J-PLUS: Searching for very metal-poor star candidates using the SPEEM pipeline

DOI: 
10.1051/0004-6361/202141717
Publication date: 
01/01/2022
Main author: 
Galarza C.A.
IAA authors: 
Jiménez Teja, Yolanda
Authors: 
Galarza, Carlos Andrés;Daflon, Simone;Placco, Vinicius M.;Prieto, Carlos Allende;Borges Fernandes, Marcelo;Yuan, Haibo;López-Sanjuan, Carlos;Lee, Young Sun;Solano, Enrique;Jiménez-Esteban, F.;Sobral, David;Alvarez Candal, Alvaro;Pereira, Claudio B.;Akras, Stavros;Martín, Eduardo;Jiménez Teja, Yolanda;Cenarro, Javier;Cristóbal-Hornillos, David;Hernández-Monteagudo, Carlos;Marín-Franch, Antonio;Moles, Mariano;Varela, Jesús;Ramió, Héctor Vázquez;Alcaniz, Jailson;Dupke, Renato;Ederoclite, Alessandro;Sodré, Laerte;Angulo, Raul E.
Journal: 
Astronomy and Astrophysics
Publication type: 
Article
Volume: 
657.0
Pages: 
A35
Number: 
A35
Abstract: 
Context. We explore the stellar content of the Javalambre Photometric Local Universe Survey (J-PLUS) Data Release 2 and show its potential for identifying low-metallicity stars using the Stellar Parameters Estimation based on Ensemble Methods (SPEEM) pipeline. Aims. SPEEM is a tool used to provide determinations of atmospheric parameters for stars and separate stellar sources from quasars based on the unique J-PLUS photometric system. The adoption of adequate selection criteria allows for the identification of metal-poor star candidates that are suitable for spectroscopic follow-up investigations. Methods. SPEEM consists of a series of machine-learning models that use a training sample observed by both J-PLUS and the SEGUE spectroscopic survey. The training sample has temperatures, Teff, between 4800 K and 9000 K, values of log g between 1.0 and 4.5, as well as -3.1 < [Fe/H] < +0.5. The performance of the pipeline was tested with a sample of stars observed by the LAMOST survey within the same parameter range. Results. The average differences between the parameters of a sample of stars observed with SEGUE and J-PLUS, obtained with the SEGUE Stellar Parameter Pipeline and SPEEM, respectively, are ΔTeff ∼ 41 K, Δlog g ∼ 0.11 dex, and Δ[Fe/H] ∼ 0.09 dex. We define a sample of 177 stars that have been identified as new candidates with [Fe/H] < -2.5, with 11 of them having been observed with the ISIS spectrograph at the William Herschel Telescope. The spectroscopic analysis confirms that 64% of stars have [Fe/H] < -2.5, including one new star with [Fe/H] < -3.0. Conclusions. Using SPEEM in combination with the J-PLUS filter system has demonstrated their potential in estimating the stellar atmospheric parameters (Teff, log g, and [Fe/H]). The spectroscopic validation of the candidates shows that SPEEM yields a success rate of 64% on the identification of very metal-poor star candidates with [Fe/H] < -2.5.
Database: 
SCOPUS
ADS
URL: 
https://ui.adsabs.harvard.edu/#abs/2022A&A...657A..35G/abstract
ADS Bibcode: 
2022A&A...657A..35G
Keywords: 
Methods: data analysis | Stars: fundamental parameters | Stars: general | Stars: Population III | Stars: statistics