sample. We show…

Astrophysics · Physics 2009-10-22 Laerte Sodre , Hector Cuevas

In this paper we examine the application of the random forest classifier for the all relevant feature selection problem. To this end we first examine two recently proposed all relevant feature selection algorithms, both being a random…

Artificial Intelligence · Computer Science 2011-06-28 Miron B. Kursa , Witold R. Rudnicki

We propose a novel methodology, forest floor, to visualize and interpret random forest (RF) models. RF is a popular and useful tool for non-linear multi-variate classification and regression, which yields a good trade-off between robustness…

Machine Learning · Statistics 2016-07-05 Soeren H. Welling , Hanne H. F. Refsgaard , Per B. Brockhoff , Line H. Clemmensen

The fast classification of new variable stars is an important step in making them available for further research. Selection of science targets from large databases is much more efficient if they have been classified first. Defining the…

Astrophysics · Physics 2009-11-13 J. Debosscher , L. M. Sarro , C. Aerts , J. Cuypers , B. Vandenbussche , R. Garrido , E. Solano

We describe an automatic procedure for determining abundances from high resolution spectra. Such procedures are becoming increasingly important as large amounts of data are delivered from 8m telescopes and their high-multiplexing fiber…

Astrophysics · Physics 2009-11-07 Piercarlo Bonifacio , Elisabetta Caffau

Automated techniques have been developed to automate the process of classification of objects or their analysis. The large datasets provided by upcoming spectroscopic surveys with dedicated telescopes urges scientists to use these automated…

Astrophysics · Physics 2009-06-23 Mahdi Bazarghan , Ranjan Gupta

Weak lensing is a potentially robust and model-independent cosmological probe, but its accuracy is dependent on knowledge of the redshift distribution of the source galaxies used. The most robust way to determine the redshift distribution…

Astrophysics · Physics 2009-11-10 Mustapha Ishak , Christopher M. Hirata

Traditional spectral analysis methods are increasingly challenged by the exploding volumes of data produced by contemporary astronomical surveys. In response, we develop deep-Regularized Ensemble-based Multi-task Learning with Asymmetric…

Solar and Stellar Astrophysics · Physics 2023-11-23 Sankalp Gilda

The Chinese Space Station Telescope (CSST) spectroscopic survey aims to deliver high-quality low-resolution ($R > 200$) slitless spectra for hundreds of millions of targets down to a limiting magnitude of about 21 mag, distributed within a…

Instrumentation and Methods for Astrophysics · Physics 2021-05-05 Haibo Yuan , Dingshan Deng , Yang Sun

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

The cosmological exploitation of modern photometric galaxy surveys requires both accurate (unbiased) and precise (narrow) redshift probability distributions derived from broadband photometry. Existing methodologies do not meet those…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-21 Boris Leistedt , David W. Hogg , Risa H. Wechsler , Joe DeRose

Stellar age determination for large samples of stars opens new avenues for a broad range of astronomical sciences. While precise stellar ages for evolved stars have been derived from large ground- and space-based stellar surveys, reliable…

Solar and Stellar Astrophysics · Physics 2025-08-06 Jia-Hui Wang , Maosheng Xiang , Meng Zhang , Jiwei Xie , Jian Ge , Jinghua Zhang , Lanya Mou , Jifeng Liu

Derived from first physical principles, a few simple rules are presented that can help in both the planning and interpretation of CCD and IR-array camera observations of resolvable stellar populations. These rules concern the overall size…

Astrophysics · Physics 2010-10-28 Alvio Renzini

The use of machine learning is becoming ubiquitous in astronomy, but remains rare in the study of the atmospheres of exoplanets. Given the spectrum of an exoplanetary atmosphere, a multi-parameter space is swept through in real time to find…

Earth and Planetary Astrophysics · Physics 2018-06-12 Pablo Marquez-Neila , Chloe Fisher , Raphael Sznitman , Kevin Heng

We calibrate spectrophotometric optical spectra of 32 stars commonly used as standard stars, referenced to 14 stars already on the HST-based CALSPEC flux system. Observations of CALSPEC and non-CALSPEC stars were obtained with the SuperNova…

Single-exposure spectra in large spectral surveys are valuable for time domain studies such as stellar variability, but there is no available method to eliminate cosmic rays for single-exposure, multi-fiber spectral images. In this paper,…

Instrumentation and Methods for Astrophysics · Physics 2017-05-08 Zhongrui Bai , Haotong Zhang , Hailong Yuan , Jeffrey L. Carlin , Guangwei Li , Yongheng Zhao , Zihuang Cao

One of important aims of astronomical data mining is to systematically search for specific rare objects in a massive spectral dataset, given a small fraction of identified samples with the same type. Most existing methods are mainly based…

Astrophysics of Galaxies · Physics 2016-03-23 Changde Du , Ali Luo , Haifeng Yang , Wen Hou , Yanxin Guo

This article investigates the problem of estimating stellar atmospheric parameters from spectra. Feature extraction is a key procedure in estimating stellar parameters automatically. We propose a scheme for spectral feature extraction and…

Instrumentation and Methods for Astrophysics · Physics 2015-08-04 Tan Yang , Xiangru Li

A number of spectroscopic surveys have been carried out or are planned to study the origin of the Milky Way. Their exploitation requires reliable automated methods and softwares to measure the fundamental parameters of the stars. Adopting…

Astronomical observations typically provide three-dimensional maps, encoding the distribution of the observed flux in (1) the two angles of the celestial sphere and (2) energy/frequency. An important task regarding such maps is to…

Instrumentation and Methods for Astrophysics · Physics 2024-01-09 Florian Wolf , Florian List , Nicholas L. Rodd , Oliver Hahn