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A large number of unidentified sources found by astronomical surveys and other observations necessitate the use of an automated classification technique based on machine learning methods. The aim of this paper is to find a suitable…

High Energy Astrophysical Phenomena · Physics 2023-02-20 Shivam Kumaran , Samir Mandal , Sudip Bhattacharyya , Deepak Mishra

We provide line luminosities and spectroscopic templates of prominent optical emission lines of 133 Galactic Wolf-Rayet stars by exploiting Gaia DR3 parallaxes and optical spectrophotometry, and provide comparisons with 112 counterparts in…

Solar and Stellar Astrophysics · Physics 2023-02-15 Paul A. Crowther , G. Rate , Joachim M. Bestenlehner

Photometric redshift estimation is a key requirement for modern large-area surveys, where spectroscopic measurements are observationally prohibitive. Seyfert II galaxies provide a particularly challenging test case due to the combined…

Astrophysics of Galaxies · Physics 2026-04-23 Uzay Aydin

Massive stars produce strong stellar winds that consist of continuous outflows of material at speeds of thousands of km/s. These winds convey large amounts of kinetic power, especially in the case of Wolf-Rayet (WR) stars. When these winds…

Solar and Stellar Astrophysics · Physics 2024-08-15 A. B. Blanco , M. De Becker , A. Saha , A. Tej , P. Benaglia

Wolf-Rayet (WR) stars, as they are advanced stages of the life of massive stars, provide a good test for various physical processes involved in the modelling of massive stars, such as rotation and mass loss. In this paper, we show the…

Solar and Stellar Astrophysics · Physics 2015-08-20 Cyril Georgy , Sylvia Ekström , Raphael Hirschi , Georges Meynet , José Groh , Patrick Eggenberger

We present a self-consistent study of the stellar populations and the ionized gas in a sample of 10 HII galaxies with, at least, four measured electron temperatures and a precise determination of ionic abundances following the "direct…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Enrique Perez-Montero , Ruben Garcia-Benito , Guillermo F. Hagele , Angeles I. Diaz

We introduce a new method to determine galaxy cluster membership based solely on photometric properties. We adopt a machine learning approach to recover a cluster membership probability from galaxy photometric parameters and finally derive…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-26 P. A. A. Lopes , A. L. B. Ribeiro

As part of a search for Wolf-Rayet (WR) stars in the Magellanic Clouds, we have discovered a new type of WR star in the Large Magellanic Cloud (LMC). These stars have both strong emission lines, as well as He ii and Balmer absorption lines…

Solar and Stellar Astrophysics · Physics 2017-05-31 Kathryn F. Neugent , Philip Massey , D. John Hillier , Nidia I. Morrell

We present the results of a programme to search and identify the nature of unusual sources within the All-sky Wide-field Infrared Survey Explorer (WISE) that is based on a machine-learning algorithm for anomaly detection, namely one-class…

We present a machine learning (ML) based method for automated detection of Gamma-Ray Burst (GRB) candidate events in the range 60 keV - 250 keV from the AstroSat Cadmium Zinc Telluride Imager data. We use density-based spatial clustering to…

Instrumentation and Methods for Astrophysics · Physics 2021-05-18 Sheelu Abraham , Nikhil Mukund , Ajay Vibhute , Vidushi Sharma , Shabnam Iyyani , Dipankar Bhattacharya , A. R. Rao , Santosh Vadawale , Varun Bhalerao

Classifying catalog objects as stars, galaxies, or AGN is a crucial part of any statistical study of galaxies. We describe our pipeline for binary (star/galaxy) and multiclass (star/galaxy/Type I AGN/Type II AGN) classification developed…

Astrophysics of Galaxies · Physics 2021-04-14 Anneya Golob , Marcin Sawicki , Andy D. Goulding , Jean Coupon

The hottest stars ($>$10,000 K), and by extension typically the most massive ones, are those that will be prevalent in the ultraviolet (UV) portion of the electromagnetic spectrum, and we expect numerous B, O, and Wolf-Rayet stars to be…

Solar and Stellar Astrophysics · Physics 2015-07-07 Dale Mudd , K. Z. Stanek

Wolf-Rayet stars have been identified as objects in their final phase of massive star evolution. It has been suggested that Wolf-Rayet stars are the progenitors of long-duration gamma ray bursts in low metallicity environments. However,…

Solar and Stellar Astrophysics · Physics 2010-07-27 Jorick S. Vink et al.

We present a new catalog of 11,209 O-rich AGB stars and 7172 C-rich AGB stars in our Galaxy identifying more AGB stars in the bulge component and considering more visual carbon stars. For each object, we cross-identify the IRAS, AKARI, MSX,…

Solar and Stellar Astrophysics · Physics 2021-10-20 Kyung-Won Suh

We present the ROGER (Reconstructing Orbits of Galaxies in Extreme Regions) code, which uses three different machine learning techniques to classify galaxies in, and around, clusters, according to their projected phase-space position. We…

(Abridged) We have performed a comprehensive multiwavelength analysis of a sample of 20 starburst galaxies that show the presence of a substantial population of massive stars. The main aims are the study of the massive star formation and…

Astrophysics · Physics 2011-08-31 Angel R. Lopez-Sanchez , Cesar Esteban

The spin of Wolf-Rayet (WR) stars at low metallicity (Z) is most relevant for our understanding of gravitational wave sources such as GW 150914, as well as the incidence of long-duration gamma-ray bursts (GRBs). Two scenarios have been…

Solar and Stellar Astrophysics · Physics 2017-07-19 Jorick S. Vink , Tim J. Harries

Studies of high-redshift gamma-ray bursts (GRBs) provide important information about the early Universe such as the rates of stellar collapsars and mergers, the metallicity content, constraints on the re-ionization period, and probes of the…

High Energy Astrophysical Phenomena · Physics 2016-03-23 T. N. Ukwatta , P. R. Wozniak , N. Gehrels

Gamma-Ray Bursts (GRBs), due to their high luminosities are detected up to redshift 10, and thus have the potential to be vital cosmological probes of early processes in the universe. Fulfilling this potential requires a large sample of…

There exist a variety of star-galaxy classification techniques, each with their own strengths and weaknesses. In this paper, we present a novel meta-classification framework that combines and fully exploits different techniques to produce a…

Instrumentation and Methods for Astrophysics · Physics 2015-08-20 Edward J. Kim , Robert J. Brunner , Matias Carrasco Kind
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